Metformin should be considered in the treatment of gestational diabetes: a prospective randomised study

A meta-analysis of metformin and insulin on maternal outcome and neonatal outcome in patients with gestational diabetes mellitus

INTRODUCTION

The use of metformin for treating gestational diabetes mellitus (GDM) remains controversial because it can pass through the placenta. This meta-analysis aimed to compare the effects of metformin and insulin on maternal and neonatal outcomes in patients with GDM.

METHODS

We conducted a comprehensive search of the PubMed, Embase, and Cochrane Library databases, focusing on randomized controlled trials (RCTs) that evaluated the impacts of metformin and insulin on both maternal and neonatal outcomes in patients with GDM.

RESULTS

Twenty-four RCTs involving 4934 patients with GDM were included in this meta-analysis. Compared with insulin, metformin demonstrated a significant reduction in the risks of preeclampsia (RR 0.61, 95% CI 0.48 to 0.78, p < .0001), induction of labor (RR 0.90, 95% CI 0.82 to 0.98, p = .02), cesarean delivery (RR 0.91, 95% CI 0.85 to 0.98, p = .01), macrosomia (RR 0.67, 95% CI 0.53 to 0.83, p = .0004), neonatal intensive care unit (NICU) admission (RR 0.75, 95% CI 0.66 to 0.86, p < .0001), neonatal hypoglycemia (RR 0.55, 95% CI 0.48 to 0.63, p < .00001), and large for gestational age (LGA) (RR 0.80, 95% CI 0.68 to 0.94, p = .007). Conversely, metformin showed no significant impact on gestational hypertension (RR 0.84, 95% CI 0.67 to 1.06, p = .15), spontaneous vaginal delivery (RR 1.13, 95% CI 1.00 to 1.08, p = .05), emergency cesarean section (RR 0.94, 95% CI 0.77 to 1.16, p = .58), shoulder dystocia (RR 0.65, 95% CI 0.31 to 1.39, p = .27), premature birth (RR 0. 92, 95% CI 0.61 to 1.39, p = .69), polyhydramnios (RR 1.11, 95% CI 0.54 to 2.30, p = .77), birth trauma (RR 0.87, 95% CI 0.54 to 1.39, p = .56), 5-min Apgar score < 7 (RR 1.13, 95% CI 0.76 to 1.68, p = .55), small for gestational age (SGA) (RR 0.93, 95% CI 0.71 to 1.22, p = .62), respiratory distress syndrome (RDS) (RR 0.74, 95% CI 0.50 to 1.08, p = .11), jaundice (RR 1.09, 95% CI 0.95 to 1.25, p = .24) or birth defects (RR 0.80, 95% CI 0.37 to 1.74, p = .57).

CONCLUSIONS

The findings suggest that metformin can reduce the risk of certain maternal and neonatal outcomes compared with insulin therapy for GDM. However, long-term follow-up studies of patients with GDM taking metformin and their offspring are warranted to provide further evidence.

Long term impact on offspring (5-11 years of age) of metformin use in pregnancy in mothers with diabetes: A systematic review and meta-analysis

BACKGROUND

Data is scant on impact of metformin use in gestational diabetes (GDM)/ diabetes in pregnancy (DIP) on long-term outcomes in children and mothers beyond 5-years of child-birth. This systematic-review and meta-analysis aimed to evaluate the long-term impact of metformin use in pregnancy on children and their mothers.

METHODS

Electronic databases were searched for studies evaluating metformin as compared to insulin for managing GDM/DIP. Primary outcome was to evaluate changes in body-mass index (BMI) in children at 5-11 years age. Secondary outcomes were to assess alterations in other anthropometric measures, obesity, changes in lipids and adipo-cytokines in children and mothers.

RESULTS

Children at 9-years age, born to mothers who were treated with metformin during pregnancy had similar BMI [MD1.09kg/m2(95%CI:-0.44-2.62);P=0.16;I2=16%], waist-circumference to height-ratio [MD0.13(95%CI:-0.05-0.30);P=0.16;I2=94%], dual-energy X-ray absorptiometry (DXA) total fat-mass [MD0.68kg(95%CI:-2.39-3.79);P=0.66;I2=70%], DXA-total fat-percent [MD 0.04%(95%CI:-3.44-3.51);P=0.98;I2=56%], DXA-total fat-free mass [MD 0.81kg (95%CI:-0.96-2.58);P=0.37;I2=55%], MRI visceral adipose tissue [MD 80.97cm3(95%CI:-136.47-298.41); P=0.47;I2=78%] and magnetic-resonance spectroscopy liver-fat percentage [MD 0.27%(95% CI:-1.26-1.79);P=0.73;I2=0%], compared to those born to mothers who were treated with insulin. Serum adiponectin, leptin, alanine-aminotransferase and ferritin were comparable among groups. In children between 9-11 years age, occurrence of obesity, diabetes or challenges in motor and social development were comparable between the 2 groups. After 9 years of childbirth, BMI and risk of developing diabetes were similar in the two groups of women.

CONCLUSION

Metformin use in pregnancy did not show any adverse effects when compared to insulin on long-term outcomes in children and their mothers.

Insulin Use During Gestational and Pre-existing Diabetes in Pregnancy: A Systematic Review of Study Design

INTRODUCTION

Insulin is the first-line pharmacologic therapy for women with diabetes in pregnancy. However, conducting well-designed randomized clinical trials (RCTs) and achieving recommended glycemic targets remains a challenge for this unique population. This systematic literature review (SLR) aimed to understand the evidence for insulin use in pregnancy and the outcome metrics most often used to characterize its effect on glycemic, maternal and fetal outcomes in gestational diabetes mellitus (GDM) and in pregnant women with diabetes.

METHODS

An SLR was conducted using electronic databases in Medline, EMBASE via Ovid platform, evidence-based medicine reviews (2010-2020) and conference proceedings (2018-2019). Studies were included if they assessed the effect of insulin treatment on glycemic, maternal or fetal outcomes in women with diabetes in pregnancy. Studies on any type of diabetes other than gestational or pre-existing diabetes as well as non-human studies were excluded.

RESULTS

In women diagnosed with GDM or pre-existing diabetes, most studies compared treatment of insulin with metformin (n = 35) followed by diet along with lifestyle intervention (n = 24) and glibenclamide (n = 12). Most studies reporting on glycemic outcomes compared insulin with metformin (n = 22) and glibenclamide (n = 4). Fasting blood glucose was the most reported clinical outcome of interest. Among the studies reporting maternal outcomes, method of delivery and delivery complications were most commonly reported. Large for gestational age, stillbirth and perinatal mortality were the most common fetal outcomes reported.

CONCLUSION

This SLR included a total of 108 clinical trials and observational studies with diverse populations and treatment arms. Outcomes varied across the studies, and a lack of consistent outcome measures to manage diabetes in pregnant women was observed. This elucidates a need for global consensus on study design and standardized clinical, maternal and fetal outcomes metrics.

Relationships Between Exposure to Gestational Diabetes Treatment and Neonatal Anthropometry: Evidence from the Born in Bradford (BiB) Cohort

OBJECTIVES

To examine the relationships between gestational diabetes mellitus (GDM) treatment and neonatal anthropometry.

METHODS

Covariate-adjusted multivariable linear regression analyses were used in 9907 offspring of the Born in Bradford cohort. GDM treatment type (lifestyle changes advice only, lifestyle changes and insulin or lifestyle changes and metformin) was the exposure, offspring born to mothers without GDM the control, and birth weight, head, mid-arm and abdominal circumference, and subscapular and triceps skinfold thickness the outcomes.

RESULTS

Lower birth weight in offspring exposed to insulin (- 117.2 g (95% CI - 173.8, - 60.7)) and metformin (- 200.3 g (- 328.5, - 72.1)) compared to offspring not exposed to GDM was partly attributed to lower gestational age at birth and greater proportion of Pakistani mothers in the treatment groups. Higher subscapular skinfolds in offspring exposed to treatment compared to those not exposed to GDM was partly attributed to higher maternal glucose concentrations at diagnosis. In fully adjusted analyses, offspring exposed to GDM treatment had lower weight, smaller abdominal circumference and skinfolds at birth than those not exposed to GDM. Metformin exposure was associated with smaller offspring mid-arm circumference (- 0.3 cm (- 0.6, - 0.07)) than insulin exposure in fully adjusted models with no other differences found.

CONCLUSIONS FOR PRACTICE

Offspring exposed to GDM treatment were lighter and smaller at birth than those not exposed to GDM. Metformin-exposed offspring had largely comparable birth anthropometric characteristics to those exposed to insulin.

Metformin Versus Insulin for Gestational Diabetes: Cognitive and Neuropsychological Profiles of Children Aged 9 years

OBJECTIVE

We compared cognitive profile and neuropsychological performance in 9-year-old offspring of mothers who were treated with metformin or insulin for gestational diabetes mellitus (GDM).

METHODS

A total of 172 children whose mothers were randomly assigned to receive either metformin or insulin for GDM were studied at the age of 9 years. Of these children, 127 were from Turku, Finland (63 metformin and 64 insulin), and 45 from Oulu, Finland (19 metformin and 26 insulin). Clinical and demographic background characteristics were obtained at enrolment, birth, and 9-year follow-up. Cognitive profiles were examined at age 9 years with the Wechsler Intelligence Scale for Children. Neuropsychological functions were examined with 2 subtests of the Developmental Neuropsychological Assessment test battery assessing comprehension of instructions and narrative memory, Trail Making Test assessing attention and with Behavioral Rating Inventory of Executive Functioning, including parent-rated and teacher-rated evaluations. Academic functioning was studied with reading fluency subtest of the Screening test for reading, writing, and calculus for first to sixth grades and information about educational support received at school reported by parents.

RESULTS

The cognitive profiles, including indexes of verbal comprehension, perceptual reasoning, working memory, and processing speed, did not differ significantly between metformin-treated and insulin-treated groups. Significant differences were not found between the treatment groups in assessed neuropsychological functions, reading fluency, or received level of support at school.

CONCLUSION

Cognitive and neuropsychological outcomes were similar in 9-year-old children whose mothers had either metformin or insulin treatment of GDM.

Focus on Metformin: Its Role and Safety in Pregnancy and Beyond

Metformin is used worldwide in the treatment of type 2 diabetes and has been used in the treatment of diabetes in pregnancy since the 1970s. It is highly acceptable to patients due to its ease of administration, cost and adverse effect profile. It is effective in reducing macrosomia, large-for-gestational-age infants and reduces maternal weight gain. Despite its many advantages, metformin has been associated with reductions in foetal size and has been associated with an increase in infants born small-for-gestational-age in certain cohorts. In this article, we review its efficacy, adverse effects and long-term follow-up before, during and after pregnancy for both mother and infant. We also evaluate the other forms of treatment for gestational diabetes, including oral therapies, insulin therapy and emerging treatments.

