Metformin versus insulin for gestational diabetes mellitus: a meta-analysis

Efficacy and safety of metformin during pregnancy: an update

During the last decades, gestational diabetes mellitus (GDM) prevalence has been on the rise. While insulin remains the gold standard treatment for GDM, metformin use during pregnancy is controversial. This review aimed to comprehensively assess the available data on the efficacy and safety of metformin during pregnancy, both for the mother and the offspring. Metformin has been validated for maternal efficacy and safety, achieving comparable glycemic control with insulin. Additionally, it reduces maternal weight gain and possibly the occurrence of hypertensive disorders. During the early neonatal period, metformin administration does not increase the risk of congenital anomalies or other major adverse effects, including lower APGAR score at 5 min, neonatal intensive care unit admissions, and respiratory distress syndrome. Several studies have demonstrated a reduction in neonatal hypoglycemia. Metformin has been associated with an increase in preterm births and lower birth weight, although this effect is controversial and depends on the indication for which it was administered. Evidence indicates possible altered fetal programming and predisposition to childhood obesity and metabolic syndrome during adulthood after use of metformin in pregnancy. With critical questions still requiring a final verdict, ongoing research on the field must be conducted.

Comparison of Neurodevelopmental Status in Early Infancy of Infants of Women With and Without Gestational Diabetes Mellitus

OBJECTIVES

To study the neurodevelopmental status of offsprings of mothers with gestational diabetes (OGDM) aged 3½ mo.

METHODS

This cross-sectional study was conducted at a tertiary hospital, New Delhi which included infants aged 3½ mo (+1 wk) who were either offsprings of women with gestational diabetes (cases) or infants of mothers without gestational diabetes mellitus presenting to tertiary care public hospital in India from January, 2018 through March, 2019, with enrollment of infants done between 10 April, 2018 and 30 March, 2019.

RESULTS

The development quotient (DQ) using Developmental Assessment Scales for Indian Infants (DASII) was calculated as Motor DQ, Mental DQ and a composite DQ. The mean motor DQ of the enrolled infants was 101.7 (12.02); it was significantly lower for OGDM than controls [101 (1.41) vs. 109.5 (10.6); P <0.001]. The mean mental DQ of the enrolled infants was 88.9 (12.0); it was significantly lower for OGDM than the control group [84 (9.89 vs. 88 (8.48); P = 0.03]. The total development quotient for the enrolled infants was 95.3 (11.3). The total development quotient for study group was significantly lower than the control group [92.5 (5.65) vs. 98.75 (9.54); P = 0.001].

CONCLUSIONS

The mean motor, mental total DQ of offsprings of mothers with GDM were significantly lower than those born to mothers without GDM. Hence follow up, early intervention should be considered for this high risk group.

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.

Immune–Metabolic Interactions and T Cell Tolerance in Pregnancy

Pregnancy depends on a state of maternal immune tolerance mediated by CD4+ regulatory T (Treg) cells. Uterine Treg cells release anti-inflammatory factors, inhibit effector immunity, and support adaptation of the uterine vasculature to facilitate placental development. Insufficient Treg cells or inadequate functional competence is implicated in infertility and recurrent miscarriage, as well as pregnancy complications preeclampsia, fetal growth restriction, and preterm birth, which stem from placental insufficiency. In this review we address an emerging area of interest in pregnancy immunology–the significance of metabolic status in regulating the Treg cell expansion required for maternal–fetal tolerance. We describe how hyperglycemia and insulin resistance affect T cell responses to suppress generation of Treg cells, summarize data that implicate a role for altered glucose metabolism in impaired maternal–fetal tolerance, and explore the prospect of targeting dysregulated metabolism to rebalance the adaptive immune response in women experiencing reproductive disorders.

Effectiveness of antidiabetic agents for treatment of gestational diabetes: A methodological quality assessment of meta-analyses and network meta-analysis

AIMS/INTRODUCTION

Despite there being several meta-analyses on the effects of antidiabetic agents in patients with gestational diabetes mellitus, the reliability of their findings is a concern, mainly due to undetermined methodological quality of these studies. This study aimed to assess the methodological quality of available meta-analyses and provide a summary estimation of the effectiveness of treatments modalities.

MATERIALS AND METHODS

PubMed, Web of Science and Scopus databases were comprehensively searched for retrieving relevant meta-analyses published in English up to May 2020. A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) was applied to evaluate methodological quality of eligible meta-analyses. A network meta-analysis was used to calculate the pooled odds ratio of maternal and neonatal outcomes in gestational diabetes mellitus patients treated with metformin or glyburide compared with those treated with insulin. The rank network analysis was carried out for ranking of the treatments and reporting the most efficient treatment.

RESULTS

A total of 27 and 17 studies were included for qualitative and quantitative syntheses, respectively; of these, just four studies were classified as high quality. The results showed that metformin had the highest probability of being the best treatment, compared with insulin and glyburide, for the majority of adverse neonatal outcomes, whereas glyburide was the best treatment in reducing the risk of adverse maternal outcomes. The results were not significantly changed after excluding low-quality studies.

