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

Pharmacological Management of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common morbidities complicating pregnancy, with short- and long-term consequences to the mothers, fetuses, and newborns. Management and treatment are aimed to achieve best possible glycemic control, while avoiding hypoglycemia and ensuring maternal and fetal safety. It involves behavioral modifications, nutrition and medications, if needed; concurrent with maternal and fetal surveillance for possible adverse outcomes. This review aims to elaborate on the pharmacological options for GDM therapy. We performed an extensive literature review of different available studies, published during the last 50 years, concerning pharmacological therapy for GDM, dealing with safety and efficacy, for both fetal and maternal morbidity consequences; as well as failure and success in establishing appropriate metabolic and glucose control. Oral medication therapy is a safe and effective treatment modality for GDM and in some circumstances may serve as first-line therapy when nutritional modifications fail. When oral agents fail to establish glucose control then insulin injections should be added. Determining the best oral therapy in inconclusive, although it seems that metformin is slightly superior to glyburide, in some aspects. As for parenteral therapy, all insulins listed in this article are considered both safe and effective for treatment of hyperglycemia during pregnancy. Importantly, a better safety profile, with similar efficacy is documented for most analogues. As GDM prevalence rises, there is a need for successful monitoring and treatment for patients. Caregivers should know the possible and available therapeutic options.

Neurodevelopmental outcome at 2 years in offspring of women randomised to metformin or insulin treatment for gestational diabetes

OBJECTIVE

Gestational diabetes mellitus (GDM) is a common complication of pregnancy and is increasingly being treated with metformin that crosses the placenta rather than insulin, which does not. This study seeks to examine the neurodevelopment of offspring of women treated with metformin or insulin for GDM.

DESIGN

We performed a prospective follow-up study of children whose mothers had been randomly assigned at 20-33 weeks gestation to treatment with metformin or insulin for GDM. Of the 211 children followed up at 2 years, 128 were from Auckland, New Zealand (64 metformin vs 64 insulin), and 83 from Adelaide, Australia (39 metformin vs 49 insulin). Neurodevelopment was examined with the Bayley Scales of Infant Development V.2 mental development index (MDI) and psychomotor development index (PDI). Clinical and demographic background characteristics were obtained at enrolment, birth and follow-up.

RESULTS

No significant differences were found between treatment groups in clinical or demographic characteristics. The MDI and PDI composite scores were tested with general linear models. No significant differences were found between metformin and insulin, respectively, in New Zealand (MDI, M=83.6 vs 86.9 and PDI, M=83.4 vs M=85.2) or Australia (MDI, M=102.5 vs M=98.4 and PDI, M=105.6 vs M=99.9) and no interactions observed. The differences in neurodevelopmental outcomes between the Auckland and Adelaide cohorts were explained by parental ethnicity, infant birth weight >4000 g, neonatal hypoglycaemia, maternal glycaemia and smoking in the household.

CONCLUSIONS

This study provides additional data supporting the safety of metformin in the treatment of GDM.

TRIAL REGISTRATION NUMBER

ACTRN 12605000311651.

Neuropeptide Y Overexpressing Female and Male Mice Show Divergent Metabolic but Not Gut Microbial Responses to Prenatal Metformin Exposure

Background

Prenatal metformin exposure has been shown to improve the metabolic outcome in the offspring of high fat diet fed dams. However, if this is evident also in a genetic model of obesity and whether gut microbiota has a role, is not known.

Methods

The metabolic effects of prenatal metformin exposure were investigated in a genetic model of obesity, mice overexpressing neuropeptide Y in the sympathetic nervous system and in brain noradrenergic neurons (OE-NPY^DβH). Metformin was given for 18 days to the mated female mice. Body weight, body composition, glucose tolerance and serum parameters of the offspring were investigated on regular diet from weaning and sequentially on western diet (at the age of 5–7 months). Gut microbiota composition was analysed by 16S rRNA sequencing at 10–11 weeks.

Results

In the male offspring, metformin exposure inhibited weight gain. Moreover, weight of white fat depots and serum insulin and lipids tended to be lower at 7 months. In contrast, in the female offspring, metformin exposure impaired glucose tolerance at 3 months, and subsequently increased body weight gain, fat mass and serum cholesterol. In the gut microbiota, a decline in Erysipelotrichaceae and Odoribacter was detected in the metformin exposed offspring. Furthermore, the abundance of Sutterella tended to be decreased and Parabacteroides increased. Gut microbiota composition of the metformin exposed male offspring correlated to their metabolic phenotype.

Conclusion

Prenatal metformin exposure caused divergent metabolic phenotypes in the female and male offspring. Nevertheless, gut microbiota of metformin exposed offspring was similarly modified in both genders.

