Oral hypoglycemic agents vs insulin in management of gestational diabetes: a systematic review and metaanalysis

Diabetes in pregnancy

Diabetes in pregnancy is still considered a high-risk condition for both mother and baby. Even in the best centres, malformation and mortality rates are reportedly twofold to fivefold higher than in the background population, and pregnancy planning rates remain obstinately poor. Increasing global rates of type 2 diabetes are now extending into pregnancy, with similarly poor outcomes to type 1 diabetes, and excess maternal weight is adding to the complexity of management. Over the last 5-10 years, several randomised trials have offered new insight into the role of oral hypoglycaemic drugs and insulin analogues in pregnancy, while continuous subcutaneous insulin infusion (CSII) pumps and continuous glucose monitors (CGMs) are under scrutiny. The relevance of minor degrees of hyperglycaemia to adverse pregnancy outcome was clearly demonstrated by the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) study, but translation of these data into clinical practice has proved challenging because of the continuum of risk. Long-term metabolic and cardiovascular implications of hyperglycaemia during pregnancy for mother and child are now generally recognised with major implications for public health.

Use of antidiabetic agents in the treatment of gestational diabetes mellitus in Germany, 2008-2012

AIM

Adequate blood glucose control during pregnancy is important because gestational diabetes mellitus (GDM) is known to have adverse effects on the mother and child. Due to an increasing prevalence of GDM in recent years, more information on the use of different antidiabetic agents is required, which was the aim of the present study.

MATERIAL AND METHODS

Data from 32 diabetic practices in Germany were collected from January 2008 to December 2012 and analyzed using the Disease Analyzer Database. All women with International Classification of Diseases diagnosis O24 (that is, GDM) participated, except for patients with known type I or II diabetes mellitus, who were excluded. Analysis focused on the proportion of women requiring drug treatment in general. Thereafter, subanalysis was performed with a focus on the administration of different antidiabetic agents, namely insulin, metformin, and sulfonylurea.

RESULTS

Within the given timeframe, medication-based treatment for GDM significantly rose to reach 30.8% of all women with GDM. Both the administration of insulin and metformin grew considerably within the 5-year period with metformin being increasingly used without supplemental insulin and at lower dosages. Within the insulin treatment arm, insulin analogues became increasingly important. The proportion of sulfonylurea remained stable (0.2%).

CONCLUSIONS

GDM is more often treated with antidiabetic agents and, due to the fact that metformin is more frequently prescribed, it can be assumed that it is increasingly regarded as a safe and effective alternative to insulin.

Changing trends in management of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is on the rise globally. In view of the increasing prevalence of GDM and fetal and neonatal complications associated with it, there is a splurge of research in this field and management of GDM is undergoing a sea change. Trends are changing in prevention, screening, diagnosis, treatment and future follow up. There is emerging evidence regarding use of moderate exercise, probiotics and vitamin D in the prevention of GDM. Regarding treatment, newer insulin analogs like aspart, lispro and detemir are associated with better glycemic control than older insulins. Continuous glucose monitoring systems and continuous subcutaneous insulin systems may play a role in those who require higher doses of insulin for sugar control. Evidence exists that favors metformin as a safer alternative to insulin in view of good glycemic control and better perinatal outcomes. As the risk of developing GDM in subsequent pregnancies and also the risk of overt diabetes in later life is high, regular assessment of these women is required in future. Lifestyle interventions or metformin should be offered to women with a history of GDM who develop pre-diabetes. Further studies are required in the field of prevention of GDM for optimizing obstetric outcome.

Metformin in gestational diabetes: An emerging contender

Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance occurring first time during pregnancy. Its prevalence is simultaneously increasing with the global rise of diabesity. GDM commonly develops, when maternal glucose metabolism is unable to compensate for the progressive development of insulin resistance, arising primarily from the consistently rising diabetogenic placental hormones. It classically develops during the second or third trimester. Theoretically, insulin sensitizers should have been the ideal agent in its treatment, given the insulin resistance, the major culprit in its pathogenesis. Fortunately, majority of women can be treated satisfactorily with lifestyle modification, and approximately 20% requires more intensive treatment. For several decades, insulin has been the most reliable treatment strategy and the gold standard in GDM. Metformin is effective insulin sensitizing agent and an established first line drug in type 2 diabetes currently. As it crosses the placenta, a safety issue remains an obstacle and, therefore, metformin is currently not recommended in the treatment of GDM. Nevertheless, given the emerging clinically equivalent safety and efficacy data of metformin compared to insulin, it appears that it may perhaps open a rather new door in managing GDM. The aim of this review is to critically analyze, the safety and efficacy data of metformin regarding its use in GDM and pregnant mothers with polycystic ovarian disease, which has emerged in past decades.