CONCLUSIONS

This review study of available literature shows that metformin can be a superior option in most neonatal and maternal adverse pregnancy outcomes in women with gestational diabetes mellitus; the results need to be further updated by including future more qualified studies.

Metformin in Pregnancy for Women with Type 2 Diabetes: a Review

PURPOSE OF REVIEW

To review the current evidence for the use of metformin in pregnancy for women with type 2 diabetes.

RECENT FINDINGS

A large, multicenter, double-blind randomized controlled trial found that women with type 2 diabetes in pregnancy treated with metformin as an adjunct to insulin therapy had less gestational weight gain, insulin requirements, caesarian sections, macrosomia, and neonatal adiposity, but more neonates were small for gestational age (SGA) compared with insulin alone. It is unclear if the higher number of SGA infants are a direct result of metformin exposure or mediated through other effects such as less gestational weight gain and improved glycemic control. Additional follow-up studies of offspring exposed to metformin in utero are required. Metformin may be a useful adjunctive treatment for women with type 2 diabetes in pregnancy to help meet glycemic targets if there are no concerns for or indications of SGA.

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

Background:

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

Objective:

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

Materials and Methods:

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

Results:

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

Conclusion:

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

Impact of patient education on KAP, medication adherence and therapeutic outcomes of metformin versus insulin therapy in patients with gestational diabetes: A Hospital based pilot study in South India

BACKGROUND AND AIM

The study assessed the impact of continuous patient education on Knowledge, Attitude, Practice (KAP), medication adherence and extent of glycemic control in pregnant women with gestational diabetes on insulin or metformin therapy.

METHODS

81 women with gestational diabetes (37 on insulin and 44 on metformin) were assessed for KAP using a validated questionnaire and medication adherence using the 8-items Morisky medication adherence scale, fasting, and postprandial blood glucose levels at the baseline and after two education sessions on drug therapy at one and three months intervals. The difference in mean KAP, medication adherence scores, fasting, and postprandial blood glucose levels and the extent of glycemic control with insulin or metformin therapy were assessed statistically.

RESULTS

There was a highly significant difference in the mean KAP, medication adherence scores, fasting and postprandial blood glucose levels from baseline to follow-up after three months, (P < 0.0001) indicating that continuous patient education had a positive impact on their KAP, medication adherence, blood glucose levels.

CONCLUSION

The study identified that continuous patient education improved their knowledge and practice of medication adherence which reflected on lowered fasting and postprandial blood glucose levels. Glycemic control was found to be the same with metformin and insulin in gestational diabetes.

O impacto do uso da metformina para gestantes obesas na prevenção da pré-eclâmpsia

Objetivos: o artigo objetiva avaliar o uso de metformina em gestantes obesas na prevenção da pré-eclâmpsia.Métodos: trata-se de um ensaio clínico randomizado com mulheres grávidas obesas com índice de massa corporal superior ou igual a 30 kg/m2 divididos em dois grupos – um grupo de estudo, que utilizou metformina, e um grupo controle, que seguiu a rotina de pré-natal. As gestantes entraram no estudo com idade gestacional menor que 20 semanas e foram acompanhadas durante todo o período pré-natal. O diagnóstico de pré-eclâmpsia foi feito de acordo com os critérios da Organização Mundial de Saúde.Resultados: verificou-se a redução de risco absoluto e o número necessário para tratar em um intervalo de confiança de 95% para o resultado pré-eclâmpsia. Nos resultados, 272 gestantes foram avaliadas. No grupo de estudo (n = 127), oito (6,3%) desenvolveram pré-eclâmpsia. No grupo controle (n = 145), 31 (21,4%) tiveram a doença (p <0,01).Conclusão: o estudo apontou uma redução de risco absoluto de 15,1 vezes (IC95%: 7,1-22,9) e número necessário para tratar de sete (IC95%: 4,4-13,9). O uso de 1000 miligramas diárias de metformina indicou uma redução de 15,1 vezes no risco absoluto de pré-eclâmpsia na população estudada, com a necessidade de tratar sete gestantes para evitar um desfecho.

