The role of continuing metformin therapy during pregnancy in the reduction of gestational diabetes and improving pregnancy outcomes in women with polycystic ovary syndrome

Metformin administration during pregnancy tends to reduce the risk of gestational diabetes mellitus and improve pregnancy outcomes in previously infertile women with polycystic ovary syndrome who become pregnant

OBJECTIVE

Metformin reduces incidences of miscarriage and preterm delivery in polycystic ovary syndrome (PCOS) women, but its impact on gestational diabetes mellitus (GDM) is conflicting. Hence, this study set up selection criteria to include previously infertile women with PCOS but without pre-existing DM who became pregnant, aiming to minimize confounders and investigate the influence of metformin on GDM, miscarriage, and preterm delivery.

METHODS

This study included 195 previously infertile women with PCOS who became pregnant. They were divided into metformin (receiving metformin during pregnancy) and control (not receiving metformin) groups without intervention.

RESULTS

Metformin group tended to have a lower incidence of GDM versus control group (13.3% versus 23.3%, P = 0.070). A logistic regression model adjusted for all baseline characteristics (demographics, infertile duration, and diabetes mellitus-related features) showed that metformin was associated with a decreased probability of GDM (odds ratio (OR): 0.426, P = 0.037). Metformin group showed a similar incidence of miscarriage (6.7% versus 11.1%, P = 0.273), but decreased incidences of preterm delivery (not statistically significant) (6.7% versus 13.3%, P = 0.091) and miscarriage or preterm delivery (13.3% versus 24.4%, P = 0.046) versus control group. A logistic regression model adjusted for all the aforementioned features revealed that metformin was related to a lower risk of miscarriage or preterm delivery (OR: 0.417, P = 0.040). Fetal outcomes, including birth weight (P = 0.245) and the incidence of 5 min-Apgar score ≤ 7 (P = 0.702), were similar between groups.

CONCLUSION

Metformin administration during pregnancy may reduce GDM, miscarriage, and preterm delivery risks without adverse effects on fetal outcomes in previously infertile women with PCOS.

Effective interventions in preventing gestational diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Lifestyle choices, metformin, and dietary supplements may prevent GDM, but the effect of intervention characteristics has not been identified. This review evaluated intervention characteristics to inform the implementation of GDM prevention interventions.

METHODS

Ovid, MEDLINE/PubMed, and EMBASE databases were searched. The Template for Intervention Description and Replication (TIDieR) framework was used to examine intervention characteristics (who, what, when, where, and how). Subgroup analysis was performed by intervention characteristics.

RESULTS

116 studies involving 40,940 participants are included. Group-based physical activity interventions (RR 0.66; 95% CI 0.46, 0.95) reduce the incidence of GDM compared with individual or mixed (individual and group) delivery format (subgroup p-value = 0.04). Physical activity interventions delivered at healthcare facilities reduce the risk of GDM (RR 0.59; 95% CI 0.49, 0.72) compared with home-based interventions (subgroup p-value = 0.03). No other intervention characteristics impact the effectiveness of all other interventions.

CONCLUSIONS

Dietary, physical activity, diet plus physical activity, metformin, and myoinositol interventions reduce the incidence of GDM compared with control interventions. Group and healthcare facility-based physical activity interventions show better effectiveness in preventing GDM than individual and community-based interventions. Other intervention characteristics (e.g. utilization of e-health) don't impact the effectiveness of lifestyle interventions, and thus, interventions may require consideration of the local context.

Prophylactic administration of metformin reduces gestational diabetes mellitus incidence in the high-risk populations: a meta-analysis : Metformin for gestational diabetes prevention