Oral antidiabetic agents in gestational diabetes: a narrative review of current evidence

Gestational diabetes mellitus (GDM) classically occurs when maternal glucose metabolism is unable to compensate the progressive development of insulin resistance that arises from the continuously rising diabetogenic placental hormones. Although most women can be treated satisfactorily with diet alone, some require more intensive treatment. Insulin has been the most reliable treatment strategy in GDM over several decades. Although a long time has passed since the publication of two randomized controlled trials suggesting comparable efficacy and safety of metformin and glibenclamide, international bodies have not yet approved these oral agents. However, with the consistently emerging efficacy and safety data of these two drugs in the past decade, they may perhaps open a rather new door. The aim of this narrative review is to critically evaluate the existing evidence regarding safety and efficacy of oral drugs in GDM accumulated since the first publication in year 2000, suggesting clinical equivalency of glibenclamide (glyburide).

Use of oral anti-diabetic agents in pregnancy: a pragmatic approach

Insulin is the gold standard for treatment of hyperglycemia during pregnancy, when lifestyle measures do not maintain glycemic control during pregnancy. However, recent studies have suggested that certain oral hypoglycemic agents (metformin and glyburide) may be safe and be acceptable alternatives. There are no serious safety concerns with metformin, despite it crossing the placenta. Neonatal outcomes are also comparable, with benefit of reductions in neonatal hypoglycemia, maternal hypoglycemia and weight gain, and improved treatment satisfaction. Glibenclamide is more effective in lowering blood glucose in women with gestational diabetes, and with a lower treatment failure rate than metformin. Although generally well-tolerated, some studies have reported higher rates of pre-eclampsia, neonatal jaundice, longer stay in the neonatal care unit, macrosomia, and neonatal hypoglycaemia. There is also paucity of long-term follow-up data on children exposed to oral agents in utero. This review aims to provide an evidence-based approach, concordant with basic and clinical pharmacological knowledge, which will help medical practitioners use oral anti-diabetic agents in a rational and pragmatic manner. Pubmed search was made using Medical Subject Headings (MESH) terms “Diabetes” and “Pregnancy” and “Glyburide”; “Diabetes” and “Pregnancy” and “Metformin”. Limits were randomized controlled trials (RCTs) and meta-analysis. The expert reviews on the topic were also used for discussion. Additional information (studies/review) pertaining to discussion under sub-headings like safety during breastfeeding; placental transport; long-term safety data were searched (pubmed/cross-references/expert reviews).

Glibenclamide, metformin, and insulin for the treatment of gestational diabetes: a systematic review and meta-analysis

OBJECTIVE

To summarize short term outcomes in randomized controlled trials comparing glibenclamide or metformin versus insulin or versus each other in women with gestational diabetes requiring drug treatment.

DESIGN

Systematic review and meta-analysis.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized controlled trials that fulfilled all the following: (1) published as full text; (2) addressed women with gestational diabetes requiring drug treatment; (3) compared glibenclamide v insulin, metformin v insulin, or metformin v glibenclamide; and (4) provided information on maternal or fetal outcomes.

DATA SOURCES

Medline, CENTRAL, and Embase were searched up to 20 May 2014.

OUTCOMES MEASURES

We considered 14 primary outcomes (6 maternal, 8 fetal) and 16 secondary (5 maternal, 11 fetal) outcomes.

RESULTS

We analyzed 15 articles, including 2509 subjects. Significant differences for primary outcomes in glibenclamide v insulin were obtained in birth weight (mean difference 109 g (95% confidence interval 35.9 to 181)), macrosomia (risk ratio 2.62 (1.35 to 5.08)), and neonatal hypoglycaemia (risk ratio 2.04 (1.30 to 3.20)). In metformin v insulin, significance was reached for maternal weight gain (mean difference -1.14 kg (-2.22 to -0.06)), gestational age at delivery (mean difference -0.16 weeks (-0.30 to -0.02)), and preterm birth (risk ratio 1.50 (1.04 to 2.16)), with a trend for neonatal hypoglycaemia (risk ratio 0.78 (0.60 to 1.01)). In metformin v glibenclamide, significance was reached for maternal weight gain (mean difference -2.06 kg (-3.98 to -0.14)), birth weight (mean difference -209 g (-314 to -104)), macrosomia (risk ratio 0.33 (0.13 to 0.81)), and large for gestational age newborn (risk ratio 0.44 (0.21 to 0.92)). Four secondary outcomes were better for metformin in metformin v insulin, and one was worse for metformin in metformin v glibenclamide. Treatment failure was higher with metformin than with glibenclamide.

CONCLUSIONS

At short term, in women with gestational diabetes requiring drug treatment, glibenclamide is clearly inferior to both insulin and metformin, while metformin (plus insulin when required) performs slightly better than insulin. According to these results, glibenclamide should not be used for the treatment of women with gestational diabetes if insulin or metformin is available.Systematic review registration NCT01998113.