Insulin Therapy in Pregnancy Hypertensive Diseases and its Effect on the Offspring and Mother Later in Life

Pregnancy hypertensive disorders such as Preeclampsia (PE) are strongly correlated with insulin resistance, a condition in which the metabolic handling of D-glucose is deficient. In addition, the impact of preeclampsia is enhanced by other insulin-resistant disorders, including polycystic ovary syndrome and obesity. For this reason, there is a clear association between maternal insulin resistance, polycystic ovary syndrome, obesity and the development of PE. However, whether PE is a consequence or the cause of these disorders is still unclear. Insulin therapy is usually recommended to pregnant women with diabetes mellitus when dietary and lifestyle measures have failed. The advantage of insulin therapy for Gestational Diabetes Mellitus (GDM) patients with hypertension is still controversial; surprisingly, there are no studies in which insulin therapy has been used in patients with hypertension in pregnancy without or with an established GDM. This review is focused on the use of insulin therapy in hypertensive disorders in the pregnancy and its effect on offspring and mother later in life. PubMed and relevant medical databases have been screened for literature covering research in the field especially in the last 5-10 years.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

Effect of Metformin on a Preeclampsia-Like Mouse Model Induced by High-Fat Diet

BACKGROUND

Metformin has been reported to decrease insulin resistance and is associated with a lower risk of pregnancy-induced hypertension and preeclampsia. It is widely accepted that the placenta plays a crucial role in the development of preeclampsia. Our aim is to explore the effect of metformin on preeclampsia.

STUDY DESIGN

We examined control diet-fed (isocaloric diet) pregnant mice (CTRL group), pregnant mice fed a high-fat diet (HF group), and high-fat-diet-fed pregnant mice treated with metformin (HF-M group). The HF mice were fed a high-fat diet six weeks before pregnancy to establish a preeclampsia-like model; then, the group was randomly divided into a HF group and a HF-M group after pregnancy. Blood pressure, urine protein, pregnancy outcomes, protein expression, and histopathological changes in the placentas of all groups were examined and statistically analysed.

RESULTS

We observed that metformin significantly improved high blood pressure, proteinuria, and foetal and placental weights in the HF-M group compared with the HF group. Metformin significantly improved placental labyrinth and foetal vascular development in preeclampsia. In addition, metformin effectively increased matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) levels in the placenta.

CONCLUSIONS

Our results suggest that metformin can improve preeclamptic symptoms and pregnancy outcomes.

Metformin decreases hyaluronan synthesis by vascular smooth muscle cells

Metformin is the first-line drug in the treatment of type 2 diabetes worldwide based on its effectiveness and cardiovascular safety. Currently metformin is increasingly used during pregnancy in women with gestational diabetes mellitus, even if the long-term effects of metformin on offspring are not exactly known. We have previously shown that high glucose concentration increases hyaluronan (HA) production of cultured human vascular smooth muscle cells (VSMC) via stimulating the expression of hyaluronan synthase 2 (HAS2). This offers a potential mechanism whereby hyperglycemia leads to vascular macroangiopathy. In this study, we examined whether gestational metformin use affects HA content in the aortic wall of mouse offspring in vivo. We also examined the effect of metformin on HA synthesis by cultured human VSMCs in vitro. We found that gestational metformin use significantly decreased HA content in the intima-media of mouse offspring aortas. In accordance with this, the synthesis of HA by VSMCs was also significantly decreased in response to treatment with metformin. This decrease in HA synthesis was shown to be due to the reduction of both the expression of HAS2 and the amount of HAS substrates, particularly UDP-N-acetylglucosamine. As shown here, gestational metformin use is capable to program reduced HA content in the vascular wall of the offspring strongly supporting the idea, that metformin possesses long-term vasculoprotective effects.

Comparative effects of glibenclamide, metformin and insulin on fetal pancreatic histology and maternal blood glucose in pregnant streptozotocin-induced diabetic rats

BACKGROUND

Oral hypoglycemic agents use during pregnancy was assumed to cause fetal macrosomia and skeletal deformities, and maternal complications due to significant transfer across placenta or ineffective control of blood glucose.

OBJECTIVE

This study investigated effects of insulin, metformin and glibenclamide on maternal blood glucose; and fetal crown-rump length, gross malformation and pancreatic histology in pregnant streptozotocin-induced diabetic rats.

METHODS

Twenty-five pregnant rats of groups 1 to 5 as normal and diabetic controls; and diabetic treated with insulin, metformin and glibenclamide were used. Experimental GDM was induced using 45 and 35mg/Kgbw of intraperitoneal streptozotocin.

RESULTS

Metformin, Insulin and Glibenclamide significantly reduced maternal glucose by 140.6mg/dL, 103.2mg/dL and 98.54mg/dl; respectively and showed islets with regular interlobular ducts, islets with some irregular interlobular ducts, and islets with many irregular interlobular ducts in histological fetal pancreatic photomicrographs respectively. This depicts metformin having highest ameliorative effect. There were no significant differences in maternal and fetal body weights, maternal blood glucose between diabetic groups, and fetal gross examination.