Lights and shadows on the use of metformin in pregnancy: from the preconception phase to breastfeeding and beyond

During pregnancy, the complex hormonal changes lead to a progressive decrease of insulin sensitivity that can drive the onset of gestational diabetes (GDM) or worsen an already-known condition of insulin resistance like type 2 diabetes, polycystic ovarian syndrome (PCOS), and obesity, with complications for the mother and the fetus. Metformin during pregnancy is proving to be safe in a growing number of studies, although it freely crosses the placenta, leading to a fetal level similar to maternal concentration. The aim of this literature review is to analyze the main available evidence on the use of metformin during, throughout, and beyond pregnancy, including fertilization, lactation, and medium-term effects on offspring. Analyzed studies support the safety and efficacy of metformin during pregnancy. In pregnant women with GDM and type 2 diabetes, metformin improves obstetric and perinatal outcomes. There is no evidence that it prevents GDM in women with pregestational insulin resistance or improves lipid profile and risk of GDM in pregnant women with PCOS or obesity. Metformin could have a role in reducing the risk of preeclampsia in pregnant women with severe obesity, the risk of late miscarriages and preterm delivery in women with PCOS, and the risk of ovarian hyperstimulation syndrome, increasing the clinical pregnancy rate in women with PCOS undergoing in vitro fertilization (IVF/FIVET). Offspring of mothers with GDM exposed to metformin have no significant differences in body composition compared with insulin treatment, while it appears to be protective for metabolic and cardiovascular risk.

Metformin restrains ZIKV replication and alleviates virus-induced inflammatory responses in microglia

The re-emergence of Zika virus (ZIKV) remains a major public health threat that has raised worldwide attention. Accumulating evidence suggests that ZIKV can cause serious pathological changes to the human nervous system, including microcephaly in newborns. Recent studies suggest that metformin, an established treatment for diabetes may play a role in viral infection; however, little is known about the interactions between ZIKV infection and metformin administration. Using fluorescent ZIKV by flow cytometry and immunofluorescence imaging, we found that ZIKV can infect microglia in a dose-dependent manner. Metformin diminished ZIKV replication without the alteration of viral entry and phagocytosis. Our study demonstrated that metformin downregulated ZIKV-induced inflammatory response in microglia in a time- and dose-dependent manner. Our RNA-Seq and qRT-PCR analysis found that type I and III interferons (IFN), such as IFNα2, IFNβ1 and IFNλ3 were upregulated in ZIKV-infected cells by metformin treatment, accompanied with the downregulation of GBP4, OAS1, MX1 and ISG15. Together, our results suggest that metformin-mediated modulation in multiple pathways may attribute to restraining ZIKV infection in microglia, which may provide a potential tool to consider for use in unique clinical circumstances.

Metformin versus insulin for gestational diabetes: Adiposity variables and adipocytokines in offspring at age of 9 years

AIMS

To compare body composition, visceral adiposity, adipocytokines, and low-grade inflammation markers in prepubertal offspring of mothers who were treated with metformin or insulin for gestational diabetes mellitus (GDM).

METHODS

172 offspring of 311 mothers randomized to receive metformin (n=82) or insulin (n=90) for GDMwere studied at 9 years of age (follow-up rate 55%). Measurements included anthropometrics, adipocytokines, markers of the low-grade inflammation, abdominal magnetic resonance imaging (MRI), magnetic liver spectrometry (MRS), and whole body dual-energy X-ray absorptiometry (DXA).

RESULTS

Serum markers of low-grade inflammation, visceral adipose tissue volume, total fat percentage, and liver fat percentage were similar between the study groups. Serum adiponectin concentration was higher in children in the metformin group compared to insulin group (median 10.37 vs 9.50 µg/ml, p = 0.016). This difference between groups was observed in boys only (median 12.13 vs 7.50 µg/ml, p<0.001). Leptin/adiponectin-ratio was lower in boys in the metformin group than in the insulin group (median 0.30 vs 0.75; p = 0.016).

CONCLUSIONS

Maternal metformin treatment for GDM had no effects on adiposity, body composition, liver fat, or inflammation markers in prepubertal offspring compared to maternal insulin treatment but was associated with higher adiponectin concentration and lower leptin/adiponectin-ratio in boys.

Short-term neonatal outcomes in women with gestational diabetes treated using metformin versus insulin: a systematic review and meta-analysis of randomized controlled trials

AIMS

To expand the evidence base for the clinical use of metformin, we conducted a meta-analysis of randomized controlled trials (RCTs) comparing the efficacy and safety of metformin versus insulin with respect to short-term neonatal outcomes.

METHODS

A comprehensive search of electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) was performed. Two reviewers extracted the data and calculated pooled estimates by use of a random-effects model. In total, 24 studies involving 4355 participants met the eligibility criteria and were included in the quantitative analyses.

RESULTS

Unlike insulin, metformin lowered neonatal birth weights (mean difference - 122.76 g; 95% confidence interval [CI] - 178.31, - 67.21; p < 0.0001), the risk of macrosomia (risk ratio [RR] 0.68; 95% CI 0.54, 0.86; p = 0.001), the incidence of neonatal intensive care unit admission (RR 0.73; 95% CI 0.61, 0.88; p = 0.0009), and the incidence of neonatal hypoglycemia (RR 0.65; 95% CI 0.52, 0.81; p = 0.0001). Subgroup analysis based on the maximum daily oral dose of metformin indicated that metformin-induced neonatal birth weight loss was independent of the oral dose.

CONCLUSIONS

Our meta-analysis provides further evidence that metformin is a safe oral antihyperglycemic drug and has some benefits over insulin when used for the treatment of gestational diabetes, without an increased risk of short-term neonatal adverse outcomes. Metformin may be particularly useful in women with gestational diabetes at high risk for neonatal hypoglycemia, women who want to limit maternal and fetal weight gain, and women with an inability to afford or use insulin safely.

Systematic review of the use of metformin compared to insulin for the management of gestational diabetes: Implications for low-resource settings

Introduction

This systematic review examines the effectiveness of metformin treatment compared to insulin treatment for gestational diabetes within the context of a low-resource environment.

Methods

Electronic data searches of Medline, EMBASE, Scopus and Google scholar databases from 1 January, 2005 to 30 June, 2021 were performed using medical subject headings: 'gestational diabetes or pregnancy diabetes mellitus' AND 'Pregnancy or pregnancy outcomes' AND 'Insulin' AND 'Metformin Hydrochloride Drug Combination/or Metformin/or Hypoglycemic Agents' AND 'Glycemic control or blood glucose'. Randomized controlled trials were included if: participants were pregnant women with gestational diabetes mellitus (GDM); the interventions were metformin and/or insulin. Studies among women with pre-gestational diabetes, non-randomised control trials or studies with a limited description of the methodology were excluded. Outcomes included adverse maternal outcomes: weight gain, C-section, pre-eclampsia and glycaemic control and adverse neonatal outcomes: birth weight, macrosomia, pre-term birth and neonatal hypoglycaemia. The revised Cochrane Risk of Bias Assessment for randomised trials was used for the evaluation of bias.

Results

We screened 164 abstracts and 36 full-text articles. Fourteen studies met the inclusion criteria. The studies provide moderate to high-quality evidence demonstrating the effectiveness of metformin as an alternative therapy to insulin. Risk of bias was low; multiple countries and robust sample sizes improved external validity. All studies were from urban centres with no rural data.

Conclusion

These recent high quality studies comparing metformin to insulin for the treatment of GDM generally found either improved or equivalent pregnancy outcome and good glycaemic control for most patients, although many required insulin supplementation. Its ease of use, safety and efficacy suggest metformin may simplify the management of gestational diabetes, particularly in rural and other low-resource environments.

[Gestational diabetes mellitus (Update 2023)]

Gestational diabetes (GDM) is defined as any degree of glucose intolerance with onset during pregnancy and is associated with increased feto-maternal morbidity as well as long-term complications in mothers and the offspring. Women detected to have diabetes early in pregnancy receive the diagnosis of overt, non-gestational, diabetes (glucose: fasting ≥ 126 mg/dl, spontaneous ≥ 200 mg/dl or HbA_1c ≥ 6.5% before 20 weeks of gestation). GDM is diagnosed by an oral glucose tolerance test (oGTT) or increased fasting glucose (≥ 92 mg/dl). Screening for undiagnosed type 2 diabetes at the first prenatal visit is recommended in women at increased risk (history of GDM/pre-diabetes; malformation, stillbirth, successive abortions or birth weight > 4500 g previously; obesity, metabolic syndrome, age > 35 years, vascular disease; clinical symptoms of diabetes (e.g. glucosuria) or ethnic origin with increased risk for GDM/T2DM (Arab, South- and Southeast Asian, Latin American)) using standard diagnostic criteria. Performance of the oGTT (120 min; 75 g glucose) may already be indicated in the first trimester in high-risk women but is mandatory between gestational week 24-28 in all pregnant women with previous non-pathological glucose metabolism. Following WHO recommendations, which are based on the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, GDM is defined, if fasting venous plasma glucose is ≥ 92 mg/dl or 1 h ≥ 180 mg/dl or 2 h ≥ 153 mg/dl after glucose loading (international consensus criteria). In case of one pathological value a strict metabolic control is mandatory. After bariatric surgery we do not recommend to perform an oGTT due to risk of postprandial hypoglycemia. All women with GDM should receive nutritional counseling, be instructed in blood glucose self-monitoring and motivated to increase physical activity to moderate intensity levels-if not contraindicated (Evidence level A). If blood glucose levels cannot be maintained in the therapeutic range (fasting < 95 mg/dl and 1 h after meals < 140 mg/dl, Evidence level B) insulin therapy should be initiated as first choice (Evidence level A). Maternal and fetal monitoring is required in order to minimize maternal and fetal/neonatal morbidity and perinatal mortality. Regular obstetric examinations including ultrasound examinations are recommended (Evidence level A). Neonatal care of GDM offspring at high risk for hypoglycaemia includes blood glucose measurements after birth and if necessary appropriate intervention. Monitoring the development of the children and recommendation of healthy lifestyle are important issues to be tackled for the whole family. After delivery all women with GDM have to be reevaluated as to their glucose tolerance by a 75 g oGTT (WHO criteria) 4-12 weeks postpartum. Assessment of glucose parameters (fasting glucose, random glucose, HbA_1c or optimally oGTT) are recommended every 2-3 years in case of normal glucose tolerance. All women have to be instructed about their increased risk of type 2 diabetes and cardiovascular disease at follow-up. Possible preventive meassures, in particular lifestyle changes as weight management and maintenance/increase of physical activity should be discussed (evidence level A).

Impact of pharmacological treatment of gestational diabetes on the mode of delivery and birth weight: a nationwide population-based study on a subset of singleton pregnant Portuguese women

AIMS

To access the impact of increasing use of metformin on cesarean section and large for gestational age rates, when compared to insulin.

METHODS

A retrospective observational study was developed using data from the Portuguese National Registry, between 2011 and 2019, of 5038 Portuguese women with single pregnancies and gestational diabetes treated with metformin and/or insulin. Three groups were defined according to the therapeutic regimen adopted: g1-insulin in monotherapy (n = 3027[60.1%]); g2-metformin in monotherapy (n = 1366[27.1%]); g3-metformin and insulin (n = 645[12.8%]). Multivariate analysis was adjusted for statistically significant covariates.