Current Therapies for the Medical Management of Diabetes

Diabetes affects a large and diverse number of individuals who share in common its risks for complications but who differ greatly from one another in age, health, and a number of circumstances influential to successful treatment. Because type 2 diabetes comprises the majority of diabetes cases, a number of agents have been developed for its treatment. Their unique properties offer opportunities to overcome some of the treatment limitations of older medicines and enable a more individualized and flexible approach to glucose-lowering. At the same time, new medications are accompanied by greater costs and uncertainties about their long-term benefits or safety, and thus the present state of care for type 2 diabetes places focus on a process of shared decision-making between the clinician and patient as to which treatments can optimize health while minimizing harms. We review the major classes of diabetes agents and provide some guidance for how one might approach decision-making in choosing among them.

Metformin in women with type 2 diabetes in pregnancy (MiTy): a multi-center randomized controlled trial

Background

The incidence of type 2 diabetes in pregnancy is rising and rates of serious adverse maternal and fetal outcomes remain high. Metformin is a biguanide that is used as first-line treatment for non-pregnant patients with type 2 diabetes. We hypothesize that metformin use in pregnancy, as an adjunct to insulin, will decrease adverse outcomes by reducing maternal hyperglycemia, maternal insulin doses, maternal weight gain and gestational hypertension/pre-eclampsia. In addition, since metformin crosses the placenta, metformin treatment of the fetus may have a direct beneficial effect on neonatal outcomes. Our aim is to compare the effectiveness of the addition of metformin to insulin, to standard care (insulin plus placebo) in women with type 2 diabetes in pregnancy.

Methods

The MiTy trial is a multi-centre randomized trial currently enrolling pregnant women with type 2 diabetes, who are on insulin, between the ages of 18–45, with a gestational age of 6 weeks 0 days to 22 weeks 6 days. In this randomized, double-masked, parallel placebo-controlled trial, after giving informed consent, women are randomized to receive either metformin 1,000 mg twice daily or placebo twice daily. A web-based block randomization system is used to assign women to metformin or placebo in a 1:1 ratio, stratified for site and body mass index. The primary outcome is a composite neonatal outcome of pregnancy loss, preterm birth, birth injury, moderate/severe respiratory distress, neonatal hypoglycemia, or neonatal intensive care unit admission longer than 24 h. Secondary outcomes are large for gestational age, cord blood gas pH < 7.0, congenital anomalies, hyperbilirubinemia, sepsis, hyperinsulinemia, shoulder dystocia, fetal fat mass, as well as maternal outcomes: maternal weight gain, maternal insulin doses, maternal glycemic control, maternal hypoglycemia, gestational hypertension, preeclampsia, cesarean section, number of hospitalizations during pregnancy, and duration of hospital stays. The trial aims to enroll 500 participants.

Discussion

The results of this trial will inform endocrinologists, obstetricians, family doctors, and other healthcare professionals caring for women with type 2 diabetes in pregnancy, as to the benefits of adding metformin to insulin in this high risk population.

Trial registration

ClinicalTrials.gov Identifier: no. NCT01353391. Registered February 6, 2009.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-0954-4) contains supplementary material, which is available to authorized users.

Is it worth treating gestational diabetes: if so, when and how?

The primary aims of the treatment of gestational diabetes (GDM) are to prevent macrosomia and pregnancy complications. Many large studies and meta-analyses have demonstrated that, compared with usual care, the specific treatment of women with GDM seems to achieve these aims, including lower birthweight and lower rates of shoulder dystocia. Nutritional therapy is a cornerstone of GDM care and is generally recommended as a primary treatment. Medical treatment should be started after 1-2 weeks if normoglycaemia is not achieved with lifestyle changes. This review provides an overview of the current data on and practices for the treatment of GDM and summarises a presentation given at the 'Gestational diabetes: what's up?' symposium at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Peter Damm and Colleagues, DOI: 10.1007/s00125-016-3985-5 , and by Cuilin Zhang and colleagues, DOI: 10.1007/s00125-016-3979-3 ) and an overview by the Session Chair, Kerstin Berntorp (DOI: 10.1007/s00125-016-3975-7 ).

Antenatal dietary and lifestyle advice for women who are overweight or obese and the effect on fetal growth and adiposity: the LIMIT randomised trial

OBJECTIVE

To report the influence of maternal overweight and obesity on fetal growth and adiposity and effects of an antenatal dietary and lifestyle intervention among these women on measures of fetal growth and adiposity as secondary outcomes of the LIMIT Trial.

DESIGN

Randomised controlled trial.

SETTING

Public maternity hospitals in metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with a body mass index ≥ 25 kg/m(2), and singleton gestation between 10(+0) and 20(+0) weeks.

METHODS

Women were randomised to Lifestyle Advice or continued Standard Care and offered two research ultrasound scans at 28 and 36 weeks of gestation.