Metformin exerts a good efficacy for gestational diabetes mellitus (GDM) treatment by regulating gluconeogenesis and insulin resistance, while no consensus about its preventive effect on GDM is reached yet. Thus, this meta-analysis aimed to comprehensively investigate the prophylactic administration of metformin in pregnant women at high risk of GDM. Databases (EMBASE, PubMed, Cochrane, CNKI, Wanfang, CQVIP) were searched to screen papers concerning the GDM prevention using metformin in women at high risk of GDM (polycystic ovary syndrome (PCOS), obese, and pregestational insulin resistance patients) until January 2023. Our study showed that five cohort studies and fifteen randomized controlled trials (RCTs) involving 3911 women were included. Pooled analysis showed that prophylactic metformin treatment (vs. control treatment) greatly reduced GDM rate (relative risk (RR) = 0.59, 95% confidence intervals (CI): 0.43-0.80). Subgroup analyses also revealed that prophylactic metformin treatment (vs. control treatment) decreased the GDM rate in the following patients' types: (1) in Asians (RR = 0.31, 95% CI: 0.23-0.41), (2) in PCOS patients (RR = 0.42, 95% CI: 0.26-0.68), and (3) in patients receiving high dose of metformin (mean dose > 1000 mg) (RR = 0.59, 95% CI: 0.42-0.83). Concerning the quality of involved studies, the overall risk of bias was low. Egger's test implied that no publication bias existed in the findings. Moreover, sensitivity analysis suggested the pleasing robustness of the results. In conclusion, prophylactic metformin reduces GDM incidence in high-risk pregnant women, indicating its early-application benefits.

Major malformations risk following early pregnancy exposure to metformin: a systematic review and meta-analysis

Metformin is considered as first-line treatment for type 2 diabetes and an effective treatment for polycystic ovary syndrome (PCOS). However, evidence regarding its safety in pregnancy is limited. We conducted a systematic review and meta-analysis of major congenital malformations (MCMs) risk after first-trimester exposure to metformin in women with PCOS and pregestational diabetes mellitus (PGDM). Randomized controlled trials (RCTs) and observational cohort studies with a control group investigating risk of MCM after first-trimester pregnancy exposure to metformin were searched until December 2021. ORs and 95% CIs were calculated separately according to indications and study type using Mantel-Haenszel method; outcome data were combined using random-effects model. Eleven studies (two RCTs; nine observational cohorts) met the inclusion criteria: four included pregnant women with PCOS, four included those with PGDM and three evaluated both indications separately and were considered in both indication groups. In PCOS group, there were two RCTs (57 exposed, 52 control infants) and five observational studies (472 exposed, 1892 control infants); point estimates for MCM rates in RCTs and observational studies were OR 0.93 (95% CI 0.09 to 9.21) (I2=0%; Q test=0.31; p value=0.58) and OR 1.35 (95% CI 0.37 to 4.90) (I2=65%; Q test=9.43; p value=0.05), respectively. In PGDM group, all seven studies were observational (1122 exposed, 1851 control infants); the point estimate for MCM rates was OR 1.05 (95% CI 0.50 to 2.18) (I2=59%; Q test=16.34; p value=0.01). Metformin use in first-trimester pregnancy in women with PCOS or PGDM do not meaningfully increase the MCM risk overall. However, further studies are needed to characterize residual safety concerns.

Efficacy and safety of metformin in pregnant women with polycystic ovary syndrome: a systematic review with meta-analysis of randomized and non-randomized controlled trials

OBJECTIVE

To evaluate the efficacy and safety of using metformin in pregnant women with polycystic ovarian syndrome (PCOS) and to explore the most effective and safe protocol by using a meta-analysis method.

METHODS

Medline, EMBASE, Cochrane Library, and other databases were searched for randomized controlled trials and prospective cohort studies enrolling pregnant women with PCOS on receiving metformin or placebo or nothing. Subgroup analyses were undertaken.

RESULTS

A total of 17 studies involving 2899 patients were included. Compared with control group, the use of metformin significantly reduced the incidence of preterm delivery (cumulative rate 3.86% vs 9.19%, relative risk (RR), 0.42 [95% confidence interval (CI), 0.25-0.71,]; p = .001), early miscarriage (cumulative rate 6.58% vs 18.35%, RR, 0.40 [95% CI, 0.20-0.78]; p = .007), gestational diabetes (cumulative rate 12.86% vs 22.91%, RR, 0.48 [95% CI, 0.26-0.89]; p = .02), and pre-eclampsia (cumulative rate 4.95% vs 7.72%, RR, 0.61 [95% CI, 0.40-0.93]; p = .02), the need for insulin treatment throughout pregnancy (cumulative rate 2.14% vs 5.12%, RR, 0.43 [95% CI, 0.22-0.85]; p = .01), and weight gain of pregnant women (mean difference, -2.45, [95% CI, -3.04 to -1.85]; p < .00001).

CONCLUSIONS

The use of metformin in pregnant women with PCOS can significantly reduce maternal complications. No significant difference was observed in serious maternal adverse events. The efficacy and safety of metformin are worthy of recognition.