RESULTS

The cesarean section rate in g1 was similar to g2 (g1:36.9% vs. g2:37%, p = 0.982), although g3 was associated with cesarean delivery (g3:43.6% vs. g1:36.9%, p = 0.005; g3:43.6% vs. g1:37.0%, p = 0.002), with no differences reported in the multivariate analysis adjusted for year of delivery and pregestational body mass index. A delivery of a large for gestational age newborn was less frequently observed in g2 than in g1 (g2:4.1% vs. g1:5.4%, p = 0.044) and in g3 (g2:4.1% vs. g3:9.1%, p < 0.001), and in g1, when compared to g3 (g1:5.4% vs. g3:9.1%, p < 0.001). In the multivariate analysis, g2 showed lower odds of delivering a large for gestational age newborn, compared to g1 (β = -0.511, OR = 0.596, CI95% = 0.428-0.832, p < 0.001).

CONCLUSIONS

The use of metformin was not associated with higher cesarean section rates, compared to insulin. Instead, it was suggested a protective role of metformin on large gestational age rates. The concomitant use of dual therapy suggests more complex pregnancies, requiring closer surveillance that mitigate serious perinatal and obstetrical outcomes.

Maternal Treatment with Metformin Persistently Ameliorates High-Fat Diet-Induced Metabolic Symptoms and Modulates Gut Microbiota in Rat Offspring

A maternal high-fat (HF) diet has long-term deleterious effect on offspring. This study aims to evaluate whether maternal metformin (MT) treatment ameliorates the adverse effects of maternal HF diet on offspring and the role of gut microbiota in it. Pregnant Sprague-Dawley rats were randomly assigned to a HF diet (60% fat) or a standard chow diet (11.8% fat) group, and part of the HF diet group rats were co-treated with MT via drinking water (300 mg/kg/day), resulting in three groups according to maternal diet and MT treatment during gestation and lactation. All offspring were weaned on a chow diet. A maternal HF diet showed a significant deleterious effect on offspring’s metabolic phenotype and induced colonic inflammation and gut-barrier disruption through the reshaped gut microbiota. The daily oral administration of MT to HF-fed dams during gestation and lactation reversed the dysbiosis of gut microbiota in both dams and adult offspring. The hypothalamic TGR5 expression and plasma bile acids composition in adult male offspring was restored by maternal MT treatment, which could regulate hypothalamic appetite-related peptides expression and alleviate inflammation, thereby improving male offspring’s metabolic phenotype. The present study indicates that targeting the gut–brain axis through the mother may be an effective strategy to control the metabolic phenotype of offspring.

Comparison of glucose metabolism and anthropometry in women with previous gestational diabetes treated with metformin vs. insulin: 9-year follow-up of two randomized trials

INTRODUCTION

The main aim was to study whether the long-term incidences of type 2 diabetes, pre-diabetes and metabolic syndrome differed between women who were treated with metformin or insulin for gestational diabetes.

MATERIAL AND METHODS

This 9-year follow-up study of two open-label randomized trials compares metformin and insulin treatments of gestational diabetes. In all, 165 women, 88 previously treated with insulin and 77 treated with metformin in the index pregnancy, were included in the analyses. An oral glucose tolerance test was performed, and measures of anthropometry, glucose metabolism, serum lipids and inflammatory markers were compared between the treatment groups. Disorders of glucose metabolism (pre-diabetes and type 2 diabetes) at the 9-year follow-up was the primary outcome of this study. This study was registered at ClinicalTrials.gov: NCT02417090.

RESULTS

The incidences of pre-diabetes and type 2 diabetes (40.3% vs. 46.6%, odds ratio [OR] 0.77, 95% CI 0.40-1.50, p = 0.51), type 2 diabetes (14.3% vs. 15.9%, OR 0.88, 95% CI 0.34-2.26, p = 0.94), pre-diabetes (26.0% vs. 30.7%, OR 0.79, 95% CI 0.38-1.65, p = 0.62), and metabolic syndrome (45.9% vs. 55.2%, OR 0.69, 95% CI 0.35-1.35, p = 0.31) were comparable between the metformin and insulin groups. Moreover, there were no evident differences in the individual measures of anthropometry, glucose metabolism including HOMA-insulin resistance, serum lipids or inflammatory markers between the two treatment groups.

CONCLUSIONS

Treatment of gestational diabetes with metformin vs. insulin during pregnancy is unlikely to have diverging long-term effects on maternal anthropometry, glucose metabolism or serum lipids. From this perspective, both treatments may be considered in gestational diabetes.

Comparison of the effectiveness and safety of insulin and oral hypoglycemic drugs in the treatment of gestational diabetes mellitus: a meta-analysis of 26 randomized controlled trials

OBJECTIVE

Oral hypoglycemic drugs for the treatment of gestational diabetes mellitus (GDM) are still controversial because they can pass through the placenta. The purpose of this meta-analysis is to evaluate the safety and effectiveness of oral hypoglycemic drugs.

METHODS

PubMed, Ovid Embase, Web of Science, and Cochrane databases were systematically searched (inception to 20 April 2021). Rev Man 5.0 was used to analyze the data. A random-effects model was used to compute the summary risk estimates.

RESULTS

There were 26 randomized controlled trials (RCTs) involving 4921 GDM patients which were included in this meta-analysis. Compared with metformin, insulin had a significant increase in the risk of preeclampsia (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.06 to 2.45; I²=40%; p < .05), hypertension (OR, 1.42; 95% CI, 1.02 to 1.99; I²=0%; p < .05), hypoglycemia (OR, 3.93; 95% CI, 1.27 to 12.19; I²=0%; p < .05), neonatal hypoglycemia (OR, 1.92; 95% CI, 1.34 to 2.76; I²=41%; p < .0001), neonatal jaundice (OR, 2.70; 95% CI, 1.12 to 6.52; I²=0%; p < .05), and Neonatal Intensive Care Unit Admission (OR, 1.46; 95% CI, 1.09 to 1.95; I²=39%; p < .05), but the risk of neonatal macrosomia (OR, 1.67; 95% CI, 1.12 to 2.40; I²=0%; p < .05) and neonatal injury (OR, 0.70; 95% CI, 0.55 to 0.89; I²=0%; p < .01) is lower.

CONCLUSIONS

Metformin is comparable with insulin in glycemic control and neonatal outcomes and has the potential to replace insulin therapy in clinical practice. Glyburide is behind metformin and insulin, and more RCTs are needed to verify its safety.

Metformin: A promising option for the management of gestational diabetes mellitus - Exploring the benefits, challenges and clinical needs in the current management of gestational diabetes mellitus

The incidence of gestational diabetes mellitus (GDM) is increasing. One in three women require insulin to achieve glycaemic targets in GDM. However, it is unclear whether insulin therapy alone is the most effective treatment for all women in achieving glycaemic control and preventing adverse pregnancy outcomes. Although no oral hypoglycaemic agents are approved for pregnancy in Australia, recent research indicates that metformin is effective in preventing adverse perinatal outcomes and may even have possible benefits in the long term. Furthermore, there appears to be a specific role for both metformin and insulin among the GDM population. Metformin provides an option to offer an individualised approach to treat GDM.

Metformin versus insulin therapy for gestational diabetes: Effects on offspring anthropometrics and metabolism at the age of 9 years: A follow-up study of two open-label, randomized controlled trials

AIMS

To compare anthropometrics, and lipid and glucose metabolism in the 9-year-old offspring of mothers treated with metformin or insulin for gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

This was a Finnish two-centre, 9-year follow-up study of two open-label, randomized controlled trials comparing the effects observed in the offspring of mothers who received metformin and insulin treatment for GDM. Measurements included anthropometrics, blood pressure, lipoproteins, and oral glucose tolerance tests. This study was registered with ClinicalTrials.gov, number NCT02417090.

RESULTS

At the age of 9 years 172 children (55% of the original study cohort, 82 from the metformin and 90 from the insulin group) participated in the study. No differences were found between the 9-year-old offspring groups in anthropometric variables, including body mass index and waist-to-height ratio. The offspring in the metformin group had higher high-density lipoprotein (HDL) cholesterol concentrations (1.72 vs. 1.54 mmol/L; P = 0.039) but lower low-density lipoprotein cholesterol (2.39 vs. 2.58 mmol/L; P = 0.046) and apolipoprotein B concentrations (0.63 vs. 0.67 g/L; P = 0.043) than the offspring in the insulin group. The difference in HDL cholesterol concentration was found to be significant only in boys (P = 0.003). The 2-hour glucose value in the oral glucose tolerance test was 0.6-mmol/L lower in boys from the metformin group than in those from the insulin group (P = 0.015).

CONCLUSIONS

Metformin treatment for GDM is associated with similar offspring growth and glucose metabolism but a more favourable lipid profile at the age of 9 years as compared to insulin treatment.

Metformin for pregnancy and beyond: the pros and cons

CONTEXT AND AIM

Metformin has been used in pregnancy since the 1970s. It is cheap, widely available and is acceptable to women. Despite its increasing use, controversy remains surrounding its benefits and risks. Metformin effectively reduces hyperglycaemia for the mother during pregnancy and it reduces rates of macrosomia and neonatal hypoglycaemia. However, concern exists surrounding an increase in the rate of SGA births and obesity in childhood. We aim to review the evidence and expert opinion behind metformin in pregnancy through to the post-partum period.

METHODS

We performed a literature review of relevant studies from online databases using a combination of keywords. We also searched the references of retrieved articles for pertinent studies.

RESULTS

There is strong evidence that metformin is safe in early pregnancy with no risk of congenital malformations. If used throughout pregnancy, it is likely to lead to reduced maternal weight gain and reduced insulin dose in women with type 2 diabetes. In infants, metformin reduces hypoglycaemia and macrosomia but may increase the rate of infants born SGA. There is some evidence of an increased risk of obesity and altered fat distribution in offspring. Metformin appears well tolerated in pregnancy and is more acceptable to women than insulin therapy.

CONCLUSION

Due to increasing rates of maternal obesity, GDM and type 2 diabetes, metformin use in pregnancy is increasing. Overall, it appears safe and effective but further research is needed to examine mechanisms linking metformin to obesity reported during childhood in some follow-up studies.

Changing patterns in medication prescription for gestational diabetes during a time of guideline change in the USA: a cross-sectional study

OBJECTIVE

To define patterns of prescription and factors associated with choice of pharmacotherapy for gestational diabetes mellitus (GDM), namely metformin, glyburide and insulin, during a period of evolving professional guidelines.

DESING

Cross-sectional study.

SETTING

US commercial insurance beneficiaries from Market-Scan (late 2015 to 2018).

STUDY DESIGN

We included women with GDM, singleton gestations, 15-51 years of age on pharmacotherapy. The exposure was pharmacy claims for metformin, glyburide and insulin.

MAIN OUTCOMES

Pharmacotherapy for GDM with either oral agent, metformin or glyburide, compared with insulin as the reference, and secondarily, consequent treatment modification (addition and/or change) to metformin, glyburide or insulin.

RESULTS

Among 37 762 women with GDM, we analysed data from 10 407 (28%) with pharmacotherapy, 21% with metformin (n = 2147), 48% with glyburide (n = 4984) and 31% with insulin (n = 3276). From late 2015 to 2018, metformin use increased from 17 to 29%, as did insulin use from 26 to 44%, whereas glyburide use decreased from 58 to 27%. By 2018, insulin was the most common pharmacotherapy for GDM; metformin was more likely to be prescribed by 9% compared with late 2015/16, but glyburide was less likely by 45%. Treatment modification occurred in 20% of women prescribed metformin compared with 2% with insulin and 8% with glyburide.