MAIN OUTCOME MEASURES

Ultrasound measures of fetal growth and adiposity.

RESULTS

For each fetal body composition parameter, mean Z-scores were substantially higher when compared with population standards. Fetuses of women receiving Lifestyle Advice demonstrated significantly greater mean mid-thigh fat mass, when compared with fetuses of women receiving Standard Care (adjusted difference in means 0.17; 95% CI 0.02-0.32; P = 0.0245). While subscapular fat mass increased between 28 and 36 weeks of gestation in fetuses in both treatment groups, the rate of adipose tissue deposition slowed among fetuses of women receiving Lifestyle Advice, when compared with fetuses of women receiving Standard Care (P = 0.0160). No other significant differences were observed.

CONCLUSIONS

These findings provide the first evidence of changes to fetal growth following an antenatal dietary and lifestyle intervention among women who are overweight or obese.

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. 

Metformin versus insulin in gestational diabetes mellitus: a meta-analysis of randomized clinical trials

BACKGROUND

Metformin is widely used in treatment of type 2 diabetes. However, whether it is safe for use in pregnancy is controversial.

METHODS

A search for relevant studies were performed using PubMed (1948-2014), Embase (1974-2014), the Web of knowledge (1950-2014), and the Cochrane database, included all randomized control trials published in English.

RESULTS

Eight RCTs (1712 patients with gestational diabetes mellitus) were retrieved; of those 853 patients were given metformin, and 859 patients were given insulin. Our results showed that metformin does not increase risk of prematurity (RR = 1.26; 95 % CI [0.89, 1.79], P = 0.19). In addition, metformin can either decrease the total weight gain [MD = -1.49, 95 % CI (-2.66, -0.31), P = 0.01] or weight gain after randomization [MD = -1.23, 95 % CI (-1.75, -0.71), P < 0.00001]. No significant differences were observed in patients with pre-eclampsia [RR = 0.82, 95 % CI (0.56, 1.2), P = 0.32] or caesarean section [RR = 0.93, 95 % CI (0.75, 1.16), P = 0.53]. Use of metformin also significantly decreased the risk of neonatal hypoglycemia [RR = 0.58, 95 % CI (0.43, 0.78), P = 0.0003] and admission rates to neonatal intensive care units [RR = 0.74, 95 % CI (0.61, 0.89), P = 0.002]. No other adverse effects were observed, such as hyperbilirubinaemia [RR = 0.83, 95 % CI (0.64, 1.08), P = 0.16], large for gestational age [RR = 0.85, 95 % CI (0.68, 1.05), P = 0.14], small for gestational age [RR = 0.92, 95 % CI (0.61, 1.39), P = 0.69], macrosomia [RR = 0.75, 95 % CI (0.54, 1.03), P = 0.07] or respiratory distress syndrome [RR = 0.88, 95 % CI (0.55, 1.41), P = 0.6].

CONCLUSIONS

Metformin may be beneficial in treating gestational diabetes. However, even more studies are needed to provide more evidence for the future use of metformin.

ENDOCRINOLOGY OF PREGNANCY: Gestational diabetes mellitus: definition, aetiological and clinical aspects

Gestational diabetes (GDM) is defined as a glucose intolerance resulting in hyperglycaemia of variable severity with onset during pregnancy. This review aims to revisit the pathogenesis and aetiology of GDM in order to better understand its clinical presentation and outcomes. During normal pregnancy, insulin sensitivity declines with advancing gestation. These modifications are due to placental factors, progesterone and estrogen. In a physiological situation, a compensatory increase in insulin secretion maintains a normal glucose homeostasis. GDM occurs if pancreatic β-cells are unable to face the increased insulin demand during pregnancy. GDM is most commonly a forerunner of type 2 diabetes (T2D) - the most prevalent form of diabetes. These women share similar characteristics with predisposed subjects to T2D: insulin resistance before and after pregnancy, and carry more T2D risk alleles. Auto-immune and monogenic diabetes are more rare aetiologies of GDM. Adverse pregnancy outcomes of GDM are mainly related to macrosomia caused by fetal hyperinsulinism in response to high glucose levels coming from maternal hyperglycaemia. Screening recommendations and diagnosis criteria of GDM have been recently updated. High risk patients should be screened as early as possible using fasting plasma glucose, and if normal, at 24-28 weeks of gestation using 75 g oral glucose tolerance test. The treatment of GDM is based on education with trained nurses and dieticians, and if necessary insulin therapy.

Metformin Treatment Does Not Affect Testicular Size in Offspring Born to Mothers with Gestational Diabetes

OBJECTIVES

Studies in rodents suggest that metformin treatment during pregnancy may have harmful effects on testicular development in offspring. Our aim was to determine whether metformin treatment of gestational diabetes mellitus (GDM) affects testicular size in male offspring.