Oral antihyperglycemic treatment options for type 2 diabetes mellitus

Table 3 provides an overview of the oral antihyperglycemic drugs reviewed in this article. A 2011 meta-analysis by Bennett and colleagues found low or insufficient quality of evidence favoring an initial choice of metformin, SUs, glinides, TZDs, or (table see text) DPP-4 inhibitors (alpha-glucosidase inhibitors, bromocriptine mesylate, and SGLT2 inhibitors were not included in this meta-analysis) with regard to the outcomes measures of all-cause mortality, cardiovascular events and mortality, and incidence of microvascular disease (retinopathy, nephropathy, and neuropathy) in previously healthy individuals with newly diagnosed T2DM. Likewise, the Bennett and colleagues meta-analysis judged these drugs to be of roughly equal efficacy with regard to reduction of HbA1c (1%–1.6%) from the pretreatment baseline. The ADOPT clinical trial of 3 different and, at the time, popular, oral monotherapies for T2DM provides support for the consensus recommendation of metformin as first-line therapy. The ADOPT trial showed slightly superior HbA1c reduction for rosiglitazone compared with metformin, which was in turn superior to glyburide. However, significant adverse events, including edema, weight gain, and fractures, were more common in the rosiglitazone-treated patients. The implication of this trial is that the combination of low cost, low risk, minimal adverse effects, and efficacy of metformin justifies use of this agent as the cornerstone of oral drug treatment of T2DM. Judicious use of metformin in groups formerly thought to be at high risk for lactic acidosis (ie, those with CHF, chronic kidney disease [eGFR >30 mL/min/1.73 m2], and the elderly) may be associated with mortality benefit rather than increased risk. Secondary and tertiary add-on drug therapy should be individualized based on cost, personal preferences, and overall treatment goals, taking into account the wishes and priorities of the patient.

Effect comparison of metformin with insulin treatment for gestational diabetes: a meta-analysis based on RCTs

PURPOSE

To compare the effects of metformin with insulin on maternal and neonatal outcomes in gestational diabetes mellitus (GDM).

METHODS

A literature search in PUBMED, EMBASE, Science Direct, Springer link, and Cochrane library was conducted using the following search terms: "Gestational Diabetes" or "GDM", and "insulin" and "metformin". Quality assessment of included studies was determined with Quality Assessment of Diagnostic Accuracy Studies. Review Manger 5.2 was used to analyze mean difference (MD)/risk ratio (RR) and 95 % confidence interval (CI) in random-effects model or fixed-effects model depending on the level of heterogeneity.

RESULTS

A total of 11 studies were identified. There was no significant difference of the effect on maternal outcomes between the two treatments in glycohemoglobin A1c levels (P = 0.37), fasting blood glucose (P = 0.66), and the incidence of preeclampsia (P = 0.26); whereas, significantly reduced results were found in the metformin group in pregnancy-induced hypertension (PIH) rate (RR = 0.53, 95 % CI 0.31-0.90, P = 0.02), average weight gains after enrollment (MD = -1.28, 95 % CI -1.54 to -1.01, P < 0.0001), and average gestational ages at delivery (MD = 0.94, 95 % CI -0.21 to -0.01, P = 0.03). Regarding neonatal outcomes, when compared with insulin group, metformin presented significantly lower average birth weights (MD = -44.35, 95 % CI -85.79 to -2.90, P = 0.04), incidence of hypoglycemia (RR = 0.69, 95 % CI 0.55-0.87, P = 0.001) and neonatal intensive care unit (NICU) (RR = 0.82, 95 % CI 0.67-0.99, P = 0.04).

CONCLUSION

Metformin can significantly reduce several adverse maternal and neonatal outcomes including PIH rate, incidence of hypoglycemia and NICU, thus it may be an effective and safe alternative or additional treatment to insulin for GDM women.

The Role of Metformin in Metabolic Disturbances during Pregnancy: Polycystic Ovary Syndrome and Gestational Diabetes Mellitus

Maintenance of gestation implicates complex function of multiple endocrine mechanisms, and disruptions of the global metabolic environment prompt profound consequences on fetomaternal well-being during pregnancy and postpartum. Polycystic Ovary Syndrome (PCOS) and gestational diabetes mellitus (GDM) are very frequent conditions which increase risk for pregnancy complications, including early pregnancy loss, pregnancy-induced hypertensive disorders, and preterm labor, among many others. Insulin resistance (IR) plays a pivotal role in the pathogenesis of both PCOS and GDM, representing an important therapeutic target, with metformin being the most widely prescribed insulin-sensitizing antidiabetic drug. Although traditional views neglect use of oral antidiabetic agents during pregnancy, increasing evidence of safety during gestation has led to metformin now being recognized as a valuable tool in prevention of IR-related pregnancy complications and management of GDM. Metformin has been demonstrated to reduce rates of early pregnancy loss and onset of GDM in women with PCOS, and it appears to offer better metabolic control than insulin and other oral antidiabetic drugs during pregnancy. This review aims to summarize key aspects of current evidence concerning molecular and epidemiological knowledge on metformin use during pregnancy in the setting of PCOS and GDM.