CONCLUSIONS

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for GDM among a privately insured US population during a time of evolving professional guidelines. Further evaluation of the relative effectiveness and safety of metformin compared with insulin is needed.

TWEETABLE ABSTRACT

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for gestational diabetes mellitus in the USA.

Metformin in pregnancy and risk of adverse long-term outcomes: a register-based cohort study

This study aimed to investigate if maternal pregnancy exposure to metformin is associated with increased risk of long-term and short-term adverse outcomes in the child. RESEARCH DESIGN AND METHODS : This register-based cohort study from Finland included singleton children born 2004-2016 with maternal pregnancy exposure to metformin or insulin (excluding maternal type 1 diabetes): metformin only (n=3967), insulin only (n=5273) and combination treatment (metformin and insulin; n=889). The primary outcomes were long-term offspring obesity, hypoglycemia, hyperglycemia, diabetes, hypertension, polycystic ovary syndrome, and challenges in motor-social development. In a sensitivity analysis, the primary outcomes were investigated only among children with maternal gestational diabetes. Secondary outcomes were adverse outcomes at birth. Analyses were conducted using inverse- probability of treatment weighting (IPTW), with insulin as reference. RESULTS  : Exposure to metformin or combination treatment versus insulin was not associated with increased risk of long-term outcomes in the main or sensitivity analyses. Among the secondary outcomes, increased risk of small for gestational age (SGA) was observed for metformin (IPTW-weighted OR 1.65, 95% CI 1.16 to 2.34); increased risk of large for gestational age, preterm birth and hypoglycemia was observed for combination treatment. No increased risk was observed for neonatal mortality, hyperglycemia, or major congenital anomalies. CONCLUSIONS : This study found no increased long-term risk associated with pregnancy exposure to metformin (alone or in combination with insulin), compared with insulin. The increased risk of SGA associated with metformin versus insulin suggests caution in pregnancies with at-risk fetal undernutrition. The increased risks of adverse outcomes at birth associated with combination treatment may reflect confounding by indication or severity.

Associations between maternal characteristics and pharmaceutical treatment of gestational diabetes: an analysis of the UK Born in Bradford (BiB) cohort study

OBJECTIVES

To identify the maternal characteristics associated with pharmaceutical treatment of gestational diabetes mellitus (GDM).

DESIGN

Prospective birth cohort study.

SETTING

Bradford, UK.

PARTICIPANTS

762 women from the Born in Bradford (BiB) cohort who were treated for GDM in a singleton pregnancy. BiB cohort participants were recruited from 2007 to 2010. All women booked for delivery were screened for GDM between 26 and 28 weeks of gestation using a 75 g 2-hour oral glucose tolerance test (OGTT).

OUTCOME MEASURE

GDM treatment type: lifestyle changes advice (lifestyle changes), lifestyle changes advice with supplementary insulin (insulin) and lifestyle changes advice with supplementary metformin (metformin).

RESULTS

244 (32%) women were prescribed lifestyle changes advice alone while 518 (68%) were offered supplemental pharmaceutical treatment. The odds of receiving pharmaceutical treatment relative to lifestyle changes advice alone were increased for mothers who were obese (OR 4.6, 95% CI 2.8 to 7.5), those who smoked (OR 2.6, 95% CI 1.2 to 5.5) and had higher fasting glucose levels at OGTT (OR 2.1, 95% CI 1.6 to 2.7). The odds of being prescribed pharmaceutical treatment rather than lifestyle changes advice were lower for Pakistani women (OR 0.7, 95% CI 0.4 to 1.0)) than White British women. Relative to insulin treatment, metformin was more likely to be offered to obese women than normal weight women (relative risk ratio, RRR 3.2, 95% CI 1.3 to 7.8) and less likely to be prescribed to women with higher fasting glucose concentrations at OGTT (RRR 0.3, 95% CI 0.2 to 0.6).

CONCLUSIONS

In the BiB cohort, GDM pharmaceutical treatment tended to be prescribed to women who were obese, White British, who smoked and had more severe hyperglycaemia. The characteristics of metformin-treated mothers differed from those of insulin-treated mothers as they were more likely to be obese but had lower glucose concentrations at diagnosis.

Metformin for gestational diabetes study: metformin vs insulin in gestational diabetes: glycemic control and obstetrical and perinatal outcomes: randomized prospective trial

BACKGROUND

Gestational diabetes that is not properly controlled with diet has been commonly treated with insulin. In recent years, several studies have published that metformin can lead to, at least, similar obstetrical and perinatal outcomes as insulin. Nevertheless, not all clinical guidelines endorse its use, and clinical practice is heterogeneous.

OBJECTIVE

This study aimed to test whether metformin could achieve the same glycemic control as insulin and similar obstetrical and perinatal results, with a good safety profile, in women with gestational diabetes that is not properly controlled with lifestyle changes.

STUDY DESIGN

The metformin for gestational diabetes study was a multicenter, open-label, parallel arms, randomized clinical trial performed at 2 hospitals in Málaga (Spain), enrolling women with gestational diabetes who needed pharmacologic treatment. Women at the age of 18 to 45 years, in the second or third trimesters of pregnancy, were randomized to receive metformin or insulin (detemir or aspart). The main outcomes were (1) glycemic control (mean glycemia, preprandial and postprandial) and hypoglycemic episodes and (2) obstetrical and perinatal outcomes and complications (hypertensive disorders, type of labor, prematurity, macrosomia, large for gestational age, neonatal care unit admissions, respiratory distress syndrome, hypoglycemia, jaundice). Outcomes were analyzed on an intention-to-treat basis.

RESULTS

Between October 2016 and June 2019, 200 women were randomized, 100 to the insulin-treated group and 100 to the metformin-treated group. Mean fasting and postprandial glycemia did not differ between groups, but postprandial glycemia was significantly better after lunch or dinner in the metformin-treated-group. Hypoglycemic episodes were significantly more common in the insulin-treated group (55.9% vs 17.7% on metformin; odds ratio, 6.118; 95% confidence interval, 3.134-11.944; P=.000). Women treated with metformin gained less weight from the enrollment to the prepartum visit (36-37 gestational weeks) (1.35±3.21 vs 3.87±3.50 kg; P=.000). Labor inductions (45.7% [metformin] vs 62.5% [insulin]; odds ratio, 0.506; 95% confidence interval, 0.283-0.903; P=.029) and cesarean deliveries (27.6% [metformin] vs 52.6% [insulin]; odds ratio, 0.345; 95% confidence interval, 0.187-0.625; P=.001) were significantly lower in the metformin-treated group. Mean birthweight, macrosomia, and large for gestational age and babies' complications were not different between treatment groups. The lower cesarean delivery rate for women treated with metformin was not associated with macrosomia, large or small for gestational age, or other complications of pregnancy.

CONCLUSION

Metformin treatment was associated with a better postprandial glycemic control than insulin for some meals, a lower risk of hypoglycemic episodes, less maternal weight gain, and a low rate of failure as an isolated treatment. Most obstetrical and perinatal outcomes were similar between groups.

Glycemic control and neonatal outcomes in women with gestational diabetes mellitus treated using glyburide, metformin, or insulin: a pairwise and network meta-analysis

AIMS

We aimed to assess the comparative efficiency and safety of the use of glyburide, metformin, and insulin in gestational diabetes mellitus (GDM).

METHODS

We searched for randomized controlled trials that compared glyburide, metformin, and insulin in GDM. Data regarding glycemic control and neonatal safety were collected and analyzed in pairwise and network meta-analyses.

RESULTS

A total of 4533 individuals from 23 trials were included. Compared with glyburide, metformin reduced 2-h postprandial blood glucose (2HPG) to a greater extent (standard mean difference (SMD) 0.18; 95% credible interval (CI) 0.01, 0.34). There were significantly lower prevalence of neonatal hypoglycemia (risk difference (RD) - 0.07; 95%CI - 0.11, - 0.02) and preeclampsia (RD - 0.03; 95%CI - 0.06, 0) in the metformin group than in the insulin group. The metformin group had significantly lower birth weight (SMD - 0.17; 95%CI - 0.25, - 0.08) and maternal weight gain (SMD - 0.61; 95%CI - 0.86,- 0.35) compared with the insulin group. Network meta-analysis suggested that metformin had the highest probability of successfully controlling glycemia and preventing neonatal complications.

CONCLUSIONS

The present meta-analysis suggests that metformin may be as effective as insulin for glycemic control and is the most promising drug for the prevention of neonatal and maternal complications.

Effects of Different Glucose-Lowering Measures on Maternal and Infant Outcomes in Pregnant Women with Gestational Diabetes: A Network Meta-analysis

INTRODUCTION

A network meta-analysis was conducted to compare and rank the effects of different glucose-lowering measures on maternal and infant outcomes in pregnant women with gestational diabetes mellitus (GDM).

METHODS

We searched the PubMed, CNKI, Embase, Cochrane Library, Wanfang, and Weipu databases for relevant studies published between database establishment and June 2021. Study retrieval involved subject-heading and keyword searches. Randomized controlled trials (RCTs) with different glucose-lowering treatments for GDM patients were included. The Cochrane tool was used to assess bias risk. Pairwise and network meta-analyses were used to compare and rank the effects of different hypoglycemic measures on maternal and infant outcomes in pregnant women with GDM.

RESULTS

We included 41 RCTs involving 6245 pregnant women with GDM. Patients treated with insulin had a higher incidence of neonatal intensive care unit (NICU) occupancy (1.3, 95% CI 1.0-1.7) than those treated with metformin. The insulin (1.5, 95% CI 1.1-2.1 and 1.8, 95% CI 1.0-3.3) and glyburide (2.0, 95% CI 1.2-3.2 and 2.5, 95% CI 1.1-8.4) groups exhibited higher incidences of neonatal hypoglycemia and large for gestational age (LGA) newborns than the metformin group. The glyburide group exhibited a lower probability of cesarean section than the metformin (0.76, 95% CI 0.55-1.0) and insulin (0.71, 95% CI 0.52-0.96) groups. Preeclampsia incidence in the diet and exercise groups was significantly lower than in the metformin (0.19, 95% CI 0.043-0.72) and insulin (0.15, 95% CI 0.032-0.52) groups. No intervention significantly reduced the incidences of macrosomia, preterm birth, gestational hypertension, or respiratory distress syndrome (RDS). The ranking results showed that the metformin group had the lowest rates of neonatal hypoglycemia, macrosomia, LGA, and NICU occupancy. The glyburide group had the lowest NICU occupancy and cesarean section rates and the highest neonatal hypoglycemia, LGA, preeclampsia, and gestational hypertension rates. The diet and exercise group had the lowest preterm delivery and preeclampsia rates and the highest NICU occupancy rate.

CONCLUSION

Metformin is a potentially superior choice for GDM treatment because it is associated with minimal incidences of multiple adverse pregnancy outcome indicators and does not lead to high values of certain adverse outcome indices. Other hypoglycemic agent or diet groups exhibit high incidences of certain adverse outcomes. Therefore, when selecting a GDM treatment strategy, the efficacies and risks of different treatment programs should be evaluated according to the scenario in hand.