METHODS

We compared the testicular size in prepubertal boys born to mothers who participated in a randomized controlled trial (RCT) comparing metformin with insulin in the treatment of GDM. Twenty-five (42.4% of invited) and 27 (52.9% of invited) boys whose mothers had been treated with metformin or insulin, respectively, participated in the study. Testicular size was measured by a ruler, an orchidometer, and by ultrasonography at the age of 33 to 85 months.

RESULTS

The mean age of the boys was 60 months at the time of examination, and did not differ between the metformin and insulin group (p = 0.88). There was no difference in testicular size between the boys in the two groups (p always ≥ 0.40), and there were no significant differences in height, weight, BMI, BMI z-score, or waist-to-hip ratio (WHR) between the boys in the groups.

CONCLUSIONS

Prepubertal testicular size did not differ between offspring born to metformin-treated mothers and those born to insulin-treated mothers.

Neurodevelopment of Two-Year-Old Children Exposed to Metformin and Insulin in Gestational Diabetes Mellitus

OBJECTIVE

To compare cognitive, language, and motor skills and results of neurological examination in 2-year-old children born to mothers with gestational diabetes mellitus treated with metformin with those treated with insulin.

METHOD

The children of mothers with gestational diabetes mellitus randomized to metformin (n = 75) or insulin (n = 71) treatment during pregnancy were examined by standardized developmental and neurological measures; the Bayley Scales of Infant and Toddler Development (Bayley-III) and the Hammersmith Infant Neurological Examination.

RESULTS

There were no significant differences between the metformin and insulin groups in the Bayley Scales of Infant and Toddler Development (Bayley-III) test of cognitive scale (p = .12), receptive communication (p = .14) or expressive communication (p = .75), fine motor scale (p = .10) or gross motor scale (p = .13), or the global scores of Hammersmith Infant Neurological Examination (p = .14). None of the children had a clinically significant developmental problem. However, compared with age-adjusted norms, a trend for weaker language performance was observed in both study groups.

CONCLUSION

No differences in neurodevelopmental outcome were seen in 2-year-old children born to mothers with gestational diabetes mellitus (GDM) treated with insulin or metformin during pregnancy. The results suggest that children born to mothers with GDM and exposed to metformin in utero do not systematically need extensive formal neurodevelopmental assessment in early childhood.

American Indian Diabetes Beliefs and Practices: Anxiety, Fear, and Dread in Pregnant Women With Diabetes

Diabetes among American Indian (AI) people is a health disparities condition that creates excessive morbidity and mortality. This research delineated culturally constructed models of type 2 diabetes among 97 pregnant women in two large AI nations in Oklahoma. The data analysis of explanatory models of type 2 diabetes revealed the participants' intense anxiety, fear, and dread related to the condition. The sample was further stratified by combinations of diabetes status: 1) absence of type 2 diabetes (n = 66), 2) type 2 diabetes prior to pregnancy (n = 4), and 3) gestational diabetes (n = 27). Patients were interviewed regarding perceptions of the etiology, course, and treatment of diabetes. The research incorporated an integrated phenomenologic and ethnographic approach using structured and semi-structured interviews to yield both quantitative and qualitative data. General findings comprised three main categories of patients' concerns regarding type 2 diabetes as an illness: 1) mechanical acts (i.e., injections), 2) medical complications, and 3) the conceptual sense of diabetes as a "severe" condition. Specific findings included significant fear and anxiety surrounding 1) the health and well-being of the unborn child, 2) the use of insulin injections, 3) blindness, 4) amputation, and 5) death. Paradoxically, although there was only a slight sense of disease severity overall, responses were punctuated with dread of specific outcomes. The latter finding is considered consistent with the presence of chronic diseases that can usually be managed but present risk of severe complications if not well controlled.

Influence of maternal overnutrition and gestational diabetes on the programming of metabolic health outcomes in the offspring: experimental evidence

The incidence of obesity and type 2 diabetes mellitus have risen across the world during the past few decades and has also reached an alarming level among children. In addition, women are currently more likely than ever to enter pregnancy obese. As a result, the incidence of gestational diabetes mellitus is also on the rise. While diet and lifestyle contribute to these trends, population health data show that maternal obesity and diabetes during pregnancy during critical stages of development are major factors that contribute to the development of chronic disease in adolescent and adult offspring. Fetal programming of metabolic function, through physiological and (or) epigenetic mechanisms, may also have an intergenerational effect, and as a result may perpetuate metabolic disorders in the next generation. In this review, we summarize the existing literature that characterizes how maternal obesity and gestational diabetes mellitus contribute to metabolic and cardiovascular disorders in the offspring. In particular, we focus on animal studies that investigate the molecular mechanisms that are programmed by the gestational environment and lead to disease phenotypes in the offspring. We also review interventional studies that prevent disease with a developmental origin in the offspring.