CONCLUSION

At the doses used in this research, metformin and glibenclamide showed no adverse effects on maternal and fetal features in the treatment of GDM. Thus, they can be used as safe and inexpensive alternatives to insulin.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Metformin-treated-GDM has lower risk of macrosomia compared to diet-treated GDM- a retrospective cohort study

Background: The diagnosis of gestational diabetes (GDM) has undergone several revisions. The broad adoption of the 2013 WHO criteria for hyperglycemia in pregnancy has increased the prevalence of GDM with no apparent benefit on pregnancy outcomes. The study aims to investigate the pregnancy outcomes in women with GDM diagnosed based on the WHO criteria compared to a control group; the impact of other confounders; and the difference in outcomes between GDM women who needed pharmacotherapy (GDM-T) and those who did not (GDM-D).Methods: This is a retrospective cohort study that included GDM women compared to normoglycemic controls between March 2015 and December 2016 in the Women's Hospital, Qatar.Results: The study included 2221 women; of which 1420 were normoglycemic, and 801 were GDM (358 GDM-D and 443 GDM-T). At conception, GDM women were older (mean age 32.5 ± 5.4 versus 29.6 ± 5.6 years, p<.001) and had higher prepregnancy BMI (mean BMI 32.2 ± 6.2 versus 28.2 ± 6.1 kg/m2, p<.01) compared to the controls, respectively. After correction for age, prepregnancy weight, and gestational weight gain (GWG); women with GDM had a higher risk of preterm labor (OR: 1.72; 95% CI: 1.32-2.23), large for gestational age (GA) (OR: 1.67; 95% CI: 1.22-2.29), neonatal ICU admission (OR: 1.57; 95% CI: 1.15-2.13), and neonatal hypoglycemia (OR: 3.22; 95% CI: 2.06-5.03). At conception, GDM-T women were older (mean age 33.3 ± 5.0 versus 31.5 ± 5.7 years, p<.001) and had higher BMI (mean BMI 32.9 ± 6.3 versus 231.2 ± 6.0 kg/m2, p=.01) compared to GDM-D, respectively. Metformin was used in 90.7% of the GDM-T women. Women in the GDM-T group had lower GWG/week compared to GDM-D (-0.01 ± 0.7 versus 0.21 ± 0.5 kg/week; p<.001). After correcting for age, prepregnancy weight and GWG; GDM-T had a higher risk of preterm labor (OR: 1.66; 95% CI: 1.20-2.22), and C-section (OR: 1.37, 95% CI: 1.02-1.85) and reduced risk of macrosomia (OR: 0.56; 95% CI: 0.32-0.96) and neonatal hypoglycemia (OR: 0.49; 95% CI: 0.28-0.82).Conclusion: In addition to hyperglycemia, the adverse effects of GDM on pregnancy outcomes are multifactorial and includes maternal age, maternal obesity, and gestational weight gain. Treatment with metformin reduces maternal weight gain, the risk of macrosomia and neonatal hypoglycemia compared to diet alone.

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.

Can Nurse-Based Management Screening Ensure Adequate Outcomes in Patients With Gestational Diabetes? A Comparison of 2 Organizational Models

BACKGROUND

Gestational diabetes mellitus (GDM) is an impaired glucose tolerance with onset or first recognition during pregnancy. The purpose of this study is to evaluate the clinical outcomes of a blood glucose monitoring protocol implemented by nurses and dietitians in a diabetes team to the previously established protocol of direct monitoring of GDM patients by a diabetologist.

METHODS

Two groups of patients were formed: The first group was based on a traditional protocol (P1: 230 patients) with patients' blood glucose constantly checked by a diabetologist. In the second structured group (P2: 220 patients) patients were referred to a diabetologist only if they required insulin therapy.

RESULTS

The number of medical visits (P2: 1.28 ± 0.70 vs P1: 3.27 ± 1.44; P < .001) and the percentage of patients with hypoglycemia (P2: 6.8% vs P1: 15.2%; P < .006) were found to be lower in group P2 than in group P1. In both groups, a direct relationship was found between a parental history of diabetes and the risk of GDM (odds ratio [OR]: P1 = 2.2 [1.17-4.12]; P2 = 2.5 [1.26-5.12]). In group P1, it was observed that hyperweight gain in patients who were already overweight before becoming pregnant significantly increased the risk of macrosomia (OR: 3.11 [1.39-25.7]), whereas this was not detected in patients in group P2. In group P2, a correlation was found between macrosomia and insulin therapy (OR: 0.066 vs 0.34). In group P1 and group P2, a correlation was observed between insulin therapy and a family history of diabetes (OR: 2.20 vs 2.27), and a body mass index of greater than 30 kg/m in group P2 (OR: 3.0 vs 1.47).

CONCLUSIONS

The data we collected show that creating a structured protocol for GDM management reduces the number of medical visits required by patients without increasing the risk of hypoglycemia, macrosomia, or hyperweight gain during pregnancy.