Efficacy and safety of oral antidiabetic drugs in comparison to insulin in treating gestational diabetes mellitus: a meta-analysis

Objective

To assess the efficacy and safety of oral antidiabetic drugs (OADs) in gestational diabetes mellitus (GDM) in comparison to insulin.

Methods

A meta-analysis of randomized controlled trials was conducted. The efficacy and safety of OADs in comparison to insulin in GDM patients were explored. Studies were identified by conducting a literature search using the electronic databases of Medline, CENTRAL, CINAHL, LILACS, Scopus and Web of Science in addition to conducting hand search of relevant journals from inception until October 2013.

Results

Thirteen studies involving 2,151 patients met the inclusion criteria. These studies were randomized controlled trials of metformin and glyburide in comparison to insulin therapy. Our results indicated a significant increase in the risk for preterm births (RR, 1.51; 95% CI, 1.04–2.19, p = 0.03) with metformin compared to insulin. However, a significant decrease in the risk for gestational hypertension (RR, 0.54; 95% CI, 0.31–0.91, p = 0.02) was found. Postprandial glucose levels also decreased significantly in patients receiving metformin (MD, −2.47 mg/dL; 95% CI, −4.00, −0.94, p = 0.002). There was no significant difference between the two groups for the remaining outcomes. There were significant increases in the risks of macrosomia (RR, 2.34; 95% CI, 1.18–4.63, p = 0.03) and neonatal hypoglycemia (RR, 2.06; 95% CI, 1.27–3.34, p = 0.005) in the glyburide group compared to insulin whereas results for the other analyzed outcomes remained non-significant.

Conclusion

The available evidence suggests favorable effects of metformin in treating GDM patients. Metformin seems to be an efficacious alternative to insulin and a better choice than glyburide especially those with mild form of disease.

Recent advances in the diagnosis and management of gestational diabetes

Gestational diabetes is a condition which is seen in 7% of pregnancies and have potential risks for both mother and fetus. Despite its importance, there is not any golden standard approaches to the diagnosis and management of the disease. The aim of this review was to investigate the advances in the diagnosis and management of gestational diabetes in recent years.

Dichotomisation of a continuous outcome and effect on meta-analyses: illustration of the distributional approach using the outcome birthweight

BACKGROUND

Power and precision are greater in meta-analyses than individual study analyses. However, dichotomisation of continuous outcomes in certain studies poses a problem as estimates from primary studies can only be pooled if they have a common outcome. Meta-analyses may include pooled summaries of either or both the continuous and dichotomous forms, and potentially have a different combination of studies for each depending on whether the outcome was dichotomised in the primary studies or not. This dual-outcome issue can lead to loss of power and/or selection bias. In this study we aimed to illustrate how dichotomisation of a continuous outcome in primary studies may result in biased estimates of pooled risk and odds ratios in meta-analysis using secondary analyses of published meta-analyses with the outcome, birthweight, which is commonly analysed both as continuous, and dichotomous (low birthweight: birthweight < 2,500 g).

METHODS

Meta-analyses published in January 2010 - December 2011 were obtained using searches in PubMed, Embase, Web of Science, and Cochrane Database of Systematic Reviews with the outcome birthweight. We used a distributional method to estimate the pooled odds/risk ratio of low birthweight and its standard error as a function of the data reported in the primary studies of the included meta-analyses where accessible.

RESULTS

Seventy-six meta-analyses were identified. Thirty-seven percent (28/76) of the meta-analyses reported only the dichotomous form of the outcome while 26% (20/76) reported only the continuous form. In one meta-analysis (1/76), birthweight was analysed as continuous for one intervention and as binary for another and 36% (27/76) presented both dichotomous and continuous birthweight summaries. In meta-analyses with a continuous outcome, primary studies data were accessible in 39/48 and secondary analyses using the distributional approach provided consistent inferences for both the continuous and distributional estimates in 38/39.

CONCLUSION

The distributional method applied in primary studies allows both a continuous and dichotomous outcome to be estimated providing consistent inferences. The use of this method in primary studies may restrict selective outcome bias in meta-analyses.

Metformin vs insulin in the management of gestational diabetes: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of metformin compared with insulin in achieving glycemic control and investigate the maternal and neonatal outcomes in gestational diabetes mellitus.