Safety considerations with pharmacological treatment of gestational diabetes mellitus

The number of women with gestational diabetes mellitus (GDM: diabetes first diagnosed in pregnancy) continues to grow, as do the associated risks of antenatal and postnatal complications and the chance of future diabetes and obesity in both mother and offspring. Recent randomised controlled trials have demonstrated clear benefits for intensive management of GDM using lifestyle modification, self blood glucose monitoring, close clinical supervision and, where glycaemia remains inadequately controlled, insulin therapy. More recently, metformin and glibenclamide have been shown to adequately reduce hyperglycaemia as part of a stepped approach to GDM management, with a switch to insulin therapy where necessary. Other oral medications have not been shown to be safe in pregnancy. Human insulin therapy is safe within the limits of hypoglycaemia and weight gain. Most insulin analogues are also now considered safe for use in pregnancy (insulin lispro, aspart and detemir). Metformin therapy is oral, and therefore preferred to insulin, but is associated with more gastrointestinal adverse effects, although not hypoglycaemia or weight gain. Conversely, glibenclamide is also an oral therapy but is associated with hypoglycaemia and weight gain. However, metformin crosses the placenta and it remains unclear whether glibenclamide crosses the placenta or not: long-term risks have not been shown, and are thought to be minimal, but further studies are needed. Metformin is seen by some as the treatment of choice where weight gain is an issue, providing that the unanswered questions over the long-term safety of oral agents have been discussed.

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

The aim of the present meta-analysis was to determine the efficacy and safety of metformin for the treatment of women with gestational diabetes mellitus (GDM). We searched databases, including PubMed, Embase and the Cochrane Central Register of Controlled Trials, for randomized controlled trials (RCTs) comparing metformin and insulin treatments in women with GDM. We carried out statistical analyses using RevMan 2011 and used the Grading of Recommendations, Assessment, Development, and Evaluations profiler to rate the quality of evidence of the primary outcomes. We analysed eight studies involving 1592 subjects. Meta-analysis of the RCTs showed that metformin had statistically significant effects on pregnancy-induced hypertension [PIH; risk ratio (RR) 0.54; 95% confidence interval (CI) 0.31, 0.91]. However, its effects on neonatal hypoglycaemia (RR 0.80; 95% CI 0.62, 1.02), rate of large-for-gestational age infants (RR 0.77; 95% CI 0.55, 1.08), respiratory distress syndrome (RR 1.26; 95% CI 0.67, 2.37), phototherapy (RR 0.94; 95% CI 0.67, 1.31) and perinatal death (RR 1.01; 95% CI 0.11, 9.53) were not significant. Our analyses suggest that there is no clinically relevant difference in efficacy or safety between metformin and insulin; however, metformin may be a good choice for GDM because of the lower risk of PIH. The advantages of metformin in terms of glycaemic control, PIH incidence and gestational age at birth are unclear, and should be verified in further trials.

Blood pressure measurement at two years in offspring of women randomized to a trial of metformin for GDM: follow up data from the MiG trial

Background

Offspring born following maternal gestational diabetes are at risk of excessive childhood weight gain and Type 2 diabetes in childhood, which in turn is associated with an increased rate of hypertension.

We aimed to determine the systolic and diastolic blood pressure at two years of age in a cohort of children exposed to gestational diabetes mellitus using data from the MiG trial of metformin use in gestational diabetes. The secondary aim was to analyze these data by randomization of treatment to insulin or metformin.

Methods

The offspring of women who had gestational diabetes and had been assigned to either open treatment with metformin (with supplemental insulin if required) or insulin in the MiG trial were followed up at 2 years of age. Oscillometric measurement of BP in the right arm was performed by a researcher using an appropriately sized cuff.

Results

A total of 489 measurement blood pressure measurements were obtained in 170 of the 222 children who were seen at a median (range) age of 29 (22–38) months corrected gestational age. At the time of assessment the mean (SD) weight and height was 13.8(2) kg and 90 (4.2) cm respectively. For the whole group the mean (SD) systolic pressure was 90.9 (9.9) mmHg and mean (SD) diastolic pressure was 55.7 (8.1) mmHg. No difference was found between the metformin and insulin treatment arms. In a regression model, height and weight were only two factors associated with the levels of systolic blood pressure. For each additional kg the systolic blood pressure increased by 1.0 mmHg. For each additional cm of height the systolic blood pressure increased by 0.42 mmHg.

Conclusions

Blood pressure data was obtained at approximately two years of age in a substantial cohort of children whose mothers received treatment for GDM. These novel data compare favorably with published norms.