Prenatal metformin exposure or organic cation transporter 3 knock-out curbs social interaction preference in male mice

Poorly managed gestational diabetes can lead to severe complications for mother and child including fetal overgrowth, neonatal hypoglycemia and increased autism risk. Use of metformin to control it is relatively new and promising. Yet safety concerns regarding gestational metformin use remain, as its long-term effects in offspring are unclear. In light of beneficial findings with metformin for adult mouse social behavior, we hypothesized gestational metformin treatment might also promote offspring sociability. To test this, metformin was administered to non-diabetic, lean C57BL/6 J female mice at mating, with treatment discontinued at birth or wean. Male offspring exposed to metformin through birth lost social interaction preference relative to controls by time in chambers, but not by sniffing measures. Further, prenatal metformin exposure appeared to enhance social novelty preference only in females. However due to unbalanced litters and lack of statistical power, firm establishment of any sex-dependency of metformin's effects on sociability was not possible. Since organic cation transporter 3 (OCT3) transports metformin and is dense in placenta, social preferences of OCT3 knock-out males were measured. Relative to wild-type, OCT3 knock-outs had reduced interaction preference. Our data indicate gestational metformin exposure under non-diabetic conditions, or lack of OCT3, can impair social behavior in male C57BL6/J mice. Since OCT3 transports serotonin and tryptophan, impaired placental OCT3 function is one common mechanism that could persistently impact central serotonin systems and social behavior. Yet no gross alterations in serotonergic function were evident by measure of serotonin transporter density in OCT3, or serotonin turnover in metformin-exposed offspring brains. Mechanisms underlying the behavioral outcomes, and if with gestational diabetes the same would occur, remain unclear. Metformin's impacts on placental transporters and serotonin metabolism or AMPK activity in fetal brain need further investigation to clarify benefits and risks to offspring sociability from use of metformin to treat gestational diabetes.

Longer-term outcomes in offspring of GDM mothers treated with metformin versus insulin

Insulin has traditionally been the gold standard pharmacological treatment for gestational diabetes mellitus (GDM). Insulin requires multiple injections a day, can cause frequent hypoglycaemia, requires careful handling, and is generally more expensive compared to oral agents. Metformin has been increasingly popular in recent years. Based on the short-term data available, metformin appears to be safe and effective for the treatment of GDM but existing studies have all stressed the lack of longer-term offspring data. This article will analyse the evidence available on the longer-term outcomes in the offspring of women with GDM treated with metformin versus insulin. Pubmed, EMBASE, CENTRAL, and CNKI were searched for follow-up studies of randomised controlled trials that compared metformin with insulin for the treatment of GDM. Existing follow-up studies did not find any significant increase in the risk of adverse effects in terms of growth and development in the offspring of GDM mothers managed with metformin versus insulin.

Gestational diabetes mellitus: Multi-disciplinary treatment approaches

Gestational diabetes mellitus (GDM) is the most common metabolic disease of pregnancy, associated with several perinatal complications. Adequate glycemic control has been proved to decrease risk of GDM-related complications. Several studies have shown the beneficial effect of exercise and medical nutrition treatment on glycemic and weight control in GDM-affected women. Moreover, pharmacological agents, such as insulin and specific oral anti-diabetic agents can be prescribed safely during pregnancy, decreasing maternal blood glucose and, thus, perinatal adverse outcomes. Multi-disciplinary treatment approaches that include both lifestyle modifications (medical nutritional therapy and daily physical exercise) and pharmacological treatment, in cases of failure of the former, constitute the most effective approach. Insulin is the gold standard pharmacological agent for GDM treatment. Metformin and glyburide are two oral anti-diabetic agents that could serve as alternative, although not equal in terms of effectiveness and safety, treatment for GDM. As studies on short-term safety of metformin are reassuring, in some countries it is considered as first-line treatment for GDM management. More studies are needed to investigate the long-term effects on offspring. As safety issues have been raised on the use of glyburide during pregnancy, it must be used only when benefits surpass possible risks.

Endothelial function and dysfunction: Impact of metformin

Cardiovascular and metabolic diseases remain the leading cause of morbidity and mortality worldwide. Endothelial dysfunction is a key player in the initiation and progression of cardiovascular and metabolic diseases. Current evidence suggests that the anti-diabetic drug metformin improves insulin resistance and protects against endothelial dysfunction in the vasculature. Hereby, we provide a timely review on the protective effects and molecular mechanisms of metformin in preventing endothelial dysfunction and cardiovascular and metabolic diseases.

Pregnancy outcome after first-trimester exposure to metformin: A prospective cohort study

The aim of this study was to evaluate the risk of major birth defects and spontaneous abortion after metformin use during the first trimester of pregnancy. We conducted an observational cohort study comparing pregnancies with metformin treatment during the first trimester with non-exposed women matched for BMI and year of enrolment. Pregnancies were prospectively ascertained in the German Embryotox pharmacovigilance database between 2004 and 2014. The study sample included 336 pregnancies with metformin exposure for PCOS and fertility disorders (56.8%), diabetes (25.9%) and insulin resistance (14.9%) and 1011 matched controls. Independent of the treatment indication, neither the rate of major birth defects (OR adjusted 0.58, 95% CI 0.3-1.3) nor of spontaneous abortions (HR adjusted 0.95, 95% CI 0.6-1.5) was significantly increased among metformin exposed. Our study supports the evidence that metformin does not carry a developmental risk for the fetus when used during the first trimester.