Different pregnancy outcomes according to the polycystic ovary syndrome diagnostic criteria: a systematic review and meta-analysis of 79 studies

OBJECTIVE

To correlate the distinct diagnostic criteria of polycystic ovary syndrome (PCOS) with the development of maternal and neonatal complications.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Pregnant women with PCOS.

INTERVENTION(S)

Maternal and neonatal complications were compared among women with PCOS diagnosed with different criteria.

MAIN OUTCOME MEASURE(S)

The primary outcomes of gestational diabetes mellitus and preeclampsia (PE) were assessed for every diagnostic criterion.

RESULT(S)

Seventy-nine studies were included. Regarding gestational diabetes, the overall pooled prevalence was 14% (95% confidence interval [CI], 11%-18%; I², 97%), reaching the highest level when polycystic ovarian morphology on ultrasound and 1 of the remaining 2 Rotterdam criteria (1/2 Rotterdam criteria) were used (18%; 95% CI, 13%-24%; I², 20%) and the lowest when polycystic morphology on ultrasound and hyperandrogenism were used (3%; 95% CI, 0%-19%; I², not applicable). Regarding PE, the overall pooled prevalence was 5% (95% CI, 4%-7%; I², 82%). The highest PE prevalence was reported when the National Institutes of Health criteria were used (14%; 95% CI, 5%-33%; I², 90%) and the lowest when menstrual irregularities and 1 of the 2 Rotterdam criteria were used (2%; 95% CI, 1%-3%; I², not applicable).

CONCLUSION(S)

The prevalence of gestational diabetes mellitus in pregnant women with PCOS does not differ according to the criteria used; however, women diagnosed with PCOS per the National Institutes of Health criteria are at higher risk of PE.

Exercise versus Metformin to Improve Pregnancy Outcomes among Overweight Pregnant Women: A Systematic Review and Network Meta-Analysis

Being overweight is associated with pregnancy-related disorders such as gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDP), and excessive maternal weight gain (MWG). Exercise and metformin reduce the risk of these disorders. This network meta-analysis (NMA) aims to compare the effect of metformin and different types of exercise (aerobic, resistance and combined) on the risk of GDM, HDP, and MWG among overweight/obese pregnant women. Medline, EMBASE, Web of Science and Cochrane Library were searched from inception to June 2021. Meta-analyses and NMAs were performed. Sixteen randomized controlled trials were included. In the NMA, aerobic exercise showed an effect on GDM (RR = 0.51, 95% CI = 0.26, 0.97), and metformin a reduction in MWG (MWG = -2.93 kg, 95% CI = -4.98, -0.87). No intervention showed any effect on the reduction of HDP. Our study suggests that aerobic exercise may have the greatest effect in reducing the risk of GDM, and perhaps, the MWG. Strategies should be developed to increase adherence to this type of intervention among overweight women without contraindications. Although metformin could reduce MWG, medicalization of pregnancy in healthy women is not justified with the present results. More research is needed on the effect of the intensity and frequency of exercise sessions and the length of interventions.

Cost-effectiveness analysis of polycystic ovary syndrome management and the risk of gestational diabetes in pregnant women: a decision-tree model

BACKGROUND

This study estimated the cost-effectiveness of metformin to reduce the risk of gestational diabetes mellitus (GDM) in pregnant women with polycystic ovary syndrome (PCOS) from the US health-care payer perspective.

METHODS

A decision tree was developed to simulate the progression of PCOS in a hypothetical cohort of 10,000 pregnant women diagnosed with PCOS and two scenarios were tested. Normal glucose regulation without developing GDM, average cost-effectiveness ratios (ACER), and the incremental cost-effectiveness ratios (ICERs) were the outcome measures assessed through pregnancy. Evidence from randomized clinical trials and other published literature were used to assess disease progression and its associated health-care costs. Sensitivity analyses that varied key model parameters were conducted.

RESULTS

Management of PCOS with metformin was associated with lowest ACER ($669.78 per normal glucose regulation without GDM) as compared to 'no intervention' strategy. Metformin use is the most cost-effective strategy to manage PCOS during pregnancy with average cost savings of $7,593,372.97 and an average effect gain of 2271 of normal glucose regulation without GDM among pregnant women with PCOS. Sensitivity analyses determined that the results are robust.