The efficacy and safety of metformin alone or as an add-on therapy to insulin in pregnancy with GDM or T2DM: A systematic review and meta-analysis of 21 randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Pregnant women are increasingly being exposed to metformin for conditions including gestational diabetes mellitus and type 2 diabetes mellitus. Metformin has been found to exhibit maternal to foetal transfer, and the long-term influence is uncertain. We conducted a meta-analysis to compare the efficacy and safety of metformin alone or as add-on therapy to insulin and insulin in pregnancy with gestational diabetes mellitus or type 2 diabetes mellitus.

METHODS

We performed a comprehensive literature search of PubMed, Embase, Cochrane Library and ClinicalTrials.gov for randomized controlled trials (RCTs) that compared metformin to insulin in pregnancy. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were used to synthesize the results. Two authors independently extracted the data, evaluated study quality and calculated pooled estimates.

RESULTS

Twenty-one studies involving 4,545 patients were included in this meta-analysis. Compared with insulin, metformin significantly reduced the risks of maternal weight gain [MD -1.51 kg, 95%CI (-1.90 kg, -1.12 kg), P < 0.00001], gestational age at birth [MD -0.12 week, 95%CI (-0.21 week, -0.02 week), P = 0.02], gestational hypertension [RR 0.63, 95%CI (0.48, 0.82), P = 0.0006], maternal hypoglycaemia [RR 0.33, 95%CI (0.15, 0.73), P = 0.006], birthweight [MD -0.13 kg, 95%CI (-0.20 kg, -0.07 kg), P < 0.0001], neonatal hypoglycaemia [RR 0.56, 95%CI (0.49, 0.64), P < 0.00001], neonatal intensive care unit admission [RR 0.73, 95%CI (0.64, 0.83), P < 0.00001], birthweight ≥4000 g [RR 0.70, 95%CI (0.59, 0.83), P < 0.0001], and large for gestational age [RR 0.83, 95%CI (0.72, 0.97), P = 0.02] and significantly increased the risk of small for gestational age [RR 1.43, 95%CI (1.08, 1.89), P = 0.01] in pregnancy.

WHAT IS NEW AND CONCLUSION

Metformin may have potential benefits for pregnant women and newborns in terms of maternal and foetal outcomes. More studies with long-term follow-up of offspring exposed to metformin in utero are needed to provide evidence for the future use of metformin in pregnancy.

Metformin Use in Gestational Diabetes: Awareness, Attitude, and Practice among Healthcare Professionals in Malaysia

Background:

Metformin has been added in the Malaysian clinical practice guideline (CPG) as one of the first-line options in the management of gestational diabetes mellitus (GDM); however, the uptake on this practice among healthcare professionals is unknown.

Objective:

The objective of the study is to determine the awareness, attitude, and practice and their predictors on the use of metformin for GDM among healthcare professionals in Malaysia.

Materials and Methods:

This was a multicenter, cross-sectional study in three tertiary hospitals in Malaysia. Medical doctors and pharmacists working in several departments were invited to participate in a survey using self-administered questionnaires.

Results:

From 350 questionnaires distributed, 225 were completed by medical doctors (43.1%), pharmacists (40.4%), and specialists (7.5%). Less than 30% of them were aware on the option of using metformin as one of the first-line agents in GDM. Education level, department, and profession were found to be associated with the awareness level (P = 0.016, P = 0.004, and P = 0.001, respectively). 70.2% of the respondents showed a positive attitude toward metformin use in GDM. Only 64 (28.4%) of the respondents have prescribed/dispensed metformin for GDM before, although more than half will consider doing so in the future. Having postgraduate qualifications increased the likelihood of having a good awareness (odds ratio [OR]: 2.44, 95% confidence interval [CI] 1.23–4.85) and to consider prescribing/dispensing metformin for GDM patients (OR: 2.27, 95% CI 1.08–4.78).

Conclusion:

Despite a positive attitude toward metformin use in GDM among healthcare professionals in Malaysia, their awareness level on this practice was low as they currently prefer the use of insulin over metformin.

Impact of metformin treatment during pregnancy on maternal outcomes: a systematic review/meta-analysis

We systematically assessed the impact of metformin treatment on maternal pregnancy outcomes. PubMed, Ovid Embase, Medline, Web of Science, ClinicalTrials.gov and Cochrane databases were systematically searched (inception-1st February 2021). Randomised controlled trials reporting pregnancy outcomes in women randomised to metformin versus any other treatment for any indication were included. Outcomes included gestational weight gain (GWG), pre-eclampsia, gestational hypertension, preterm birth, gestational age at delivery, caesarean section, gestational diabetes, glycaemic control, and gastrointestinal side-effects. Two independent reviewers conducted screening, with a third available to evaluate disagreements. Risk-of-bias and GRADE assessments were conducted using Cochrane Risk-of-Bias and GRADE-pro software. Thirty-five studies (n = 8033 pregnancies) met eligibility criteria. GWG was lower in pregnancies randomised to metformin versus other treatments (1.57 kg ± 0.60 kg; I₂ = 86%, p < 0.0001), as was likelihood of pre-eclampsia (OR 0.69, 95% CI 0.50-0.95; I₂ = 55%, p = 0.02). The risk of gastrointestinal side-effects was greater in metformin-exposed versus other treatment groups (OR 2.43, 95% CI 1.53-3.84; I₂ = 76%, p = 0.0002). The risk of other maternal outcomes assessed was not significantly different between metformin-exposed versus other treatment groups. Metformin for any indication during pregnancy is associated with lower GWG and a modest reduced risk of pre-eclampsia, but increased gastrointestinal side-effects compared to other treatments.

Treatment options of Adolescent Gestational Diabetes: Effect on Outcome

Objectives:

Teenage pregnancy with gestational diabetes mellitus (GDM) offers a real challenge to the health system and needs a special care. We aimed to evaluate possible obstetrical and neonatal adverse events of different treatment protocols in adolescent GDM including lifestyle, metformin (MTF), and insulin.

Methods:

All teen pregnant women ≤ 19 years old visiting Baghdad Teaching Hospital throughout four years (from June 1, 2016 till May 31, 2020) diagnosed with GDM were included in this cohort study and followed-up closely throughout pregnancy and after delivery. Included adolescents were put on lifestyle alone during the first week of presentation. Adolescents who reached target glucose measurements were categorized into lifestyle group, while other adolescents were randomly allocated into MTF and insulin groups. Also, adolescent pregnant women without GDM were recruited as control group using computer randomization.

Results:

The GDM (110 cases) and control (121 individuals) groups had matched general features at recruitment except for diabetes family history. Also, GDM treatment groups had matched features. Glycemic readings (fasting and random) was significantly (p< 0.05) higher in insulin group having odds ratio (OR) of 1.41, and 1.57, respectively. In MTF group, significant protective OR was found in preeclampsia (OR=0.76, p< 0.05). MTF showed non-significant protective OR regarding prematurity and five minutes Apgar score>7 [(OR=0.83, p=0.24), and (OR=0.94, p=0.73), respectively], and significant protective association with large for gestational age and admission to neonatal intensive unit. Insulin had significantly higher prematurity, small for gestational age, and hypoglycemia [OR=1.89, 2.53, and 2.84, respectively].

Conclusion:

Metformin (MTF) showed less pregnancy and neonatal complications in adolescent GDM than insulin and lifestyle.

Metformin is comparable to insulin for pharmacotherapy in gestational diabetes mellitus: A network meta-analysis evaluating 6046 women

CONTEXT

The comparative efficacy of gestational diabetes (GDM) treatments lack conclusive evidence for choice of first-line treatment.

OBJECTIVES

The aim of this study was to compare the efficacy of metformin and glibenclamide to insulin using a core outcome set (COS) to unify outcomes across trials investigating the treatment of gestational diabetes mellitus.

STUDY DESIGN

A network meta-analysis (NMA) was conducted.

DATA-SOURCE

PubMed, Embase, and Cochrane Controlled Register of Trials were searched from inception to January 2020.

STUDY SELECTION

RCTs that enrolled pregnant women who were diagnosed with GDM and that compared the efficacy of different pharmacological interventions for the treatment of GDM were included.

META-ANALYSIS

A generalized pairwise modelling framework was employed.

RESULTS

A total of 38 RCTs with 6046 participants were included in the network meta-analysis. Compared to insulin, the estimated effect of metformin indicated improvements for weight gain (WMD -2·39 kg; 95% CI -3·31 to -1·46), maternal hypoglycemia (OR 0.34; 95% CI 0.12 to 0·97) and LGA (OR 0.61; 95% CI 0.38 to 0·98). There were also improvements in estimated effects for neonatal hypoglycemia (OR 0.48; 95% CI 0.19 to 1·25), pregnancy induced hypertension (OR 0.63; 95% CI 0.37 to 1·06), and preeclampsia (OR 0.74; 95% CI 0.538 to 1·04), though with limited evidence against our model hypothesis of equivalence with insulin for these outcomes.

CONCLUSION

Metformin is, at least, comparable to insulin for the treatment of GDM. Glibenclamide appears less favorable, in comparison to insulin, than metformin.

The Effects of Altered Endometrial Glucose Homeostasis on Embryo Implantation in Type 2 Diabetic Mice

Type 2 diabetes mellitus (T2DM) is a disease characterized by hyperglycemia resulting from insulin resistance. In recent years, the incidence of T2DM has been increasing. Women with T2DM often suffer from infertility and early miscarriage; however, the underlying mechanisms remain unclear. Insulin is the most important regulatory hormone of glycogen metabolism. In addition, 5' adenosine monophosphate-activated protein kinase (AMPK) is an important regulator of glycogen metabolism. Patients with T2DM have inhibited AMPK expression in the liver, which leads to impaired glucose metabolism. However, the role of AMPK in endometrial glycogen metabolism has not been reported. In this study, a mouse model of T2DM was established to investigate whether altered endometrial glucose metabolism affects early embryo implantation. Metformin and insulin were used for therapy; the resulting changes to glycogen metabolism and embryo implantation were examined. The results indicate that the concentrations of glycogen decreased significantly in T2DM mice, resulting in insufficient energy supplies for proper endometrial function, and thereby impeding embryonic implantation. Interestingly, endometrial AMPK was not found to be overactivated. Insulin treatment was found to partially resolve the embryo implantation defects in T2DM mice. Metformin improved blood glucose but did not have a significant effect on local endometrial glucose metabolism. This study explored the changes in endometrial glucose metabolism in T2DM mouse, and the effects of these changes on embryo implantation. We found that insulin, but not metformin, significantly resolved embryo implantation problems. These findings will help to increase our understanding of the pathomechanisms of infertility and early miscarriage in women with T2DM.

Metformin versus insulin use for treatment of gestational diabetes and delivery by caesarean section: A nationwide Swedish cohort study

OBJECTIVE

Pregnant women who develop gestational diabetes (GDM) are more likely to deliver by caesarean section (CS). Over the last decade, the use of metformin has increased as an alternative to insulin but it's unknown how this shift in treatment has influenced the mode of delivery. Therefore, the aim of this study was to determine the association between metformin use and CS and delivery of a large-for-gestational age (LGA) infant compared to insulin use for GDM.

STUDY DESIGN

The Swedish population health registers were linked to identify pregnant women from 2012 to 2016 without preexisting diabetes and with a first filled prescription of insulin or metformin in trimester 2 or 3 (n = 2467), categorized into those treated with insulin only (88%), metformin only (7.6%), or both insulin and metformin (4.3%). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Analyses were adjusted for relevant covariates and stratified by history of CS.