Intrauterine exposure to metformin: Evaluation of endothelial and perivascular adipose tissue function in abdominal aorta of adult offspring

The biguanide metformin (MET) has been used during pregnancy for treatment of polycystic ovary syndrome and gestational diabetes. MET crosses the placenta and maternal treatment can expose the progeny to this drug during important phases of body development. Direct vascular protective effects have been described with the treatment of metformin. Nevertheless, it is unclear whether intrauterine exposure to metformin is safe for the vascular system of offspring. Thus, the present study aimed to investigate the intrinsic effects of metformin exposure in utero in the offspring abdominal aorta reactivity, in the presence and absence of perivascular adipose tissue (PVAT) and endothelium. For this, Wistar rats were treated with metformin 293 mg/kg/day (MET) or water (CTR) by gavage during the gestational period. The abdominal aorta reactivity to phenylephrine, acetylcholine, and sodium nitroprusside was evaluated in male adult offspring. It was observed that abdominal aorta relaxation was similar between MET and CTR groups in the presence or absence of PVAT. In addition, the contraction to phenylephrine was similar between MET and CTR groups in the presence and absence of PVAT and endothelium. Therefore, metformin exposure during pregnancy had no intrinsic effect on the offspring abdominal aorta PVAT and endothelial function, demonstrating it to be safe to the vascular system of the offspring.

Outcomes for Women with Gestational Diabetes Treated with Metformin: A Retrospective, Case-Control Study

Metformin is increasingly being used a therapeutic option for the management of gestational diabetes mellitus (GDM). The aim of this study was to compare the maternal characteristics and perinatal outcomes of women with GDM treated with metformin (with or without supplemental insulin) with those receiving other management approaches. A retrospective, case-control study was carried out and 83 women taking metformin were matched 1:1 with women receiving insulin or diet and lifestyle modification alone. Women managed with diet and lifestyle modification had a significantly lower fasting plasma glucose (p < 0.001) and HbA1c (p < 0.01) at diagnosis of GDM. Furthermore, women managed with metformin had a higher early pregnancy body mass index (BMI) compared to those receiving insulin or diet and lifestyle modification (p < 0.001). There was no difference in mode of delivery, birth weight or incidence of large- or small-for-gestational-age neonates between groups. Women receiving glucose lowering therapies had a higher rate of neonatal hypoglycaemia (p < 0.05). The incidence of other adverse perinatal outcomes was similar between groups. Despite their greater BMI, women with metformin-treated GDM did not have an increased risk of adverse perinatal outcomes. Metformin is a useful alternative to insulin in the management of GDM.

Pregnancy outcomes in women on metformin for diabetes or other indications among those seeking teratology information services

AIMS

Metformin is used to treat type 2 diabetes, polycystic ovary syndrome associated infertility, and gestational diabetes. This study aims to evaluate the safety of metformin in early pregnancy.

METHOD

We evaluated the risk of major birth defects and pregnancy losses in a cohort of pregnant women exposed to metformin during the first trimester for different indications relative to a matched unexposed reference group.

RESULTS

The risk of major birth defects was 5.1% (20/392) in pregnancies exposed to metformin during the first trimester and 2.1% (9/431) in the reference group [adjusted odds ratio (OR) 1.70; 95% CI 0.70-4.38]. Among metformin users, this risk was 7.8% (17/219) in patients with pre-gestational diabetes and 1.7% (3/173) in those without this diagnosis. Compared to the unexposed reference, the OR for metformin user with diabetes was 3.95 (95% CI 1.77-9.41) and for metformin with other indications it was 0.83 (95% CI 0.18-2.81). The risk of pregnancy losses (spontaneous abortions and stillbirths) was 20.8% in women on metformin during the first trimester and 10.8% in the reference group [adjusted hazard ratio (HR) 1.57; 95% CI 0.90-2.74]. The risks for women on metformin with and without pre-gestational diabetes were 24.0% and 16.8% respectively, with adjusted HR of 2.51 (95% CI 1.44-4.36) and 1.38 (95% CI 0.74-2.59) when compared to the reference.

CONCLUSION

Pregnant women with pre-gestational diabetes on metformin are at a higher risk for adverse pregnancy outcomes than the general population. This appears to be due to the underlying diabetes since women on metformin for other indications do not present meaningfully increased risks.

Metformin in gestational diabetes: the offspring follow-up (MiG TOFU): body composition and metabolic outcomes at 7-9 years of age

OBJECTIVE

To compare body composition and metabolic outcomes at 7-9 years in offspring of women with gestational diabetes (GDM) randomized to metformin (±insulin) or insulin treatment during pregnancy.

