Metformin in gestational diabetes: the offspring follow-up (MiG TOFU): body composition at 2 years of age

Nutritional programming of insulin resistance: causes and consequences

Strong evidence indicates that adverse prenatal and early postnatal environments have a significant long-term influence on risk factors that result in insulin resistance, type 2 diabetes (T2D), and cardiovascular disease later in life. Here we discuss current knowledge of how maternal and neonatal nutrition influence early growth and the long-term risk of developing insulin resistance in different organs and at the whole-body level. Accumulating evidence supports a role for epigenetic mechanisms underlying this nutritional programming, consisting of heritable changes that regulate gene expression which in turn shapes the phenotype across generations. Deciphering these molecular mechanisms in key tissues and discovering key biological markers may provide valuable insight towards the development of effective intervention strategies.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Preditores de sucesso da metformina no tratamento do diabetes mellitus gestacional

OBJETIVOS: identificar características maternas relacionadas à falha no tratamento do diabetes mellitus gestacional (DMG) com metformina. MÉTODOS: estudo retrospectivo observacional (julho/2008-setembro/ 2010), com 104 gestantes com DMG que necessitaram de terapêutica complementar a dietoterapia e utilizaram metformina. Dividiram-se em dois grupos: sucesso terapêutico (n=82), onde a droga foi mantida até o parto; outro com falha terapêutica (n=22) onde a droga foi substituída por insulina. Variáveis maternas estudadas: idade, número de partos, ganho de peso na gestação, glicemia de jejum (GJ) e 2h no OGTT75g, idade gestacional de diagnóstico de DMG (IGDMG). Variáveis do recém nascido: incidência de RNs GIG e hipoglicemia neonatal. Foram comparadas as características clínico-metabólicas maternas e os resultados perinatais, o nível de significância utilizado foi de 5%. RESULTADOS: apresentaram diferença na IGDMG (27,5 vs 24,3 semanas; p=0,02), no índice de massa corporal (IMC) (27,5 vs 31,6 kg/m²; p=0,01), e GJ no OGTT75g (91,5 vs 108 mg/dL; p=0,02), nos grupos de sucesso e falha respectivamente. A falha terapêutica aumentou o índice ponderal dos RNs (2,8 vs 3 g/cm³; p=0,05), incidência de RNs GIG (4,9 vs 22,7%; p=0,02) e hipoglicemia neonatal (6,1 vs 18,2%; p=0,04). Os dados dos RNs foram objetivos secundários. CONCLUSÕES: o diagnóstico precoce, o maior IMC e maior GJ OGTT75g estiveram mais relacionados a falha terapêutica.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Maternal obesity: how big an impact does it have on offspring prenatally and during postnatal life?

Obesity is increasing at an epidemic rate in women of reproductive age. Not only does obesity during pregnancy lead to increased maternal health concerns, it is also linked to an increase in adiposity and components of the metabolic syndrome in the children and grandchildren of obese women. The potential transgenerational impact of maternal obesity on the health of future generations will undoubtedly result in increasing healthcare costs for society. This review will describe what is known about the specific impacts of maternal obesity on offspring in the human population as well as discuss how controlled animal experiments have shed light on the specific physiological mechanisms involved. Furthermore, preliminary experiments are presented describing potential dietary methods for preventing obesity-induced programming of offspring health concerns in postnatal life.

Transfer of metformin across the rat placenta is mediated by organic cation transporter 3 (OCT3/SLC22A3) and multidrug and toxin extrusion 1 (MATE1/SLC47A1) protein

In our previous studies we described functional expression of organic cation transporter 3 (OCT3) and multidrug and toxin extrusion 1 (MATE1) protein in the rat placenta. Since metformin is a substrate of both OCT3 and MATE1, in this study we used the model of dually perfused rat placenta to investigate the role of these transporters in metformin passage across the placenta. We observed concentration-dependent transplacental clearance of metformin in both maternal-to-fetal and fetal-to-maternal directions; in addition metformin crossed the placenta from the fetal to maternal compartment even against its concentration gradient. This transport was completely inhibited by MPP(+), a common OCT3 and MATE1 inhibitor. Furthermore, we observed that the oppositely directed H(+)-gradient can drive the secretion of metformin from placenta to maternal circulation, confirming apical efflux of metformin from trophoblast by MATE1. In conclusion, we suggest an important role of OCT3 and MATE1 in the transplacental transfer of metformin.