RESULTS

The proportion of women using metformin to treat GDM increased from 2.5% in 2012 to over 30% in 2016. Comparing insulin only to metformin only use, no association with delivery by CS (adjusted OR 0.79, 95% CI; 0.54-1.16) and lower odds of delivering a LGA infant (adjusted OR 0.44, 95% CI; 0.26-0.76) was found. Treatment with both insulin and metformin was associated with an increased risk of CS (adjusted OR 1.65, 95% CI; 1.06-2.56), which were more often unplanned. Estimates were further elevated in nulliparous (adjusted OR 2.32, 95% CI; 0.95-5.65) and multiparous women with a history of CS (adjusted OR 2.29, 95% CI; 0.60-8.74) but conclusions could not be drawn given the wide CIs.

CONCLUSION

There was no evidence of a higher association of metformin use alone with CS compared to insulin use for treatment of GDM but a protective effect for delivery of a LGA infant was shown. Women requiring treatment with both insulin and metformin had increased odds for delivery by CS which in turn may indicate that the need for the use of both medications to treat GDM suggests a pregnancy at higher risk.

Metformin in Pregnancy Study (MiPS): protocol for a systematic review with individual patient data meta-analysis

INTRODUCTION

Gestational diabetes mellitus (GDM) is a common disorder of pregnancy and contributes to adverse pregnancy outcomes. Metformin is often used for the prevention and management of GDM; however, its use in pregnancy continues to be debated. The Metformin in Pregnancy Study aims to use individual patient data (IPD) meta-analysis to clarify the efficacy and safety of metformin use in pregnancy and to identify relevant knowledge gaps.

METHODS AND ANALYSIS

MEDLINE, EMBASE and all Evidence-Based Medicine will be systematically searched for randomised controlled trials (RCT) testing the efficacy of metformin compared with placebo, usual care or other interventions in pregnant women. Two independent reviewers will assess eligibility using prespecified criteria and will conduct data extraction and quality appraisal of eligible studies. Authors of included trials will be contacted and asked to contribute IPD. Primary outcomes include maternal glycaemic parameters and GDM, as well as neonatal hypoglycaemia, anthropometry and gestational age at delivery. Other adverse maternal, birth and neonatal outcomes will be assessed as secondary outcomes. IPD from these RCTs will be harmonised and a two-step meta-analytic approach will be used to determine the efficacy and safety of metformin in pregnancy, with a priori adjustment for covariates and subgroups to examine effect moderators of treatment outcomes. Sensitivity analyses will assess heterogeneity, risk of bias and the impact of trials which have not provided IPD.

ETHICS AND DISSEMINATION

All IPD will be deidentified and studies contributing IPD will have ethical approval from their respective local ethics committees. This study will provide robust evidence regarding the efficacy and safety of metformin use in pregnancy, and may identify subgroups of patients who may benefit most from this treatment modality. Findings will be published in peer-reviewed journals and disseminated at scientific meetings, providing much needed evidence to inform clinical and public health actions in this area.

Comparative impact of pharmacological treatments for gestational diabetes on neonatal anthropometry independent of maternal glycaemic control: A systematic review and meta-analysis

BACKGROUND

Fetal growth in gestational diabetes mellitus (GDM) is directly linked to maternal glycaemic control; however, this relationship may be altered by oral anti-hyperglycaemic agents. Unlike insulin, such drugs cross the placenta and may thus have independent effects on fetal or placental tissues. We investigated the association between GDM treatment and fetal, neonatal, and childhood growth.

METHODS AND FINDINGS

PubMed, Ovid Embase, Medline, Web of Science, ClinicalTrials.gov, and Cochrane databases were systematically searched (inception to 12 February 2020). Outcomes of GDM-affected pregnancies randomised to treatment with metformin, glyburide, or insulin were included. Studies including preexisting diabetes or nondiabetic women were excluded. Two reviewers independently assessed eligibility and risk of bias, with conflicts resolved by a third reviewer. Maternal outcome measures were glycaemic control, weight gain, and treatment failure. Offspring anthropometric parameters included fetal, neonatal, and childhood weight and body composition data. Thirty-three studies (n = 4,944), from geographical locations including Europe, North Africa, the Middle East, Asia, Australia/New Zealand, and the United States/Latin America, met eligibility criteria. Twenty-two studies (n = 2,801) randomised women to metformin versus insulin, 8 studies (n = 1,722) to glyburide versus insulin, and 3 studies (n = 421) to metformin versus glyburide. Eleven studies (n = 2,204) reported maternal outcomes. No differences in fasting blood glucose (FBS), random blood glucose (RBS), or glycated haemoglobin (HbA1c) were reported. No studies reported fetal growth parameters. Thirty-three studies (n = 4,733) reported birth weight. Glyburide-exposed neonates were heavier at birth (58.20 g, 95% confidence interval [CI] 10.10-106.31, p = 0.02) with increased risk of macrosomia (odds ratio [OR] 1.38, 95% CI 1.01-1.89, p = 0.04) versus neonates of insulin-treated mothers. Metformin-exposed neonates were born lighter (-73.92 g, 95% CI -114.79 to -33.06 g, p < 0.001) with reduced risk of macrosomia (OR 0.60, 95% CI 0.45-0.79, p < 0.001) than insulin-exposed neonates. Metformin-exposed neonates were born lighter (-191.73 g, 95% CI -288.01 to -94.74, p < 0.001) with a nonsignificant reduction in macrosomia risk (OR 0.32, 95% CI 0.08-1.19, I2 = 0%, p = 0.09) versus glyburide-exposed neonates. Glyburide-exposed neonates had a nonsignificant increase in total fat mass (103.2 g, 95% CI -3.91 to 210.31, p = 0.06) and increased abdominal (0.90 cm, 95% CI 0.03-1.77, p = 0.04) and chest circumferences (0.80 cm, 95% CI 0.07-1.53, p = 0.03) versus insulin-exposed neonates. Metformin-exposed neonates had decreased ponderal index (-0.13 kg/m3, 95% CI -0.26 to -0.00, p = 0.04) and reduced head (-0.21, 95% CI -0.39 to -0.03, p = 0.03) and chest circumferences (-0.34 cm, 95% CI -0.62 to -0.05, p = 0.02) versus the insulin-treated group. Metformin-exposed neonates had decreased ponderal index (-0.09 kg/m3, 95% CI -0.17 to -0.01, p = 0.03) versus glyburide-exposed neonates. Study limitations include heterogeneity in dosing, heterogeneity in GDM diagnostic criteria, and few studies reporting longitudinal growth outcomes.

CONCLUSIONS

Maternal randomisation to glyburide resulted in heavier neonates with a propensity to increased adiposity versus insulin- or metformin-exposed groups. Metformin-exposed neonates were lighter with reduced lean mass versus insulin- or glyburide-exposed groups, independent of maternal glycaemic control. Oral anti-hyperglycaemics cross the placenta, so effects on fetal anthropometry could result from direct actions on the fetus and/or placenta. We highlight a need for further studies examining the effects of intrauterine exposure to antidiabetic agents on longitudinal growth, and the importance of monitoring fetal growth and maternal glycaemic control when treating GDM. This review protocol was registered with PROSPERO (CRD42019134664/CRD42018117503).

Association between insulin and post-caesarean resuscitation rates in infants of women with GDM: A retrospective study

BACKGROUND

Gestational diabetes mellitus (GDM) and caesarean deliveries independently increase the risk of postoperative complications. There are limited data on the influence of insulin use on the outcomes of neonates who were delivered via caesarean section. We sought to investigate the impact of insulin use in women with GDM on resuscitation rates of infants post caesarean delivery.

METHODS

A retrospective database review of women with singleton term (≥ 37 weeks) pregnancies who were on insulin for GDM delivering between January 2005 and December 2014 at a major metropolitan hospital in Sydney.

RESULTS

One thousand eight hundred and fifty-seven women with GDM were identified. The mean age was 31.01 ± 5.63 years and mean gestational period of 39.07 ± 1.00 weeks. 31.0% received insulin treatment for GDM. Women who were on insulin were older (31.9 ± 5.7 vs 30.6 ± 5.6 years, P < 0.001), had a higher body mass index (BMI) (31.2 ± 7.7 vs 29.0 ± 7.4 kg/m2, P < 0.001), higher rates of preeclampsia (7.3% vs 4.1%, P = 0.004), lower rates of alcohol consumption (0.4% vs 1.7%, P = 0.014), and had infants with lower resuscitation rates (21.2% vs 28.6%, P = 0.001). Infants who required resuscitation had a lower gestational age, lower five-minute APGAR score, and lower birth weight, length, and head circumferences. On multivariate analysis, women with GDM treated with insulin (odds ratio [OR] = 0.69, CI = 0.54-0.89, P = 0.004), higher gestational age (OR = 0.88, CI = 0.78-0.99, P = 0.032), higher maternal BMI (OR = 1.02, CI = 1.01-1.04, P = 0.005), and emergency caesarean (OR = 2.33, CI = 1.74-3.12, P < 0.001) independently predicted incidence of resuscitation.

CONCLUSIONS

The findings suggest a relationship between insulin use and reduced resuscitation rates of infants born from mothers with GDM. Further studies investigating the role, dosage, and criteria for insulin use in women with GDM are required.

Metformin versus insulin for gestational diabetes: a systematic review and meta-analysis

BACKGROUND

Metformin is increasingly used in clinical practice for the treatment of gestational diabetes mellitus. However, its safety and long-term effects on fetuses exposed to metformin in uterus remain controversial.

METHODS

We systematically searched PubMed, Embase, and the Cochrane database (last search was updated on 1 May 2019) for randomized controlled trials comparing metformin with insulin. Two reviewers extracted the data and calculated pooled estimates by use of a random-effects model.

RESULTS

Twenty-four studies were included. Among these, seventeen RCTs (N = 2828 participants) were included for quantitative analyses and seven studies were included only for qualitative synthesis. Metformin lowered the risk of pregnancy-induced hypertension (p = .03; risk ratio (RR) = 0.64; confidence interval (95%CI) [0.44, 0.95]), large for gestational age babies (p = .04; RR = 0.82; 95% CI [0.68, 0.99]), macrosomia (p = .01; RR = 0.63; 95%CI [0.45, 0.90]), neonatal hypoglycemia (p = .001; RR = 0.72; 95%CI [0.59, 0.88]), and neonatal intensive care unit admission (p = .01; RR = 0.74; 95%CI [0.58, 0.94]). Metformin did not increase premature delivery (p = .11; RR = 1.28; 95%CI [0.95, 1.73]), preeclampsia (p = .45; RR = 0.89; 95%CI [0.65, 1.21]), caesarean delivery (p = .20; RR = 0.94; 95%CI [0.85, 1.04]), small for gestational age babies (p = .95; RR = 0.99; 95%CI [0.69, 1.42]). The long-term results seemed to have no adverse effect, but the information was still limited.

CONCLUSIONS

According to our review, metformin may have potential benefits for pregnant women and newborns with no obvious adverse effects. However, even more studies are needed to provide evidence for the future use of metformin.