CONCLUSIONS

Management of PCOS during pregnancy may be a cost-effective strategy to reduce GDM risk and its associated complications.

Metformin in pregnancy to avert gestational diabetes in women at high risk: Meta-analysis of randomized controlled trials

Previous randomized and observational studies on the efficacy of metformin in pregnancy to reduce incident gestational diabetes mellitus (GDM) in women at high risk (obesity, polycystic ovary syndrome [PCOS], or pregestational insulin resistance) have been conflicting and several groups are planning further randomized controlled trials (RCTs) to answer this question conclusively. This work assesses the efficacy of metformin in pregnancy to avert one outcome-incident GDM in women at high risk. We included RCTs comparing metformin with usual care or placebo controls in terms of incident GDM and recruiting women at high risk during early pregnancy. Eleven eligible trials enrolled 2370 adult women whose intervention arm consisted of metformin started at conception or before 20 weeks of gestation. Risk of GDM was similar in intervention compared with controls (risk ratio [RR] 1.03; 95% confidence interval [CI], 0.85-1.24). The data were of sufficient quality meeting the criteria for consistency and directness. We conclude that metformin does not contribute to averting the GDM outcome in women at high risk when initiated in pregnancy. The evidence provided by this synthesis affirms that further broad clinical trials investigating this question are no longer needed.

Physical exercise and metformin in the prevention of pre-eclampsia: systematic review

Abstract Introduction: Pre-eclampsia is a disorder that may occur during pregnancy but is still unknown and / or multifactorial causes. Objective: To verify whether physical exercise and metformin may be helpful in preventing preeclampsia. Method: This is a systematic review of the literature in PubMed / MEDLINE, Web of Science, Scopus, LILACS and Cochrane. This review followed the critiques of the PRISMA checklist. Bias assessment was used for the Cochrane Handbook for Systematical Reviews of Interventions (Version 5.1.0) for clinical trials and the Downs and Black scale for cohort and case-control studies. Results: 17 studies were within the established criteria. The subjects evaluated were: pre-eclampsia, cardiovascular metabolic factors, physiotherapeutic therapies and the effects of physical exercise and metformin on the circulatory system. Conclusion: There is a need for adapted techniques and new protocols according to the contingencies and complications of pregnancy. During pregnancy, it is suggested a greater interdisciplinarity of knowledge among professionals and that the therapy receives adjustments against the metabolic alterations of the reproductive system. In order to prevent preeclampsia, the study suggests a program of individual exercises that include greater assistance, verification and / or comprehension of possible changes and their limits during pregnancy. As well as, the adjuvant use of metformin of 1000 mg/d in the initial phase, with the purpose of maintaining the effects of the drug due to renal clearance during pregnancy, until reaching a maximum of 1500 mg/d, to avoid side effects of the drug.

Metformin therapy before conception versus throughout the pregnancy and risk of gestational diabetes mellitus in women with polycystic ovary syndrome: a systemic review, meta-analysis and meta-regression

The results of studies that assessed the impact of metformin treatments on gestational diabetes mellitus (GDM) in patients with polycystic ovary syndrome (PCOS) are inconclusive. In addition, the impact of time and duration of metformin therapy for an optimum reduction of GDM has not been reported in these studies. This study aimed to summarize current knowledge regarding the effect of metformin-therapy before conception versus throughout pregnancy on the risk of GDM in women with PCOS. PubMed, Scopus, Google Scholar and ScienceDirect databases were searched to identify relevant studies. Both fixed and random effect models were used. Subgroup analyses were performed based on the on the study methodology. The association between the PCOS status and GDM was assessed using the univariate and multiple meta-regression analysis adjusted by the BMI and metformin therapy. Forty-eight of 1397 identified studies were included involving 5711 PCOS patients and 20,296 controls. Regardless of metformin therapy, the prevalence of GDM diagnosed in the second trimester among women with PCOS was significantly higher than healthy controls that was independent of obesity. Including all studies, the increased risk of GDM among women with PCOS, compared to healthy controls, disappeared after the adjustment of metformin-therapy (β = 0.08, 95% CI 0.04, 0.2; p = 0.624). By excluding observational studies as a source of bias, the prevalence of GDM among women with PCOS treated using metformin before conception till the end of pregnancy did not differ from treated just before conception (β = - 0.09, 95% CI - 0.2, 0.02; p = 0.092) or those without metformin therapy (β = - 0.05, 95% CI - 0.07, 0.04; p = 0.301). The results remained unchanged after the subgroup analysis based on the methodology of RCTs and non-RCTs studies. The main body of literature in the current meta-analysis was observational, which may be mixed with some sources of bias. Also, a lack of well-designed and high quality interventional studies means that the findings should be interpreted with cautious. In this respect, decisions regarding the continuation or discontinuation of metformin therapy in women with PCOS are somewhat arbitrary and can be made individually based on the patient's condition given the presence or absence of other GDM risk factors. Additional well-designed RCTs still need for precise recommendation.