METHODS

We searched four electronic databases from inception through December 2012. Terms for Gestational diabetes/gestational diabetes mellitus/diabetes pregnancy AND/OR Metformin/hypoglycemic drugs/Hypoglycemic Agents/Antidiabetic Medications were used in the search. Two investigators independently reviewed titles and abstracts, performed data abstraction on full articles, and assessed study quality. Meanwhile, manual search of other resources and the search on Google Scholar were also carried out to identify more related articles .Rev Man 5.0 was used to analyze the data.

RESULTS

Six randomized clinical trials involving 1420 subjects were included. The current limited data suggested that using metformin in gestational diabetes subjects did not significantly increase adverse maternal outcomes and neonatal outcomes, also with less weight gain and neonatal hypoglycemia, but a higher incidence of premature birth.

CONCLUSIONS

Metformin will not increase the incidence of adverse maternal outcomes and neonatal outcomes.

First-trimester exposure to metformin and risk of birth defects: a systematic review and meta-analysis

BACKGROUND

Metformin is generally considered a non-teratogenic drug; however, only a few studies specifically designed to assess the rate of congenital anomalies after metformin use have been published in the literature. The objects of the present study were to review all of the prospective and retrospective studies reporting on women treated with metformin at least during the first trimester of their pregnancy and to estimate the overall rate of major birth defects.

METHODS

Databases were searched for English language articles until December 2013. Inclusion criteria for the meta-analysis were: a case group of women with PCOS or pre-pregnancy type 2 diabetes and first-trimester exposure to metformin; a disease-matched control group which was not exposed to metformin or other oral anti-diabetic agents; and a list of the major anomalies in both the study and the control groups. A random effects model was used for the meta-analysis of data, using odds ratios. Studies not fulfilling the inclusion criteria for the meta-analysis but reporting relevant data on major malformations in women diagnosed with PCOS were then used to estimate the overall birth defects rate.

RESULTS

Meta-analysis of nine controlled studies with women affected by PCOS detected that the rate of major birth defects in the metformin-exposed group was not statistically increased compared with the disease-matched control group and that there was no significant heterogeneity among the studies. The metformin-exposed sample was composed of 351 pregnancies and the OR of major birth defects was 0.86 (95% confidence interval: 0.18-4.08; Pheterogeneity = 0.71). By evaluating all of the non-overlapping PCOS studies reported in the literature, even those without an appropriate control group, the overall rate of major anomalies was 0.6% in the sample of 517 women who discontinued the therapy upon conception or confirmation of pregnancy and 0.5% in the sample of 634 women who were treated with metformin throughout the first trimester of their pregnancy. Regarding type 2 diabetic women, we did not identify a sufficient number of studies with metformin exposure during the first trimester to proceed with the meta-analysis.

CONCLUSIONS

There is currently no evidence that metformin is associated with an increased risk of major birth defects in women affected by PCOS and treated during the first trimester. However larger ad hoc studies are warranted in order to definitely confirm the safety and efficacy of this drug in pregnancy.

The use of glyburide in the management of gestational diabetes mellitus: a meta-analysis

PURPOSE

Glyburide has been used for managing gestational diabetes mellitus (GDM) in a number of countries. It is rather inexpensive. However, its efficacy and safety remain controversial. With this meta-analysis, we evaluated glyburide in comparison with insulin.

MATERIAL/METHODS

With a systematic literature search strategy, a total of 93 randomized controlled trials (RCTs) with insulin and glyburide comparison were identified. Based on the revised Consolidated Standards of Reporting Trials (CONSORT) checklist, five of them met the inclusion criteria and were included in this meta-analysis.

RESULTS

Six hundred and seventy four subjects were included in these five RCTs. When compared with insulin, glyburide had an increased relative risk (RR) for neonatal hypoglycemia (RR: 1.98; 95% confidence interval [CI]: 1.17, 3.36). Estimation of standard mean differences (SMD) showed that both fetal birth weight and incidence of macrosomia were higher in subjects receiving glyburide than in those receiving insulin (SMD: 0.21; 95% CI: 0.06, 0.36; RR: 2.22; 95% CI: 1.07, 4.61 respectively). There were no significant differences in maternal glucose control, glycated hemoglobin, the rate of Cesarean section, large-for-gestational age, neonatal hypocalcemia, length of stay for neonatal ICU admissions, preterm birth, or congenital anomalies.

CONCLUSIONS

Our study suggested that in women with GDM, glyburide is as effective as insulin, but the risks of neonatal hypoglycemia, high fetal birth weight, and macrosomia were higher.