Clinical Trials Registry

This study was registered under the Australian New Zealand Clinical Trials Registry (ACTRN12605000311651).

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

AIM

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Endoplasmic reticulum stress is increased in adipose tissue of women with gestational diabetes

Maternal obesity and gestational diabetes mellitus (GDM) are two increasingly common and important obstetric complications that are associated with severe long-term health risks to mothers and babies. IL-1β, which is increased in obese and GDM pregnancies, plays an important role in the pathophysiology of these two pregnancy complications. In non-pregnant tissues, endoplasmic (ER) stress is increased in diabetes and can induce IL-1β via inflammasome activation. The aim of this study was to determine whether ER stress is increased in omental adipose tissue of women with GDM, and if ER stress can also upregulate inflammasome-dependent secretion of IL-1β. ER stress markers IRE1α, GRP78 and XBP-1s were significantly increased in adipose tissue of obese compared to lean pregnant women. ER stress was also increased in adipose tissue of women with GDM compared to BMI-matched normal glucose tolerant (NGT) women. Thapsigargin, an ER stress activator, induced upregulated secretion of mature IL-1α and IL-1β in human omental adipose tissue explants primed with bacterial endotoxin LPS, the viral dsRNA analogue poly(I:C) or the pro-inflammatory cytokine TNF-α. Inhibition of capase-1 with Ac-YVAD-CHO resulted in decreased IL-1α and IL-1β secretion, whereas inhibition of pannexin-1 with carbenoxolone suppressed IL-1β secretion only. Treatment with anti-diabetic drugs metformin and glibenclamide also reduced IL-1α and IL-1β secretion in infection and cytokine-primed adipose tissue. In conclusion, this study has demonstrated ER stress to activate the inflammasome in pregnant adipose tissue. Therefore, increased ER stress may contribute towards the pathophysiology of obesity in pregnancy and GDM.

Changing trends in management of gestational diabetes mellitus

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

Metformin in gestational diabetes: An emerging contender

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

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

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

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

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

Using oral agents to manage gestational diabetes: what have we learned?

Insulin has been the mainstay of treatment of diabetes during pregnancy for decades. Although glyburide and metformin are classified as category B during pregnancy, recent research has suggested that these oral agents alone or in conjunction with insulin may be safe for the treatment of gestational diabetes (GDM). This paper summarizes the data on the use of glyburide and metformin for treatment of GDM.

Efficacy of metformin in pregnant obese women: a randomised controlled trial

INTRODUCTION

Increasing evidence suggests obesity has its origins prior to birth. There is clear correlation between maternal obesity, high birthweight and offspring risk of obesity in later life. It is also clear that women who are obese during pregnancy are at greater risk of adverse outcomes, including gestational diabetes and stillbirth. The mechanism(s) by which obesity causes these problems is unknown, although hyperglycaemia and insulin resistance are strongly implicated. We present a protocol for a study to test the hypothesis that metformin will improve insulin sensitivity in obese pregnant women, thereby reducing the incidence of high birthweight babies and other pregnancy complications.

METHODS AND ANALYSIS

The Efficacy of Metformin in Pregnant Obese Women, a Randomised controlled (EMPOWaR) trial is a double-masked randomised placebo-controlled trial to determine whether metformin given to obese (body mass index >30 kg/m(2)) pregnant women from 16 weeks' gestation until delivery reduces the incidence of high birthweight babies. A secondary aim is to test the mechanism(s) of any effect. Obese women with a singleton pregnancy and normal glucose tolerance will be recruited prior to 16 weeks' gestation and prescribed study medication, metformin or placebo, to be taken until delivery. Further study visits will occur at 28 and 36 weeks' gestation for glucose tolerance testing and to record anthropometric measurements. Birth weight and other measurements will be recorded at time of delivery. Anthropometry of mother and baby will be performed at 3 months postdelivery. As of January 2014, 449 women had been randomised across the UK.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the principles of Good Clinical Practice. A favourable ethical opinion was obtained from Scotland A Research Ethics Committee, reference number 10/MRE00/12. Results will be disseminated at conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN51279843.

Prenatal metformin exposure in a maternal high fat diet mouse model alters the transcriptome and modifies the metabolic responses of the offspring

AIMS

Despite the wide use of metformin in metabolically challenged pregnancies, the long-term effects on the metabolism of the offspring are not known. We studied the long-term effects of prenatal metformin exposure during metabolically challenged pregnancy in mice.

MATERIALS AND METHODS

Female mice were on a high fat diet (HFD) prior to and during the gestation. Metformin was administered during gestation from E0.5 to E17.5. Male and female offspring were weaned to a regular diet (RD) and subjected to HFD at adulthood (10-11 weeks). Body weight and several metabolic parameters (e.g. body composition and glucose tolerance) were measured during the study. Microarray and subsequent pathway analyses on the liver and subcutaneous adipose tissue of the male offspring were performed at postnatal day 4 in a separate experiment.