[Gestational diabetes mellitus (Update 2019)]

Gestational diabetes mellitus (GDM) is defined as a glucose tolerance disorder with onset during pregnancy and is associated with increased feto-maternal morbidity as well as long-term complications in mother and child. Women who fulfil the criteria of a manifest diabetes in early pregnancy (fasting plasma glucose >126 mg/dl, spontaneous glucose level >200 mg/dl or HbA1c > 6.5% before 20 weeks of gestation) should be classified as having manifest diabetes in pregnancy and treated as such. Screening for undiagnosed type 2 diabetes at the first prenatal visit (evidence level B) is particularly recommended in women at increased risk (history of GDM or prediabetes, malformation, stillbirth, successive abortions or birth weight >4500 g in previous pregnancies, obesity, metabolic syndrome, age >35 years, vascular disease, clinical symptoms of diabetes, e. g. glucosuria, or ethnic groups with increased risk for GDM/T2DM, e.g. Arabian countries, south and southeast Asia and Latin America). A GDM is diagnosed by an oral glucose tolerance test (OGTT) or a fasting glucose concentration ≥92 mg/dl. Performance of the OGTT (120 min, 75 g glucose) may already be indicated in the first trimester in high risk women but is mandatory between 24-28 gestational weeks in all pregnant women with previous non-pathological glucose metabolism (evidence level B). Based on the results of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study and following the recent WHO recommendations, GDM is present if the fasting plasma glucose level exceeds 92 mg/dl, the 1 h level exceeds 180 mg/dl or the 2 h level exceeds 153 mg/dl after glucose loading (OGTT international consensus criteria). A single increased value is sufficient for the diagnosis and a strict metabolic control is mandatory. After bariatric surgery an OGTT is not recommended due to the risk of postprandial hypoglycemia. All women with GDM should receive nutritional counselling, be instructed in self-monitoring of blood glucose and to increase physical activity to moderate intensity levels, if not contraindicated. If blood glucose levels cannot be maintained in the therapeutic range (fasting <95 mg/dl and 1 h postprandial <140 mg/dl) insulin therapy should be initiated as first choice. Maternal and fetal monitoring is required in order to minimize maternal and fetal/neonatal morbidity and perinatal mortality. After delivery all women with GDM have to be re-evaluated by a 75 g OGTT (WHO criteria) 4-12 weeks postpartum to reclassify the glucose tolerance and every 2 years in cases of normal glucose tolerance (evidence level B). All women have to be informed about their (sevenfold increased relative) risk of developing type 2 diabetes (T2DM) at follow-up and possible preventive measures, in particular weight management, healthy diet and maintenance/increase of physical activity. Monitoring of the development of children and recommendations for a healthy lifestyle are necessary for the whole family. Regular obstetric examinations including ultrasound examinations are recommended. Within the framework of neonatal care, neonates of GDM mothers should undergo blood glucose measurements and if necessary appropriate measures should be initiated.

Neonatal, infant, and childhood growth following metformin versus insulin treatment for gestational diabetes: A systematic review and meta-analysis

BACKGROUND

Metformin is increasingly offered as an acceptable and economic alternative to insulin for treatment of gestational diabetes mellitus (GDM) in many countries. However, the impact of maternal metformin treatment on the trajectory of fetal, infant, and childhood growth is unknown.

METHODS AND FINDINGS

PubMed, Ovid Embase, Medline, Web of Science, ClinicalTrials.gov, and the Cochrane database were systematically searched (from database inception to 26 February 2019). Outcomes of GDM-affected pregnancies randomised to treatment with metformin versus insulin were included (randomised controlled trials and prospective randomised controlled studies) from cohorts including European, American, Asian, Australian, and African women. Studies including pregnant women with pre-existing diabetes or non-diabetic women were excluded, as were trials comparing metformin treatment with oral glucose-lowering agents other than insulin. Two reviewers independently assessed articles for eligibility and risk of bias, and conflicts were resolved by a third reviewer. Outcome measures were parameters of fetal, infant, and childhood growth, including weight, height, BMI, and body composition. In total, 28 studies (n = 3,976 participants) met eligibility criteria and were included in the meta-analysis. No studies reported fetal growth parameters; 19 studies (n = 3,723 neonates) reported measures of neonatal growth. Neonates born to metformin-treated mothers had lower birth weights (mean difference -107.7 g, 95% CI -182.3 to -32.7, I2 = 83%, p = 0.005) and lower ponderal indices (mean difference -0.13 kg/m3, 95% CI -0.26 to 0.00, I2 = 0%, p = 0.04) than neonates of insulin-treated mothers. The odds of macrosomia (odds ratio [OR] 0.59, 95% CI 0.46 to 0.77, p < 0.001) and large for gestational age (OR 0.78, 95% CI 0.62 to 0.99, p = 0.04) were lower following maternal treatment with metformin compared to insulin. There was no difference in neonatal height or incidence of small for gestational age between groups. Two studies (n = 411 infants) reported measures of infant growth (18-24 months of age). In contrast to the neonatal phase, metformin-exposed infants were significantly heavier than those in the insulin-exposed group (mean difference 440 g, 95% CI 50 to 830, I2 = 4%, p = 0.03). Three studies (n = 520 children) reported mid-childhood growth parameters (5-9 years). In mid-childhood, BMI was significantly higher (mean difference 0.78 kg/m2, 95% CI 0.23 to 1.33, I2 = 7%, p = 0.005) following metformin exposure than following insulin exposure, although the difference in absolute weights between the groups was not significantly different (p = 0.09). Limited evidence (1 study with data treated as 2 cohorts) suggested that adiposity indices (abdominal [p = 0.02] and visceral [p = 0.03] fat volumes) may be higher in children born to metformin-treated compared to insulin-treated mothers. Study limitations include heterogeneity in metformin dosing, heterogeneity in diagnostic criteria for GDM, and the scarcity of reporting of childhood outcomes.

CONCLUSIONS

Following intrauterine exposure to metformin for treatment of maternal GDM, neonates are significantly smaller than neonates whose mothers were treated with insulin during pregnancy. Despite lower average birth weight, metformin-exposed children appear to experience accelerated postnatal growth, resulting in heavier infants and higher BMI by mid-childhood compared to children whose mothers were treated with insulin. Such patterns of low birth weight and postnatal catch-up growth have been reported to be associated with adverse long-term cardio-metabolic outcomes. This suggests a need for further studies examining longitudinal perinatal and childhood outcomes following intrauterine metformin exposure. This review protocol was registered with PROSPERO under registration number CRD42018117503.

Gestational diabetes mellitus

Hyperglycaemia that develops during pregnancy and resolves after birth has been recognized for over 50 years, but uniform worldwide consensus is lacking about threshold hyperglycaemic levels that merit a diagnosis of 'gestational diabetes mellitus' (GDM) and thus treatment during pregnancy. GDM is currently the most common medical complication of pregnancy, and prevalence of undiagnosed hyperglycaemia and even overt diabetes in young women is increasing. Maternal overweight and obesity, later age at childbearing, previous history of GDM, family history of type 2 diabetes mellitus and ethnicity are major GDM risk factors. Diagnosis is usually performed using an oral glucose tolerance test (OGTT), although a non-fasting, glucose challenge test (GCT) is used in some parts of the world to screen women for those requiring a full OGTT. Dietary modification and increased physical activity are the primary treatments for GDM, but pharmacotherapy, usually insulin, is used when normoglycaemia is not achieved. Oral hypoglycaemic agents, principally metformin and glibenclamide (glyburide), are also used in some countries. Treatment improves immediate pregnancy outcomes, reducing excess fetal growth and adiposity and pregnancy-related hypertensive disorders. GDM increases the risk of long-term complications, including obesity, impaired glucose metabolism and cardiovascular disease, in both the mother and infant. Optimal management of mother and infant during long-term follow-up remains challenging, with very limited implementation of preventive strategies in most parts of the world.

Long-term effects of prenatal exposure to metformin on the health of children based on follow-up studies of randomized controlled trials: a systematic review and meta-analysis

PURPOSE

Oral antidiabetic medication of metformin is increasingly used in pregnant women with gestational diabetes mellitus (GDM), polycystic ovary syndrome (PCOS) and obesity. The drug passes through the placenta and can potentially influence the fetus. The aim of the study is to investigate the possible long-term effects of prenatal exposure to metformin on growth and development of the offspring.

METHODS

A systematic review and meta-analysis was conducted to examine the longer term outcomes by the follow-up studies of the already published RCTs focusing on the body composition, metabolic parameters and neurophysiological development of the children prenatally exposed to metformin. The primary sources of the reviewed studies through August 2018, with restriction on the language of English, were Pubmed and Embase.

RESULTS

11 follow-up studies were included, with a maximal age of children being 13 years, comprising 823 children of mothers with GDM or PCOS who were randomized to either metformin or insulin/placebo during pregnancy. From the pooled meta-analysis we found that children prenatal exposure to metformin were associated with a significantly heavier weight (MD = 0.48 kg, 95% CI 0.24 kg, 0.73 kg; P = 0.0001, I² = 0). As for other parameters of body composition, metabolic parameters and neurophysiological development, the results were similar between metformin and placebo/insulin use.

CONCLUSION

Increased offspring weight was more observed in children prenatal exposure to metformin. Heathcare providers and patients should be aware that metformin is increasingly prescribed in pregnancy based on the relatively limited evidences but nonetheless encouraging long-term offspring data are available.

Anti-inflammatory Action of Metformin with Respect to CX3CL1/CX3CR1 Signaling in Human Placental Circulation in Normal-Glucose Versus High-Glucose Environments

Upregulation of chemokine CX3CL1 and its receptor CX3CR1 occurs in the diabetic human placenta. Metformin, an insulin-sensitizing biguanide, is used in the therapy of diabetic pregnancy. By preventing the activation of NF-κB, metformin exhibits anti-inflammatory properties. We examined the influence of hyperglycemia (25 mmol/L glucose; HG group; N = 36) on metformin-mediated effects on CX3CL1 and TNF-α production by placental lobules perfused extracorporeally. Additionally, CX3CR1 expression and contents of CX3CR1, TNF-α receptor 1 (TNFR1), and NF-κB proteins in the placental tissue were evaluated. Placentae perfused under normoglycemia (5 mmol/L glucose; NG group; N = 36) served as the control. Metformin (2.5 and 5.0 mg/L; subgroups B and C) lowered the production of CX3CL1 and TNF-α in a dose-dependent and time-dependent manner. Hyperglycemia did not weaken the strength of these metformin effects. Moreover, CX3CL1 levels after perfusion with 5.0 mg/L metformin were reduced by 33.28 and 33.83% (at 120 and 150 min, respectively) in the HG-C subgroup versus 24.98 and 23.66% in the NG-C subgroup, which indicated an augmentation of the metformin action over time in hyperglycemia. CX3CR1 expression was significantly higher in the HG-B and HG-C subgroups compared to that in the NG-B and NG-C subgroups. Increased CX3CR1 protein content in the placental lysates was observed in subgroups B and C. The two higher metformin concentrations significantly decreased the levels of NF-κBp65 protein content in both groups. However, the decrease was significantly stronger in hyperglycemia. TNFR1 upregulation in the HG group was not affected by metformin. Further studies on metformin therapy during pregnancy are needed, including safety issues.