Oral Hypoglycemic Agents in pregnancy: An Update

INTRODUCTION

Traditionally, insulin has been the gold standard in the management of Type 2 diabetes in pregnancy and gestational diabetes. However, insulin therapy can be inconvenient because of the needs for multiple injections, its associated cost, pain at the injection site, need for refrigeration, and skillful handling of the syringes. This has led to the exploration of oral hypoglycemic agents as an alternative to insulin therapy.

OBJECTIVES

This review examines and evaluates the evidences on the efficacy, safety, and current recommendations of oral hypoglycemic agents.

CONCLUSION

The evidence of this study supports the use of glyburide and metformin in the management of Type 2 diabetes and gestational diabetes with no increased risk of neonatal hypoglycemia or congenital anomalies. The safety of these oral hypoglycemic agents are limited to the prenatal period and more randomized controlled trials are required to provide information on the long-term follow up on neonatal and cognitive development.

Is the evidence strong enough to change the diagnostic criteria for gestational diabetes now?

The International Association of the Diabetes and Pregnancy Study Groups has proposed new thresholds for oral glucose tolerance tests that are based on the large observational Hyperglycemia and Adverse Pregnancy Outcomes study. By using these criteria about 18% of pregnant women will be diagnosed as having gestational diabetes mellitus. The question arises if we are ready for such an enormous increase in gestational diabetes mellitus patients, if outcome would really improve by using these criteria, and if additional studies are necessary before deciding on new diagnostic thresholds. In this clinical opinion, the pros and cons will be discussed.

Maternal and neonatal circulating markers of metabolic and cardiovascular risk in the metformin in gestational diabetes (MiG) trial: responses to maternal metformin versus insulin treatment

OBJECTIVE

This study was designed to compare glucose, lipids, and C-reactive protein (CRP) in women with gestational diabetes mellitus treated with metformin or insulin and in cord plasma of their offspring and to examine how these markers relate to infant size at birth.

RESEARCH DESIGN AND METHODS

Women with gestational diabetes mellitus were randomly assigned to metformin or insulin in the Metformin in Gestational Diabetes trial. Fasting maternal plasma glucose, lipids, and CRP were measured at randomization, 36 weeks' gestation, and 6-8 weeks postpartum as well as in cord plasma. Women with available cord blood samples (metformin n = 236, insulin n = 242) were included.

RESULTS

Maternal plasma triglycerides increased more from randomization to 36 weeks' gestation in women treated with metformin (21.93%) versus insulin (9.69%, P < 0.001). Maternal and cord plasma lipids, CRP, and neonatal anthropometry did not differ between treatments. In logistic regression analyses adjusted for confounders, the strongest associations with birth weight >90th centile were maternal triglycerides and measures of glucose control at 36 weeks.

CONCLUSIONS

There were few differences in circulating maternal and neonatal markers of metabolic status and no differences in measures of anthropometry between the offspring of women treated with metformin and the offspring of women treated with insulin. There may be subtle effects of metformin on maternal lipid function, but the findings suggest that treating gestational diabetes mellitus with metformin does not adversely affect lipids or CRP in cord plasma or neonatal anthropometric measures.

Comparison of newborn outcomes in women with gestational diabetes mellitus treated with metformin or insulin: a randomised blinded trial

BACKGROUND

Few studies have been done on the use of metformin in pregnancy and their results were not similar, therefore this research is performed to compare neonatal outcomes of metformin and insulin in the treatment of gestational diabetes.

METHODS

In this prospective randomized trial, 200 pregnant women within their 24(th) to 34(th) weeks of gestation with gestational diabetes, single fetus pregnancy, and in need of hyperglycemia treatment were entered and grouped as either metformin or insulin. Data related to maternal and neonatal outcomes were recorded and analyzed.

RESULTS

Considering data recorded of HbA1c at the beginning of pregnancy, pregnancy induced hypertension, preeclampsia, birth weight, dystocia, first and 5(th) min APGAR, neonatal sepsis, rout of delivery, liver function tests of neonate, hypoglycemia, anomaly, and still birth, there were no significant statistical differences between groups. The end pregnancy HbA1c, maternal weight gain during pregnancy, preterm labor, neonatal jaundice, respiratory distress and hospitalization of infants were higher in insulin group.

