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

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.

Gestational diabetes mellitus and development of intergenerational non-alcoholic fatty liver disease (NAFLD) after delivery: a systematic review and meta-analysis

Background

It is known that gestational diabetes mellitus (GDM)-complicated pregnancies could affect maternal cardiometabolic health after delivery, resulting in hepatic dysfunction and a heightened risk of developing non-alcoholic fatty liver disease (NAFLD). Hence, this study aims to summarise existing literature on the impact of GDM on NAFLD in mothers and investigate the intergenerational impact on NAFLD in offspring.

Methods

Using 4 databases (PubMed, Embase, Web of Science and Scopus) between January 1980 and December 2023, randomized controlled trials and observational studies that assessed the effect of maternal GDM on intergenerational liver outcomes were extracted and analysed using random-effects meta-analysis to investigate the effect of GDM on NAFLD in mothers and offspring. Pooled odds ratio (OR) was calculated using hazards ratio (HR), relative risk (RR), or OR reported from each study, with corresponding 95% confidence intervals (CI), and statistical heterogeneity was assessed with the Cochran Q-test and I2 statistic, with two-sided p values. The study protocol was pre-registered on PROSPERO (CRD42023392428).

Findings

Twenty studies pertaining to mothers and offspring met the inclusion criteria and 12 papers were included further for meta-analysis on intergenerational NAFLD development. Compared with mothers without a history of GDM, mothers with a history of GDM had a 50% increased risk of developing NAFLD (OR 1.50; 95% CI: 1.21-1.87, over a follow-up period of 16 months-25 years. Similarly, compared with offspring born to non-GDM-complicated pregnancies, offspring born to GDM-complicated pregnancies displayed an approximately two-fold elevated risk of NAFLD development (2.14; 1.57-2.92), over a follow-up period of 1-17.8 years.

Interpretation

This systematic review and meta-analysis suggests that both mothers and offspring from GDM-complicated pregnancies exhibit a greater risk to develop NAFLD. These findings underline the importance of early monitoring of liver function and prompt intervention of NAFLD in both generations from GDM-complicated pregnancies.

Funding

No funding was available for this research.

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.

Effect of Galactooligosaccharide on PPARs/PI3K/Akt Pathway and Gut Microbiota in High-Fat and High-Sugar Diet Combined with STZ-Induced GDM Rat Model

Gestational diabetes mellitus (GDM) is a metabolic disorder, characterized by underlying glucose intolerance, diabetes onset or first diagnosis during pregnancy. Galactooligosaccharide (GOS) is essential for consumer protection as food supplementation. However, there is limited understanding of the effects of GOS on GDM. We successfully established a GDM rat model to explore GOS whether participated in PPARs/PI3K/Akt pathway and gut microbiota metabolites to treat for GDM. In this study, compared with the GDM group, GOS administration lowered the levels of TG, LDL-C, and HDL-C in rat serum, as well as improved the pathological changes pancreatic, liver, and kidney tissues. Compared with the GDM group, the protein expressions of PPARα, PPARγ, and PPARβ/δ markedly enhanced in GOS-treated groups (P < 0.01). Moreover, GOS administration upregulated the protein expressions of PPARα, PPARβ, PPARγ, PI3K, Akt, GLUT4, Bax, and Bcl2. GOS administration altered gut microbiota metabolites, including both SCFAs and BAs. Correlation analysis revealed close relationships between gut microbiota and experimental indicators. This study indicated that GOS effectively improved GDM in rats through the modulation of PPARs/PI3K/Akt pathway and gut microbiota. Thus, the GOS could be recommended as a candidate for novel therapy 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.

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.

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.

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.

One hundred years since insulin discovery: An update on current and future perspectives for pharmacotherapy of diabetes mellitus

Diabetes mellitus was considered a fatal malady until the discovery, extraction and commercial availability of insulins. Numerous other classes of drugs ranging from sulfonylureas to sodium-glucose co-transporter-2 inhibitors were then marketed. However, with the prevalence of diabetes mellitus increasing every year, many more drugs and therapies are under investigation. This review article aimed to summarize the significant developments in the pharmacotherapy of diabetes mellitus and outline the progress made by the recent advances, 100 years since insulins were first extracted successfully. Insulin analogues and insulin delivery pumps have further improved glycaemic control in diabetes mellitus. Cardiovascular and renal outcome trials have changed the landscape of diabetology, with some of these drugs also efficacious in nondiabetics. Newer drug delivery systems are being evaluated to improve the efficacy and reduce the dosing frequency and adverse effects of antidiabetics. Some newer drugs with novel mechanisms of action targeting type 1 and type 2 diabetes have also shown promise in recent clinical trials. These drugs include dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1-agonists, glucokinase activators, anti-CD3 monoclonal antibodies and glimins. Their efficacy needs to be evaluated in larger studies.