Targeting the vascular dysfunction: Potential treatments for preeclampsia

Preeclampsia is a pregnancy-specific disorder, primarily characterized by new-onset hypertension in combination with a variety of other maternal or fetal signs. The pathophysiological mechanisms underlying the disease are still not entirely clear. Systemic maternal vascular dysfunction underlies the clinical features of preeclampsia. It is a result of oxidative stress and the actions of excessive anti-angiogenic factors, such as soluble fms-like tyrosine kinase, soluble endoglin, and activin A, released by a dysfunctional placenta. The vascular dysfunction then leads to impaired regulation and secretion of relaxation factors and an increase in sensitivity/production of constrictors. This results in a more constricted vasculature rather than the relaxed vasodilated state associated with normal pregnancy. Currently, the only effective "treatment" for preeclampsia is delivery of the placenta and therefore the baby. Often, this means a preterm delivery to save the life of the mother, with all the attendant risks and burdens associated with fetal prematurity. To lessen this burden, there is a pressing need for more effective treatments that target the maternal vascular dysfunction that underlies the hypertension. This review details the vascular effects of key drugs undergoing clinical assessment as potential treatments for women with preeclampsia.

Efficacy of metformin on pregnancy complications in women with polycystic ovary syndrome: a meta-analysis

OBJECTIVE

To evaluate the efficacy of metformin administration throughout pregnancy on pregnancy-related complications in women with polycystic ovary syndrome (PCOS).

STUDY DESIGN

MEDLINE and ScienceDirect were searched to retrieve relevant trials. The endpoint was the incidence of complications of pregnancy, gestational diabetes mellitus (GDM), pre-eclampsia (PE), miscarriage and premature birth included.

RESULTS

Five studies with 502 PCOS patients with metformin administration throughout pregnancy and 427 controls who used metformin just to get conception were included in our meta-analysis. In study group, a significantly lower change of emerging miscarriage and premature birth was observed, the pooled relative risk (RR) was 0.32 (95% confidence interval (CI): 0.19-0.56) for miscarriage and 0.40 (95%CI: 0.18-0.91) for premature birth. No significant difference was demonstrated in emerging GDM and PE.

CONCLUSIONS

Metformin therapy throughout pregnancy can reduce the RR of miscarriage and premature birth incidence in PCOS patients with no serious side effects.

Effect of metformin intervention during pregnancy on the gestational diabetes mellitus in women with polycystic ovary syndrome: a systematic review and meta-analysis

Metformin is an effective insulin sensitizer treating type 2 diabetes mellitus. However, the functional consequences of metformin administration throughout pregnancy on gestational diabetes mellitus (GDM) with polycystic ovary syndrome (PCOS) have not been assessed. We therefore performed a meta-analysis and system review to determine the effect of metformin on GDM in PCOS. A meta-analysis was performed on the published studies before December, 2013. Meta-analysis examined whether metformin could reduce GDM occurrence in PCOS with a fixed effect model. The odds ratio (OR) with 95% confidence interval (95% CI) was calculated to estimate the strength of association. A total of 13 studies including 5 RCTs and 8 non-RCTs were enrolled. Ultimately, effectiveness analysis demonstrated that, in total, there was no significant availability of metformin on GDM in PCOS in contrast to placebo (OR = 1.07, 95% CI 0.60-1.92) in RCTs and significant availability of metformin on GDM (OR = 0.19, 95% CI 0.13-0.27) was indicated in non-RCTs. In summary, according to the results of our meta-analysis, strictly, metformin did not significantly effect on GDM with PCOS, though more multicenters RCTs still need to be investigated.