CONCLUSIONS

Considering data from this study, metformin is efficient to control hyperglycemia in pregnancy. It is suggested performing more studies to evaluate long term side effects of metformin in pregnancy with higher sample size and longer follow-up of newborns.

Metformin: an old but still the best treatment for type 2 diabetes

The management of T2DM requires aggressive treatment to achieve glycemic and cardiovascular risk factor goals. In this setting, metformin, an old and widely accepted first line agent, stands out not only for its antihyperglycemic properties but also for its effects beyond glycemic control such as improvements in endothelial dysfunction, hemostasis and oxidative stress, insulin resistance, lipid profiles, and fat redistribution. These properties may have contributed to the decrease of adverse cardiovascular outcomes otherwise not attributable to metformin's mere antihyperglycemic effects. Several other classes of oral antidiabetic agents have been recently launched, introducing the need to evaluate the role of metformin as initial therapy and in combination with these newer drugs. There is increasing evidence from in vivo and in vitro studies supporting its anti-proliferative role in cancer and possibly a neuroprotective effect. Metformin's negligible risk of hypoglycemia in monotherapy and few drug interactions of clinical relevance give this drug a high safety profile. The tolerability of metformin may be improved by using an appropiate dose titration, starting with low doses, so that side-effects can be minimized or by switching to an extended release form. We reviewed the role of metformin in the treatment of patients with type 2 diabetes and describe the additional benefits beyond its glycemic effect. We also discuss its potential role for a variety of insulin resistant and pre-diabetic states, obesity, metabolic abnormalities associated with HIV disease, gestational diabetes, cancer, and neuroprotection.

Prenatal metformin exposure in mice programs the metabolic phenotype of the offspring during a high fat diet at adulthood

AIMS

The antidiabetic drug metformin is currently used prior and during pregnancy for polycystic ovary syndrome, as well as during gestational diabetes mellitus. We investigated the effects of prenatal metformin exposure on the metabolic phenotype of the offspring during adulthood in mice.

METHODS

Metformin (300 mg/kg) or vehicle was administered orally to dams on regular diet from the embryonic day E0.5 to E17.5. Gene expression profiles in liver and brain were analysed from 4-day old offspring by microarray. Body weight development and several metabolic parameters of offspring were monitored both during regular diet (RD-phase) and high fat diet (HFD-phase). At the end of the study, two doses of metformin or vehicle were given acutely to mice at the age of 20 weeks, and Insig-1 and GLUT4 mRNA expressions in liver and fat tissue were analysed using qRT-PCR.

RESULTS

Metformin exposed fetuses were lighter at E18.5. There was no effect of metformin on the maternal body weight development or food intake. Metformin exposed offspring gained more body weight and mesenteric fat during the HFD-phase. The male offspring also had impaired glucose tolerance and elevated fasting glucose during the HFD-phase. Moreover, the expression of GLUT4 mRNA was down-regulated in epididymal fat in male offspring prenatally exposed to metformin. Based on the microarray and subsequent qRT-PCR analyses, the expression of Insig-1 was changed in the liver of neonatal mice exposed to metformin prenatally. Furthermore, metformin up-regulated the expression of Insig-1 later in development. Gene set enrichment analysis based on preliminary microarray data identified several differentially enriched pathways both in control and metformin exposed mice.

CONCLUSIONS

The present study shows that prenatal metformin exposure causes long-term programming effects on the metabolic phenotype during high fat diet in mice. This should be taken into consideration when using metformin as a therapeutic agent during pregnancy.

Bioimpedance prediction of fat-free mass from dual-energy X-ray absorptiometry in a multi-ethnic group of 2-year-old children

BACKGROUND/OBJECTIVES

Bioimpedance analysis (BIA) is a simple, convenient and widely used tool for the measurement of body composition in population surveys and surveillance. Prediction equations based on BIA applicable to preschool children are available but are based on total body water estimation and have not been developed across multiple ethnic groups. Our aim was to develop a BIA-based equation in a multi-ethnic sample of 2-year old using fat-free mass (FFM) from dual-energy X-ray absorptiometry (DXA) as criterion measure.