Diabetes and the female reproductive system

The insulin/insulin-like growth factor (IGF) pathways and glucose metabolism act as mediators of human ovarian function and female fertility. In normal insulin action, insulin binds to its own receptors in the ovary to mediate steroidogenesis and act as a co-gonadotropin. Insulin with other factors may influence ovarian growth and cyst formation. The IGF pathway also seems to influence normal ovarian function. Insulin signaling affects reproductive function. Dysregulation of this pathway leads to altered puberty, ovulation, and fertility. Better understanding of the normal physiology and pathophysiology of insulin, IGF, and glucose effects on the human reproductive system will allow for better outcomes.

Efficacy and safety of metformin during pregnancy in women with gestational diabetes mellitus or polycystic ovary syndrome: a systematic review

BACKGROUND

Metformin is an effective oral anti-hyperglycemic agent that is widely used to manage diabetes mellitus type 2 in the general population and more recently, in pregnancy. However, as metformin crosses the placenta, its use during pregnancy raises concerns regarding potential adverse effects on the mother and fetus.

OBJECTIVE

(i) To provide background for the use of metformin during pregnancy through a narrative review and (ii) to critically appraise the published evidence on the efficacy and safety of using metformin during pregnancy through a systematic review.

RESULTS

Metformin appears to be effective and safe for the treatment of gestational diabetes mellitus (GDM), particularly for overweight or obese women. However, patients with multiple risk factors for insulin resistance may not meet their treatment goals with metformin alone and may require supplementary insulin. Evidence suggests that there are potential advantages for the use of metformin over insulin in GDM with respect to maternal weight gain and neonatal outcomes. Furthermore, patients are more accepting of metformin than insulin. The use of metformin throughout pregnancy in women with polycystic ovary syndrome reduces the rates of early pregnancy loss and preterm labor and protects against fetal growth restriction. There have been no demonstrable teratogenic effects, intra-uterine deaths or developmental delays with the use of metformin.

CONCLUSIONS

The publications reviewed in this paper support the efficacy and safety of metformin during pregnancy with respect to immediate pregnancy outcomes. Because there are no guidelines for the continuous use of metformin in pregnancy, the duration of treatment is based on clinical judgment and experience on a case-by-case basis.

Diabetes and pregnancy: an endocrine society clinical practice guideline

OBJECTIVE

Our objective was to formulate a clinical practice guideline for the management of the pregnant woman with diabetes.

PARTICIPANTS

The Task Force was composed of a chair, selected by the Clinical Guidelines Subcommittee of The Endocrine Society, 5 additional experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and innumerable e-mail communications enabled consensus for all recommendations save one with a majority decision being employed for this single exception.

CONCLUSIONS

Using an evidence-based approach, this Diabetes and Pregnancy Clinical Practice Guideline addresses important clinical issues in the contemporary management of women with type 1 or type 2 diabetes preconceptionally, during pregnancy, and in the postpartum setting and in the diagnosis and management of women with gestational diabetes during and after pregnancy.

Randomized trial of metformin vs insulin in the management of gestational diabetes

OBJECTIVE

To evaluate glycemic control in women receiving metformin or insulin for gestational diabetes, and to identify factors predicting the need for supplemental insulin in women initially treated with metformin.

STUDY DESIGN

Women with gestational diabetes who failed to achieve glycemic control with diet and exercise were randomized to receive metformin (n = 47) or insulin (n = 47). Criteria for inclusion were singleton pregnancy, diet, and exercise for a minimum period of 1 week without satisfactory glycemic control, absence of risk factors for lactic acidosis, and absence of anatomic and/or chromosome anomalies of the conceptus. Patients who were lost to prenatal follow-up were excluded.

RESULTS

Comparison of mean pretreatment glucose levels showed no significant difference between groups (P = .790). After introduction of the drug, lower mean glucose levels were observed in the metformin group (P = .020), mainly because of lower levels after dinner (P = .042). Women using metformin presented less weight gain (P = .002) and a lower frequency of neonatal hypoglycemia (P = .032). Twelve women in the metformin group (26.08%) required supplemental insulin for glycemic control. Early gestational age at diagnosis (odds ratio, 0.71; 95% confidence interval, 0.52-0.97; P = .032) and mean pretreatment glucose level (odds ratio, 1.061; 95% confidence interval, 1.001-1.124; P = .046) were identified as predictors of the need for insulin.

CONCLUSION

Metformin was found to provide adequate glycemic control with lower mean glucose levels throughout the day, less weight gain and a lower frequency of neonatal hypoglycemia. Logistic regression analysis showed that gestational age at diagnosis and mean pretreatment glucose level were predictors of the need for supplemental insulin therapy in women initially treated with metformin.

Metformin vs insulin in the management of gestational diabetes: a meta-analysis

BACKGROUND

Nowadays, there have been increasing studies comparing metformin with insulin. But the use of metformin in pregnant women is still controversial, therefore, we aim to examine the efficiency and safety of metformin by conducting a meta-analysis of randomized controlled trials (RCTs) comparing the effects of metformin with insulin on glycemic control, maternal and neonatal outcomes in gestational diabetes mellitus (GDM).