RESULTS

Prenatal metformin exposure changed the offspring's response to HFD. Metformin exposed offspring gained less body weight and adipose tissue during the HFD phase. Additionally, prenatal metformin exposure prevented HFD-induced impairment in glucose tolerance. Microarray and annotation analyses revealed metformin-induced changes in several metabolic pathways from which electron transport chain (ETC) was prominently affected both in the neonatal liver and adipose tissue.

CONCLUSION

This study shows the beneficial effects of prenatal metformin exposure on the offspring's glucose tolerance and fat mass accumulation during HFD. The transcriptome data obtained at neonatal age indicates major effects on the genes involved in mitochondrial ATP production and adipocyte differentiation suggesting the mechanistic routes to improved metabolic phenotype at adulthood.

Impact of metformin on reproductive tissues: an overview from gametogenesis to gestation

Metformin is an oral anti-hyperglycemic drug that acts as an insulin sensitizer in the treatment of diabetes mellitus type 2. It has also been widely used in the treatment of polycystic ovary syndrome (PCOS) and gestational diabetes. This drug has been shown to activate a protein kinase called 5' AMP-activated protein kinase or AMPK. AMPK is present in many tissues making metformin's effect multi factorial. However as metformin crosses the placenta, its use during pregnancy raises concerns regarding potential adverse effects on the mother and fetus. The majority of reports suggest no significant adverse effects or teratogenicity. However, disconcerting reports of male mouse offspring that were exposed to metformin in utero that present with a reduction in testis size, seminiferous tubule size and in Sertoli cell number suggest that we do not understand the full suite of effects of metformin. In addition, recent molecular evidence is suggesting an epigenetic effect of metformin which could explain some of the long-term effects reported. Nevertheless, the data are still insufficient to completely confirm or disprove negative effects of metformin. The aims of this review are to provide a summary of the safety of metformin in various aspects of sexual reproduction, the use of metformin by gestating mothers, and its possible side-effects on offspring from women who are administered metformin during pregnancy.

Dietary and lifestyle advice for pregnant women who are overweight or obese: the LIMIT randomized trial

Overweight and obesity during pregnancy are common and are associated with an increased risk of adverse health outcomes for both the mother and the infant. However, robust evidence about the effect of antenatal dietary and lifestyle interventions on health outcomes is lacking. We conducted a multicenter, randomized trial, recruiting 2,212 women (from 3 public maternity hospitals across South Australia) with a singleton pregnancy between 10⁺⁰ and 20⁺⁰ weeks' gestation and a BMI ≥25. The women were randomized to lifestyle advice (n = 1,108) or standard care (n = 1,104). Women randomized to lifestyle advice participated in a comprehensive dietary and lifestyle intervention over the course of their pregnancy (delivered by research staff), while women randomized to standard care received pregnancy care according to local guidelines, which did not include such information. Provision of the lifestyle intervention was associated with a significant 18% relative risk reduction in the chance of infants being born with a birth weight above 4 kg. No other significant differences were identified in maternal pregnancy and birth outcomes between the two treatment groups. Observational studies highlight the association between a high infant birth weight and the subsequent risk of childhood and adulthood obesity. Antenatal interventions that are effective in reducing high infant birth weights therefore represent a significant strategy to tackle obesity from a population health perspective, while ongoing interrogation of the biospecimens and measurements, including ongoing childhood follow-up, will provide a unique opportunity to evaluate the mechanistic pathways of maternal-to-infant/childhood obesity.

Body composition in offspring of New Zealand women: ethnic and gender differences at age 1-3 years in 2005-2009

BACKGROUND

In multi-ethnic New Zealand the prevalence of obesity and diabetes is increasing and varies by ethnic group.

AIM

This study explored ethnic and gender differences in body composition in offspring of women treated for gestational diabetes in the metformin in gestational diabetes (MiG) trial.

SAMPLE AND METHODS

Total and regional body composition measured by dual X-ray absorptiometry were investigated in European, Indian, Polynesian and "Other" children aged 2 years (48 boys; 56 girls).

RESULTS

By ethnicity, boys were not different by height or weight. Compared with European girls, Indian girls weighed less (2.3 ± 0.58 kg) and Polynesian (1.13 ± 0.53 kg) more, but percentage body fat was not different. Adjusted for age, height and weight boys had less total and appendicular fat and higher abdominal fat mass and total bone mineral density than girls (p < 0.001). Adjusted for age, weight and height Indian boys had more fat in the central and abdominal regions and less total lean mass than European boys (p < 0.05).