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.

Comparison of Insulin, Metformin, and Glyburide on Perinatal Complications of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

AIM

This systematic and meta-analysis was conducted to evaluate the efficacy and safety of insulin, metformin, and glyburide on perinatal complications for gestational diabetes mellitus (GDM).

METHODS

Medline (PubMed), EMBASE, The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials [CENTRAL], and Cochrane Methodology Register), Web of Science (Science and Social Science Citation Index), and ClinicalTrials (Clinicaltrials.gov) were searched, as well as manual searching. We included randomized controlled trials comparing efficacy and safety of metformin versus glyburide, metformin versus insulin, and glyburide versus insulin in patients with GDM.

RESULTS

We included 32 articles including 5,964 patients published from inception to July 2020. Compared with insulin, metformin was more effective at lower incidence of macrosomia (RR: 0.66, 95% CI: 0.50-0.88, p = 0.005), lower incidence of neonatal intensive care unit admission (RR: 0.78, 95% CI: 0.67-0.91, p = 0.002), less neonatal hypoglycemia (RR: 0.67, 95% CI: 0.56-0.80, p < 0.0001), decreased birth weight (BW) (SMD: -0.37, 95% CI: -0.62 to -0.12, p = 0.004), lower incidence of large for gestational age (RR: 0.76, 95% CI: 0.50-0.90, p = 0.002), shorter gestation age at delivery (MD: -0.22, 95% CI: -0.34 to -0.10, p = 0.0002), lower maternal weight gain (MD: -1.41, 95% CI: -2.28 to -0.55, p = 0.001), less incidence of caesarean section delivery (RR: 0.86, 95% CI: 0.78-0.95, p = 0.0004), lower maternal postprandial blood glucose (SMD: -0.41, 95% CI: -0.72 to -0.11, p = 0.008), and lower incidence of pregnancy-induced hypertension (RR: 0.47, 95% CI: 0.27-0.83, p = 0.01). However, glyburide, compared with insulin, was associated with higher BW (MD: 54.95, 95% CI: 3.87-106.03, p = 0.03) and increased the incidence of neonatal hypoglycemia (RR: 1.52, 95% CI: 1.12-2.07, p = 0.007). Meanwhile, compared to glyburide, metformin was associated with higher maternal fasting blood glucose (SMD: 0.20, 95% CI: 0.05-0.36, p = 0.01) and lower incidence of induction of labor (RR: 0.76, 95% CI: 0.59-0.97, p = 0.03).

CONCLUSIONS

This review suggests that metformin can decrease the incidence of perinatal complications, and it should be considered as a generally safe alternative to insulin.

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.

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.

Impact of treatment with metformin in comparison with insulin in gestational diabetes in libyan population a randomized controlled study

Background:

The aim of this study was the comparison of the glycemic control and maternal outcomes in women affected with gestational diabetes mellitus (GDM) managed with metformin versus insulin.

Materials and Methods:

The participants included in this study were 140 women diagnosed with GDM. They were randomized into two groups, women included in the first group were treated with metformin and the women of the second group were managed with insulin.

Results:

The glycemic control was similar in both the treatment arms and the only noteworthy difference was found in the mean fasting blood glucose, which was significantly higher in the women receiving insulin as compared to the women receiving metformin. There were no substantial differences in the maternal outcome with the use of metformin compared to insulin in women with GDM.

Conclusion:

The incidence of operative delivery was higher in metformin-treated group, whereas the hospital admission rate was considerably elevated in insulin-treated group.

Progress of Clinical Trials for the Treatment of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common and severe complications of pregnancy, which is not only associated with perinatal complications but also has a long-term adverse effect on maternal and their offsprings. At present, the treatment of GDM focuses on the control of maternal blood glucose. Although lifestyle changes, hypoglycemic drugs, blood glucose monitoring, and other medicines that can improve maternal blood glucose to a certain extent, there are still some patients affected and have adverse pregnancy outcomes. The prevention of GDM and the treatment of improving pregnancy outcomes are urgently needed. This review summarized recently published clinical trials related with the treatment of GDM, aiming to provide additional options for the treatment of GDM.

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.

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.

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.