SUBJECTS/METHODS

Single-frequency hand-to-foot BIA (model BIM4, Impedimed) and whole-body DXA measurements were carried out in 77 (35 boys, 42 girls; 27 European, 20 Polynesian, 30 Asian and other) healthy preschool children (age range 22-38 months). Body mass index s.d. scores were 0.41 ± 1.23 for boys and 0.61 ± 1.09 for girls. The performance of published equations applicable to this age group was assessed. The predicted residual sum of squares method was used to develop and cross-validate a multiple regression equation relating FFM to BIA measures.

RESULTS

Published equations performed poorly for estimating FFM in this group of children. The prediction equation developed in all 77 children was: FFM (kg)=0.367 height(cm)(2)/resistance+0.188 weight (kg)+0.077 height (cm)+0.273 sex (male=1, female=0)-2.490, R(2)=0.89, standard error of estimate=0.50 kg. Ethnicity and age did not add significantly to the model.

CONCLUSIONS

We have developed an equation that may have application for prediction of FFM in 2-3-year-old children, which does not require determination of hydration factors. Further work should be carried out using DXA scanning to extend the applicable age range.

Fasting blood glucose predicts response to extended-release metformin in gestational diabetes mellitus

BACKGROUND

Metformin is increasingly accepted as an alternative to insulin therapy in gestational diabetes mellitus (GDM). The Metformin in Gestational Diabetes (MiG) trial reported similar pregnancy outcomes for metformin versus insulin; however, supplemental insulin was required in 46% of women on metformin.

AIMS

We aimed to identify predictors of response to metformin monotherapy in women with GDM attending a general hospital antenatal clinic.

METHODS

We offered extended-release metformin to women diagnosed with GDM (ADIPS 1998 criteria) at ≥24 weeks of gestation. If glucose targets were not achieved (≤5.0 mmol/L fasting, ≤6.7 mmol/L two-h post-meal), women were changed to insulin. We carried out an audit to determine characteristics of metformin responders versus nonresponders.

RESULTS

Twenty-five women chose initial metformin therapy; 16 (64%) achieved satisfactory glycaemic control (responders). Nine women (36%) were changed to insulin: seven due to inadequate control (nonresponders) and two had metformin intolerance. Fasting glucose at oral glucose tolerance test (OGTT) was significantly lower in metformin responders versus nonresponders; two-h glucose and BMI did not differ. Ninety-three percent of women with fasting glucose ≤5.2 mmol/L responded to metformin: conversely, at fasting glucose >5.2 mmol/L, 33% responded (P = 0.005). Neonatal outcomes were similar in metformin responders and nonresponders, women who chose initial insulin therapy (n = 25), or were diet-controlled (n = 21).

CONCLUSIONS

In women with GDM, fasting glucose on OGTT predicted response to metformin: at fasting glucose ≤5.2 mmol/L, the probability of response was 93%. Antenatal clinics should determine locally relevant predictors of response to metformin in women with GDM.

Where do conventional OADs stand

The last two decades have witnessed unprecedented activity in the field of OADs with many new drugs becoming available. Concerns with OAD include cardiovascular safety, fear about hypoglycemia, weight gain etc. In this article we attempt to review OADs , sulfonylureas in particular, in the light of the newer agents.

Gestational diabetes mellitus: risks and management during and after pregnancy

Gestational diabetes mellitus (GDM) carries a small but potentially important risk of adverse perinatal outcomes and a long-term risk of obesity and glucose intolerance in offspring. Mothers with GDM have an excess of hypertensive disorders during pregnancy and a high risk of developing diabetes mellitus thereafter. Diagnosing and treating GDM can reduce perinatal complications, but only a small fraction of pregnancies benefit. Nutritional management is the cornerstone of treatment; insulin, glyburide and metformin can be used to intensify treatment. Fetal measurements complement maternal glucose monitoring in the identification of pregnancies that require such intensification. Glucose testing shortly after delivery can stratify the short-term diabetes risk in mothers. Thereafter, annual glucose and HbA(1c) testing can detect deteriorating glycaemic control, a harbinger of future diabetes mellitus, usually type 2 diabetes mellitus. Interventions that mitigate obesity or its metabolic effects are most potent in preventing or delaying diabetes mellitus. Lifestyle modification is the primary approach; use of medications for diabetes prevention after GDM remains controversial. Family planning enables optimization of health in subsequent pregnancies. Breastfeeding may reduce obesity in children and is recommended. Families should be encouraged to help children adopt lifestyles that reduce the risk of obesity.