METHODS

We used the key words "gestational diabetes" in combination with "metformin" and searched the databases including Pubmed, the Cochrane Library, Web of knowledge, and Clinical Trial Registries. A random-effects model was used to compute the summary risk estimates.

RESULTS

Meta-analysis of 5 RCTs involving 1270 participants detected that average weight gains after enrollment were much lower in the metformin group (n = 1006, P = 0.003, SMD = -0.47, 95%CI [-0.77 to -0.16]); average gestational ages at delivery were significantly lower in the metformin group (n = 1270, P = 0.02, SMD = -0.14, 95%CI [-0.25 to -0.03]); incidence of preterm birth was significantly more in metformin group (n = 1110, P = 0.01, OR = 1.74, 95%CI [1.13 to 2.68]); the incidence of pregnancy induced hypertension was significantly less in the metformin group (n = 1110, P = 0.02, OR = 0.52, 95%CI [0.30 to 0.90]). The fasting blood sugar levels of OGTT were significantly lower in the metformin only group than in the supplemental insulin group (n = 478, P = 0.0006, SMD = -0.83, 95%CI [-1.31 to -0.36]).

CONCLUSIONS

Metformin is comparable with insulin in glycemic control and neonatal outcomes. It might be more suitable for women with mild GDM. This meta-analysis also provides some significant benefits and risks of the use of metformin in GDM and help to inform further development of management guidelines.

Perinatal outcome of infants born to diabetic mothers in a developing country--comparison of insulin and oral hypoglycemic agents

OBJECTIVE

To study the perinatal outcomes of infants born to mothers with gestational diabetes treated with insulin or oral hypoglycemic agents in a developing country.

DESIGN

Prospective observational cohort study.

SETTING

Tertiary-care perinatal center in southern India.

PARTICIPANTS

Babies born to mothers with gestational diabetes.

METHODS

Maternal details were obtained and physical examination was performed on the neonates. Babies were given hourly feeds soon after birth and blood glucoses checked at 1, 3, 5, 9 and 12 hours of life; hematocrit and calcium levels were also measured. Perinatal outcomes were compared between mothers who required insulin or an oral hypoglycemic agent for treatment of diabetes.

RESULTS

Of the 10,394 mothers who delivered during the study period, 574 (5.5%) were diagnosed to have gestational diabetes. 137 were treated with insulin and 141 with oral hypoglycemic agents. 44 (15.8%) babies were born preterm, 97 (35%) were large for gestational age, 13 (4.7%) were small for gestational age and 9 (3.2%) were macrosomic. Hypoglycemia was seen in 26 (9.3%) babies, congenital anomalies in 15 (5.4%) and birth injuries in 7 (2.5%). There was no difference between the two groups in any of the outcomes except for hyperbilirubinemia, which was more in the insulin group (13.7% vs 6.5%, P=0.04).

CONCLUSIONS

There was no difference in the perinatal outcome whether the mother received insulin or an oral hypoglycemic agent for treatment of gestational diabetes other than the increased incidence of hyperbilirubinemia in the insulin group.

Introduction of metformin for gestational diabetes mellitus in clinical practice: Has it had an impact?

OBJECTIVE

The aim of the study was to compare maternal and neonatal outcomes in women with gestational diabetes mellitus (GDM) treated with metformin in addition to the dietary and lifestyle advice versus those treated traditionally with dietary and lifestyle advice only.

STUDY DESIGN

A retrospective study of singleton pregnancies in women with GDM delivered between January 2008 to June 2010 (n=592) at the Jessop Wing, Royal Hallamshre Hospital, UK. Introduction of metformin in August 2008 led to two comparable groups, those women receiving metformin, lifestyle advice (including dietary advice) ± supplementary insulin and those women receiving lifestyle advice (including dietary advice) ± supplementary insulin. Two hundred and ninety three women were treated with metformin and lifestyle advice and remaining 299 with lifestyle advice only. Supplementary insulin was used in both the groups if needed. Outcomes were analyzed using the chi-squared and t-tests.

RESULTS

There were no significant differences in baseline maternal characteristics between the two groups. Metformin was tolerated throughout the pregnancy by 90% of the women in the metformin+lifestyle advice group. Supplementary insulin was required by 21% in the metformin+lifestyle advice group compared to 37% in the lifestyle advice group (OR 0.46; 95% CI 0.32-0.66). Women in the metformin group had a significantly lower incidence of macrosomia (birth weight>4kg) (8.2% vs. 14.3% (OR 0.56; 95% CI 0.33-0.99)), as well as birth weight >90th centile (14.8% vs. 23.7% (OR 0.56; 95% CI 0.37-0.85)). There were no significant differences in maternal outcome measures between the groups. No serious maternal or neonatal adverse events were observed with the use of metformin.