RESEARCH DESIGN AND METHODS

Children were assessed at 7 years in Adelaide (n=109/181) and 9 years in Auckland (n=99/396) by anthropometry, bioimpedance analysis (BIA), dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI) (n=92/99) and fasting bloods (n=82/99).

RESULTS

In the Adelaide subgroup, mothers were similar at enrollment. Women randomized to metformin versus insulin had higher treatment glycemia (p=0.002) and more infants with birth weight >90th percentile (20.7% vs 5.9%; p=0.029). At 7 years, there were no differences in offspring measures. In Auckland, at enrollment, women randomized to metformin had a higher body mass index (BMI) (p=0.08) but gained less weight during treatment (p=0.07). Offspring birth measures were similar. At 9 years, metformin offspring were larger by measures of weight, arm and waist circumferences, waist:height (p<0.05); BMI, triceps skinfold (p=0.05); DXA fat mass and lean mass (p=0.07); MRI abdominal fat volume (p=0.051). Body fat percent was similar between treatment groups by DXA and BIA. Abdominal fat percentages (visceral adipose tissue, subcutaneous adipose tissue and liver) were similar by MRI. Fasting glucose, triglyceride, insulin, insulin resistance, glycosylated hemoglobin (HbA1c), cholesterol, liver transaminases, leptin and adiponectin were similar.

CONCLUSIONS

Metformin or insulin for GDM was associated with similar offspring total and abdominal body fat percent and metabolic measures at 7-9 years. Metformin-exposed children were larger at 9 years. Metformin may interact with fetal environmental factors to influence offspring outcomes.

Treatments for gestational diabetes: a systematic review and meta-analysis

OBJECTIVE

To investigate the effectiveness of different treatments for gestational diabetes mellitus (GDM).

DESIGN

Systematic review, meta-analysis and network meta-analysis.

METHODS

Data sources were searched up to July 2016 and included MEDLINE and Embase. Randomised trials comparing treatments for GDM (packages of care (dietary and lifestyle interventions with pharmacological treatments as required), insulin, metformin, glibenclamide (glyburide)) were selected by two authors and double checked for accuracy. Outcomes included large for gestational age, shoulder dystocia, neonatal hypoglycaemia, caesarean section and pre-eclampsia. We pooled data using random-effects meta-analyses and used Bayesian network meta-analysis to compare pharmacological treatments (ie, including treatments not directly compared within a trial).

RESULTS

Forty-two trials were included, the reporting of which was generally poor with unclear or high risk of bias. Packages of care varied in their composition and reduced the risk of most adverse perinatal outcomes compared with routine care (eg, large for gestational age: relative risk0.58 (95% CI 0.49 to 0.68; I2=0%; trials 8; participants 3462). Network meta-analyses suggest that metformin had the highest probability of being the most effective treatment in reducing the risk of most outcomes compared with insulin or glibenclamide.

CONCLUSIONS

Evidence shows that packages of care are effective in reducing the risk of most adverse perinatal outcomes. However, trials often include few women, are poorly reported with unclear or high risk of bias and report few outcomes. The contribution of each treatment within the packages of care remains unclear. Large well-designed and well-conducted trials are urgently needed.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42013004608.

The emerging role of metformin in gestational diabetes mellitus

Metformin use during pregnancy is controversial and there is disparity in the acceptance of metformin treatment in women with gestational diabetes mellitus (GDM) in Australia. Despite short term maternal and neonatal safety measures, the placental transfer of metformin during GDM treatment and the absence of long-term safety data in offspring has regulators and prescribers cautious about its use. To determine the current role in GDM management, this literature review describes the physiological changes that occur in GDM and other forms of diabetes in pregnancy (DIP) and international changes in guidelines for GDM diagnosis. Management options are considered, with a focus on the evolving evidence for metformin, its mechanism of action, the maternal, foetal and neonatal outcomes associated with its use and benefit vs risk when compared with the current gold standard, insulin. Investigation reveals a favourable balance of evidence to support the safety and long-term benefits, to mother and child, of using metformin as an alternate to insulin for treatment of GDM. Recent findings of the gastrointestinal-directed action of metformin are at least as important as the hepatic effect and the availability of a novel delayed-release metformin dose form to exploit this new information provides a product and therapeutic strategy ideally suited to the use of metformin in GDM.