Comparative Efficacy and Safety of Metformin, Glyburide, and Insulin in Treating Gestational Diabetes Mellitus: A Meta-Analysis

To compare the efficacy and safety of metformin, glyburide, and insulin in treating gestational diabetes mellitus (GDM), a meta-analysis of randomized controlled trials (RCTs) was conducted. PubMed, Embase, CINAHL, Web of Science, and Cochrane Library to November 13, 2018, were searched for RCT adjusted estimates of the efficacy and safety of metformin, glyburide, and insulin treatments in GDM patients. There were 41 studies involving 7703 GDM patients which were included in this meta-analysis; 12 primary outcomes and 24 secondary outcomes were detected and analyzed. Compared with metformin, insulin had a significant increase in the risk of preeclampsia (RR, 0.57; 95% CI, 0.45 to 0.72; P < 0.001), NICU admission (RR, 0.75; 95% CI, 0.64 to 0.87; P < 0.001), neonatal hypoglycemia (RR, 0.57; 95% CI, 0.49 to 0.66; P < 0.001), and macrosomia (RR, 0.68; 95% CI, 0.55 to 0.86; P < 0.05). To the outcomes of birth weight and gestational age at delivery, insulin had a significant increase when compared with metformin (MD, 114.48; 95% CI, 37.32 to 191.64; P < 0.01; MD, 0.23; 95% CI, 0.12 to 0.34; P < 0.001; respectively). Of the two groups between glyburide and metformin, metformin had lower gestational weight gain compared with glyburide (MD, 1.67; 95% CI, 0.26 to 3.07; P < 0.05). Glyburide had a higher risk of neonatal hypoglycemia compared with insulin (RR, 1.76; 95% CI, 1.32 to 2.36; P < 0.001). This meta-analysis found that metformin could be a safe and effective treatment for GDM. However, clinicians should pay attention on the long-term offspring outcomes of the relative data with GDM patients treated with metformin. Compared with insulin, glyburide had a higher increase of neonatal hypoglycemia. The use of glyburide in pregnancy for GDM women appears to be unclear.

Metformin for prevention of hypertensive disorders of pregnancy in women with gestational diabetes or obesity: systematic review and meta-analysis of randomized trials

OBJECTIVE

Metformin has been reported to reduce the risk of pre-eclampsia. It is also known to influence soluble fms-like tyrosine kinase-1 level, which correlates significantly with the gestational age at onset and severity of pre-eclampsia. The main aim of this systematic review and meta-analysis of randomized trials was to determine whether metformin use is associated with the incidence of hypertensive disorders of pregnancy (HDP).

METHODS

MEDLINE (1947 to September 2017), Scopus (1970 to September 2017) and the Cochrane Library (inception to September 2017) were searched for relevant citations in the English language. Only randomized controlled trials on metformin use, reporting the incidence of pre-eclampsia or pregnancy-induced hypertension, were included. Studies on populations with a high probability of metformin use prior to randomization (those with type II diabetes or polycystic ovary syndrome) were excluded. Random-effects models with the Mantel-Haenszel method were used for subgroup analyses. Bayesian random-effects meta-regression was used to summarize the evidence.

RESULTS

In total, 3337 citations matched the search criteria. After evaluating 2536 abstracts and performing full-text review of 52 studies, 15 were included in the review. In women with gestational diabetes, metformin use was associated with a reduced risk of pregnancy-induced hypertension when compared with insulin (relative risk (RR), 0.56; 95% CI, 0.37-0.85; I²  = 0%; 1260 women) and a non-significantly reduced risk of pre-eclampsia (RR, 0.83; 95% CI, 0.60-1.14; I²  = 0%; 1724 women). In obese women, when compared with placebo, metformin use was associated with a non-significant reduction in risk of pre-eclampsia (RR, 0.74; 95% CI, 0.09-6.28; I²  = 86%; 840 women). In women with gestational diabetes, metformin use was also associated with a non-significant reduction in risk of any HDP (RR, 0.71; 95% CI, 0.41-1.25; I²  = 0%; 556 women) when compared with glyburide. When studies were combined using Bayesian random-effects meta-regression, with treatment type as a covariate, the posterior probabilities of metformin having a beneficial effect on the prevention of pre-eclampsia, pregnancy-induced hypertension and any HDP were 92.7%, 92.8% and 99.2%, respectively, when compared with any other treatment or placebo.

CONCLUSIONS

There is a high probability that metformin use is associated with reduced HDP incidence when compared with other treatments or placebo. The small number of studies included in the analysis, the low quality of evidence and the clinical heterogeneity preclude generalization of these results to broader populations. Given the clinical importance of this topic and the magnitude of effect observed in this meta-analysis, further prospective trials are urgently needed. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

AMP-Activated Protein (AMPK) in Pathophysiology of Pregnancy Complications

Although the global maternal mortality ratio has been consistently reduced over time, in 2015, there were still 303,000 maternal deaths throughout the world, of which 99% occurred in developing countries. Understanding pathophysiology of pregnancy complications contributes to the proper prenatal care for the reduction of prenatal, perinatal and neonatal mortality and morbidity ratio. In this review, we focus on AMP-activated protein kinase (AMPK) as a regulator of pregnancy complications. AMPK is a serine/threonine kinase that is conserved within eukaryotes. It regulates the cellular and whole-body energy homeostasis under stress condition. The functions of AMPK are diverse, and the dysregulation of AMPK is known to correlate with many disorders such as cardiovascular disease, diabetes, inflammatory disease, and cancer. During pregnancy, AMPK is necessary for the proper placental differentiation, nutrient transportation, maternal and fetal energy homeostasis, and protection of the fetal membrane. Activators of AMPK such as 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR), resveratrol, and metformin restores pregnancy complications such as gestational diabetes mellitus (GDM), preeclampsia, intrauterine growth restriction, and preterm birth preclinically. We also discuss on the relationship between catechol-O-methyltransferase (COMT), an enzyme that metabolizes catechol, and AMPK during pregnancy. It is known that metformin cannot activate AMPK in COMT deficient mice, and that 2-methoxyestradiol (2-ME), a metabolite of COMT, recovers the AMPK activity, suggesting that COMT is a regulator of AMPK. These reports suggest the therapeutic use of AMPK activators for various pregnancy complications, however, careful analysis is required for the safe use of AMPK activators since AMPK activation could cause fetal malformation.

Long-Term Effects of Oral Antidiabetic Drugs During Pregnancy on Offspring: A Systematic Review and Meta-analysis of Follow-up Studies of RCTs

INTRODUCTION

Antidiabetic drugs (OADs) are increasingly prescribed to treat hyperglycaemia during pregnancy in women with gestational diabetes mellitus (GDM) or polycystic ovary syndrome (PCOS), even though long-term effects on offspring are unknown. This systematic review summarises the evidence of follow-up studies of randomised controlled trials (RCTs) reporting on long-term effects of prenatal exposure to OADs on offspring.

METHODS

The MEDLINE, EMBASE and CENTRAL databases were searched from inception to April 2018 for the concepts antidiabetic agents and prenatal exposure (or pregnancy and offspring/child) in combination with an RCT search filter. RCTs evaluating post-neonatal health effects in offspring and comparing maternal treatment with an OAD with no treatment, placebo, an alternative OAD or insulin during pregnancy were eligible for inclusion. Two independent researchers selected, extracted and assessed the data. Meta-analyses were performed using a random effects model and the Cochrane Collaboration's risk of bias tool was used for quality assessment.

RESULTS

Ten studies were included, with a maximal follow-up duration of 9 years, comprising 778 children of mothers with GDM or PCOS who were randomised to either metformin or insulin/placebo during pregnancy. Meta-analysis showed that children prenatally exposed to metformin were heavier compared to controls (standardised mean difference (SMD) 0.26 [95% CI 0.11-0.41]), but not taller (SMD 0.10 [95% CI -0.14-0.33]). Additionally, offspring body mass index (BMI) z scores did not differ according to metformin exposure (mean difference 0.30 [95% CI -0.01-0.61]). Individual small studies reported that prenatal exposure to metformin was associated with greater mid-upper arm, head and waist circumferences, biceps skinfolds, waist-to-height ratio, more arm fat, higher fasting glucose, ferritin and lower LDL cholesterol in offspring.

CONCLUSION

Prenatal exposure to metformin is associated with increased offspring weight, but not with height or BMI. Larger follow-up studies are needed to confirm and look into the implications of these findings. Plain language summary available for this article.

Oral Agents for the Treatment of Gestational Diabetes

PURPOSE OF REVIEW

To review the current evidence of the safety and efficacy of the use of oral agents for treatment of gestational diabetes (GDM).

RECENT FINDINGS

The use of metformin and glyburide in pregnancy for treatment of GDM has dramatically increased since the early 2000s. Meta-analyses suggest that glyburide may increase the risk for large for gestational (LGA) infants and neonatal hypoglycemia. Conversely, metformin may potentially decrease rates of pregnancy-induced hypertension, LGA, neonatal hypoglycemia, and maternal weight gain. However, recent long-term offspring studies indicate a potential detrimental effect of metformin on fat mass that suggests an effect of such medication on fetal programming. While there have been several novel oral anti-diabetes medications brought to market in the past decade, there is minimal data to guide use and in particular data regarding long-term safety for the exposed offspring of treated women. Most professional societies recommend insulin as first-line treatment of gestational diabetes after failure of lifestyle modification. Both metformin and glyburide cross the placenta and long-term safety data is limited. However, patient satisfaction is substantially higher with use of oral agents, and the current literatures suggest that metformin may reduce several common short-term adverse outcomes related to GDM.

The efficacy of metformin compared with insulin in regulating blood glucose levels during gestational diabetes mellitus: A randomized clinical trial

BACKGROUND

Insulin has been a conventional medication in the treatment of female patients suffering from gestational diabetes mellitus (GDM). However, the need for a large number of insulin injections in these patients causes them a lot of discomforts. Recently, an alternative medication, metformin, has received considerable attention in the treatment of GDM. The aim of this study was to compare the efficacy of metformin and insulin in regulating blood glucose levels and fetal outcomes in GDM.

METHODS

This randomized clinical trial included 286 pregnant women diagnosed with positive GDM at 24-28 weeks of pregnancy. The subjects were randomly divided into two groups of 143 patients, with one group receiving insulin and the other undergoing a treatment plan using metformin. Fasting plasma glucose (FPG), 2-hr plasma glucose (PG) and glycated hemoglobin (HbA1c) were recorded twice a month until delivery. Other variables, including birth delivery method, cause of cesarean section, gestational age at the delivery time, birth trauma, Apgar score, birth weight, admission at neonatal intensive care unit (NICU), and neonatal hypoglycemia were also registered.

RESULTS

Age of mother, body mass index, history of diabetes in the family, previous history of GDM, parity, FPG, 1- and 2-hr PG after meals, and 75-g glucose tolerance test before treatment were not statistically different between the two groups. FPG, PG, and HbA1c did not show significant differences between the two groups after completing the course of treatment. There was also no significant difference between two groups regarding the birth delivery method, the cause of cesarean section, birth trauma, Apgar score, birth weight, admission at NICU, and neonatal hypoglycemia.

CONCLUSION

As mean FPG and 2-hr PG were not significantly different between the two groups, it seems that metformin can be recommended as an effective substitute for insulin in the treatment of GDM. However, there are still some undesirable risk factors with both treatments that may threaten the mother and the newborn.