CONCLUSION

Metformin is safe and effective in the treatment of GDM in our experience. It is well tolerated and reduces the requirement for supplementary insulin. Women treated with metformin had a significantly lower incidence of macrosomic and large for gestational age neonates as well as a reduced caesarean section rate.

Contemporary management of gestational diabetes

PURPOSE OF REVIEW

To understand all of the current options available to treat glucose intolerance in pregnancy.

RECENT FINDINGS

Recent attention to the use of oral agents in the treatment of gestational diabetes remains controversial. This review will outline the advantages and disadvantages, as well as safety profiles of two classes of oral mediations.

SUMMARY

There are many effective treatments for gestational diabetes. Oral medications appear to be well tolerated and effective for treatment of gestational diabetes, and may offer a greater patient compliance. The literature supports use of oral medications as first-line treatment for patients with gestational diabetes that cannot achieve glycemic goals with diet and exercise.

The maternal womb: a novel target for cancer prevention in the era of the obesity pandemic?

The dramatic rise in worldwide prevalence of obesity has necessitated the search for more efficacious antiobesity strategies to counter the increased cancer risks in overweight and obese individuals. The mechanistic pathways linking obesity status with adult chronic diseases such as cancer remain incompletely understood. A growing body of evidence suggests that novel approaches and interventional agents to disrupt the feed-forward cycle of maternal to offspring obesity transfer that is initiated in utero will be important for stemming both the obesity pandemic and the associated increase in cancer incidence. The convergence of multiple research areas including those encompassing the insulin and insulin-like growth factor systems, epigenetics, and stem cell biology is providing insights into the potential for cancer prevention in adult offspring previously exposed to the intrauterine environment of overweight/obese mothers. Here, we review the current state of this nascent research field, with a focus on three major cancers, namely breast, colorectal, and liver, and suggest some possible future directions to optimize its impact for the health of future generations.

Gestational diabetes mellitus: Non-insulin management

Gestational diabetes mellitus (GDM) complicates a substantial number of pregnancies. There is consensus that in patients of GDM, excellent blood glucose control, with diet and, when necessary, oral hypoglycemics and insulin results in improved perinatal outcomes, and appreciably reduces the probability of serious neonatal morbidity compared with routine prenatal care. Goals of metabolic management of a pregnancy complicated with GDM have to balance the needs of a healthy pregnancy with the requirements to control glucose level. Medical nutrition therapy is the cornerstone of therapy for women with GDM. Surveillance with daily self-monitoring of blood glucose has been found to help guide management in a much better way than blood glucose checking in labs and clinics, which tends to be less frequent. Historically, insulin has been the therapeutic agent of choice for controlling hyperglycemia in pregnant women. However, difficulty in medication administration with multiple daily injections, potential for hypoglycemia, and increase in appetite and weight make this therapeutic option cumbersome for many pregnant patients. Use of oral hypogycemic agents (OHAs) in pregnancy has opened new vistas for GDM management. At present, there is a growing acceptance of glyburide (glibenclamide) use as the primary therapy for GDM. Glyburide and metformin have been found to be safe, effective and economical for the treatment of gestational diabetes. Insulin, however, still has an important role to play in GDM. GDM is a window of opportunity, which needs to be seized, for prevention of diabetes in future life. Goal of our educational programs should be not only to improve pregnancy outcomes but also to promote healthy lifestyle changes for the mother that will last long after delivery. Team effort on part of obstetricians and endocrinologists is required to make "the diabetes capital of the world" into "the diabetes care capital of the world".

Gestational diabetes mellitus: results from a survey of country prevalence and practices

OBJECTIVE

The association between gestational diabetes mellitus (GDM), perinatal complications and long-term morbidity is gaining increased attention. However, the global burden of GDM and the existing responses are not fully understood. We aimed to assess country prevalence and to summarize practices related to GDM screening and management.

METHODS

Data on prevalence and country practices were obtained from a survey administered to diabetologists, obstetricians and others working on GDM in 173 countries.

RESULTS

GDM prevalence estimates range from <1% to 28%, with data derived from expert estimates, and single-site, multi-site and national prevalence assessments. Seventy-four percent of countries that completed the survey have national GDM guidelines or recommendations. Countries use a variety of screening approaches. In the countries where universal screening is recommended, the percentage of pregnant women screened ranges from 10% to >90%.

CONCLUSIONS

We found large variations in estimated GDM prevalence, but direct comparison between countries is difficult due to different diagnostic strategies and subpopulations. Many countries do not perform systematic screening for GDM, and practices often diverge from guidelines. Countries need to carefully assess the cost and health impact of scaling up GDM screening and management in order to identify the best policy option for their population.