Genomic Characterization of Metformin Hepatic Response

Metformin is used as a first-line therapy for type 2 diabetes (T2D) and prescribed for numerous other diseases. However, its mechanism of action in the liver has yet to be characterized in a systematic manner. To comprehensively identify genes and regulatory elements associated with metformin treatment, we carried out RNA-seq and ChIP-seq (H3K27ac, H3K27me3) on primary human hepatocytes from the same donor treated with vehicle control, metformin or metformin and compound C, an AMP-activated protein kinase (AMPK) inhibitor (allowing to identify AMPK-independent pathways). We identified thousands of metformin responsive AMPK-dependent and AMPK-independent differentially expressed genes and regulatory elements. We functionally validated several elements for metformin-induced promoter and enhancer activity. These include an enhancer in an ataxia telangiectasia mutated (ATM) intron that has SNPs in linkage disequilibrium with a metformin treatment response GWAS lead SNP (rs11212617) that showed increased enhancer activity for the associated haplotype. Expression quantitative trait locus (eQTL) liver analysis and CRISPR activation suggest that this enhancer could be regulating ATM, which has a known role in AMPK activation, and potentially also EXPH5 and DDX10, its neighboring genes. Using ChIP-seq and siRNA knockdown, we further show that activating transcription factor 3 (ATF3), our top metformin upregulated AMPK-dependent gene, could have an important role in gluconeogenesis repression. Our findings provide a genome-wide representation of metformin hepatic response, highlight important sequences that could be associated with interindividual variability in glycemic response to metformin and identify novel T2D treatment candidates.

Metformin is among the most widely prescribed drugs. It is used as a first line therapy for type 2 diabetes (T2D), and for additional diseases including cancer. The variability in response to metformin is substantial and can be caused by genetic factors. However, the molecular mechanisms of metformin action are not fully known. Here, we used various genomic assays to analyze human liver cells treated with or without metformin and identified in a genome-wide manner thousands of differentially expressed genes and gene regulatory elements affected by metformin. Follow up functional assays identified several novel genes and regulatory elements to be associated with metformin response. These include ATF3, a gene that showed gluconeogenesis repression upon metformin response and a potential regulatory element of the ATM gene that is associated with metformin treatment differences through genome-wide association studies. Combined, this work identifies several novel genes and gene regulatory elements that can be activated due to metformin treatment and thus provides candidate sequences in the human genome where nucleotide variation can lead to differences in metformin response. It also enables the identification and prioritization of novel candidates for T2D treatment.

Gestational Diabetes Mellitus:current knowledge and unmet needs

Gestational diabetes mellitus (GDM) is a global health concern, not only because its prevalence is high and on the increase, but also because of the potential implications for the health of mothers and their offspring. Unfortunately, there is considerable controversy in the literature surrounding the diagnosis and treatment of GDM, as well as the possible long-term consequences for the offspring. As a result, worldwide there is a lack of uniformly accepted diagnostic criteria and the advice regarding the treatment of GDM, including diet, insulin therapy, and the use of oral blood glucose-lowering agents, is highly variable. In this review we provide an overview of the important issues in the field of GDM, including diagnostic criteria, different treatment regimens available, and the long-term consequences of GDM in the offspring.

Efficacy and safety of metformin for the treatment of gestational diabetes: a new approach to the problem

Historically, the following two methods were used to treat gestational diabetes mellitus: non-medical life-style interventions (diet and increased physical activity) and insulin treatment when other interventions were not effective. The possibility of alternative types of treatment such as oral anti-diabetic drugs has been the source of debate in recent years. Metformin is an oral anti-diabetic drug that reduces insulin resistance, which is common during gestation and is considered one of the main pathways of glucose metabolism alteration during pregnancy. The main concern is that metformin can cross the placenta and is found unchanged in foetal blood. This is the reason why oral anti-diabetic drugs are contraindicated during pregnancy in many countries, including Russia (according to the 2012 Russian recommendations for gestational diabetes treatment). In recent years, many studies investigating the safety and efficacy of metformin for maternal and foetal health have been published. We will review recent randomized clinical trials and discuss new international clinical recommendations (FIGO, 2015) and new opportunities for gestational diabetes mellitus treatment. 

Complications in neonates of mothers with gestational diabetes mellitus receiving insulin therapy versus dietary regimen

BACKGROUND

Gestational diabetes mellitus (GDM) is a common obstetrical complication with both maternal and fetal side effects.

OBJECTIVE

This study was performed to determine the complications in neonates of mothers with GDM receiving insulin vs. dietary regimen.

MATERIALS AND METHODS

In this prospective cohort study, 140 neonates of mothers with GDM attending Javaheri Hospital of Azad University in Tehran in 2013 and 2014 were enrolled and the complications in those receiving insulin versus. dietary regimen were compared.

RESULTS

The results demonstrated that 95.7% of those who received a dietary regimen and 85.7% among those who received insulin had a good outcome showing statistically significant differences (p=0.042). The mortality rate was not differed among the patients in two groups (p>0.05).

CONCLUSION

According to the results of this study, it may be concluded that the frequency of complications in neonates of cases with GDM is getting less by receiving dietary regimen.

GESTATIONAL DIABETES. OBSTETRICAL PERSPECTIVE

This review discusses current international recommendations for GDM diagnosis and management and argues whether it would be worth considering first, universal screening for GDM in our country, second, updating of management guidelines and third, organized follow-up of women diagnosed with GDM and adoption of lifestyle interventions after delivery that could reduce the onset and prevalence of type 2 DM.