Metformin's effect on first-year weight gain: a follow-up study

BACKGROUND

The impact of metformin medication in pregnant women with polycystic ovary syndrome on weight gain during pregnancy and after delivery and the impact on growth of the offspring are essentially unexplored.

METHODS

This is a follow-up study of a randomized controlled trial (The Metformin treatment in pregnant PCOS women study), conducted in 11 secondary care centers. Women with PCOS were randomized to metformin (2000 mg daily) or placebo from first trimester to delivery. Questionnaires were sent to 256 participants 1 year postpartum. Maternal weight development in pregnancy and the first year after delivery and offspring anthropometry at birth and weight 1 year postpartum were registered.

RESULTS

Women randomized to metformin gained less weight during pregnancy compared with those in the placebo group. In the newborns, there was no difference between the 2 groups in weight or length. One year postpartum, women who used metformin in pregnancy lost less weight and their infants were heavier than those in the placebo group (10.2 ± 1.2 kg vs 9.7 ± 1.1 kg, P = .003).

CONCLUSIONS

Women randomized to metformin were heavier in the first trimester, gained less weight in pregnancy, and lost less weight in the first year postpartum compared with women randomized to placebo. Children exposed to metformin weighed more at 1 year of age.

Growth, body composition and metabolic profile of 8-year-old children exposed to metformin in utero

OBJECTIVES

To investigate the possible long-term effects of metformin exposure on growth and development of the offspring born to mothers with polycystic ovary syndrome (PCOS). The drug passes through the placenta and can potentially influence the fetus.

PATIENTS AND METHODS

This is a follow-up study of a randomized, controlled trial on PCOS women, randomized to metformin or placebo in pregnancy. Out of 37 children aged 7-9 years, 25 agreed to participate. Primary outcome measures were growth, body composition and metabolic parameters.

RESULTS

There were no differences in height, weight or body composition between those exposed to metformin and those exposed to placebo. We found a higher fasting glucose level in the metformin group (4.93 mmol/L vs. 4.60 mmol/L, p = 0.04). In the metformin group there was a trend towards higher systolic blood pressure (106 mmHg vs. 101 mmHg, p = 0.05) and a lower LDL cholesterol level (2.42 mmol/L vs. 2.99 mmol/L, p = 0.07).

CONCLUSION

Metformin exposure during fetal life does not seem to influence growth and body composition at the age of 8 years. A higher fasting glucose level and a possible higher systolic blood pressure and lower LDL cholesterol level in the metformin group may be coincidental and should be further explored.

Gestational Diabetes and the Offspring: Implications in the Development of the Cardiorenal Metabolic Syndrome in Offspring

The risk of developing type 2 diabetes and cardiovascular disease in women who had previously been diagnosed with gestational diabetes (GDM) is well established. There is increasing evidence that the offspring of women with GDM are at increased risk for the development of all components of the cardiorenal metabolic syndrome. Overall, it appears that these offspring have an increased risk for overweight/obesity, insulin resistance, higher blood pressure, renal disease, and type 2 diabetes. However, distinct differences in regional populations, lack of routine screening and treatment of GDM worldwide, and long follow-up periods for offspring represent a challenge in assessing the risk for development of these abnormalities in the offspring of women who have had GDM.

Gestational diabetes: screening for all, which test and which treatment?

Gestational diabetes mellitus is rapidly increasing in incidence, due to lifestyle changes, increasing obesity and maternal age. This increase makes universal screening mandatory; however, we are still far from it. Moreover, should we adopt rather strict oral glucose tolerance test cutoff values, resulting in a worldwide incidence of gestational diabetes mellitus of approximately 17.5%, or should we be more liberal and focus more on patients and offspring at increased risk, for example, obese women. Finally, are oral antidiabetic drugs such as glyburide and metformin safe enough to use in gestational diabetes mellitus, or should they still be considered as the 'poor man's insulin'? These issues were presented and discussed during lively debates at the Controversies in Obstetrics, Gynecology and Infertility annual meetings, but consensus was not reached.