CONCLUSION

These measurements provide early evidence for gender and ethnic differences in the distribution of fat and might help identify who is most likely to benefit from intervention in the first few years of life to reduce risk of chronic disease including diabetes.

Unresolved controversies in gestational diabetes: implications on maternal and infant health

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is a major public health concern because of rising rates and offspring consequences; yet, expert panels are in complete disagreement on how to diagnose and optimally treat GDM. This review underscores why there remains no diagnostic standard, no agreement on whether excess dietary carbohydrate or fat should be reduced, and whether oral hypoglycemic therapy is safe given the unknown offspring effects on hepatic, pancreatic, or fat development.

RECENT FINDINGS

New diagnostic criteria proposed by the American Diabetes Association would triple the prevalence of GDM (∼18%). Whether the treatment of women with these milder degrees of hyperglycemia will improve pregnancy outcomes is unknown given the powerful effect of obesity alone on excess fetal growth. There are data that restricting carbohydrate in the diet by substituting fat to blunt postprandial glucose levels may worsen maternal insulin resistance and that metformin may increase offspring subcutaneous fat.

SUMMARY

The adoption of the new American Diabetes Association diagnostic criteria for GDM was rejected by ACOG and not endorsed by the NIH. Yet, varying criteria are used by different centers resulting in confusion for both patient care and research. Both maternal diet and agents that cross the placenta could potentially modify offspring gene expression. Better identification and treatment of mothers and fetuses at risk may have far-reaching implications for maternal and child health.

The use of oral hypoglycaemic agents in pregnancy

While insulin has been the treatment of choice when lifestyle measures do not maintain glycaemic control during pregnancy, recent studies have suggested that certain oral hypoglycaemic agents may be safe and acceptable alternatives. With the exception of metformin and glibenclamide (glyburide), there are insufficient data to recommend treatment with any other oral hypoglycaemic agent during pregnancy. There are no serious safety concerns with metformin, despite it crossing the placenta. When used in the first trimester, there is no increase in congenital abnormalities and there appears to be a reduction in miscarriage, pre-eclampsia and subsequent gestational diabetes. Studies of the use of metformin in gestational diabetes show at least equivalent neonatal outcomes, while reporting reductions in neonatal hypoglycaemia, maternal hypoglycaemia and weight gain and improved treatment satisfaction. Glibenclamide effectively lowers blood glucose in women with gestational diabetes, possibly with a lower treatment failure rate than metformin. Although generally well tolerated, some studies have reported higher rates of pre-eclampsia, neonatal jaundice, longer stay in the neonatal care unit, macrosomia and neonatal hypoglycaemia. There is a paucity of long-term follow-up data on children exposed to oral agents in utero. The American College of Obstetrics and Gynecology and the UK National Institute of Health and Care Excellence (NICE) have recommended that either metformin or glibenclamide can be used to treat gestational diabetes. Metformin is also recommended for use in the pre-conception period by NICE. By contrast, the American Diabetes Association recommends that both drugs should only be used during pregnancy in the context of clinical trials.

Anthropometrics and body composition by dual energy X-ray in children of obese women: a follow-up of a randomized controlled trial (the Lifestyle in Pregnancy and Offspring [LiPO] study)

OBJECTIVE

In obese women, 1) to assess whether lower gestational weight gain (GWG) during pregnancy in the lifestyle intervention group of a randomized controlled trial (RCT) resulted in differences in offspring anthropometrics and body composition, and 2) to compare offspring outcomes to a reference group of children born to women with a normal Body Mass Index (BMI).

RESEARCH DESIGN AND METHODS

The LiPO (Lifestyle in Pregnancy and Offspring) study was an offspring follow-up of a RCT with 360 obese pregnant women with a lifestyle intervention during pregnancy including dietary advice, coaching and exercise. The trial was completed by 301 women who were eligible for follow-up. In addition, to the children from the RCT, a group of children born to women with a normal BMI were included as a reference group. At 2.8 (range 2.5-3.2) years, anthropometrics were measured in 157 children of the RCT mothers and in 97 reference group children with Body Mass Index (BMI) Z-score as a primary outcome. Body composition was estimated by Dual Energy X-ray (DEXA) in 123 successful scans out of 147 (84%).

RESULTS

No differences between randomized groups were seen in mean (95% C.I.) BMI Z-score (intervention group 0.06 [-0.17; 0.29] vs. controls -0.18 [-0.43; 0.05]), in the percentage of overweight or obese children (10.9% vs. 6.7%), in other anthropometrics, or in body composition values by DEXA. Outcomes between children from the RCT and the reference group children were not significantly different.

CONCLUSIONS

The RCT with lifestyle intervention in obese pregnant women did not result in any detectable effect on offspring anthropometrics or body composition by DEXA at 2.8 years of age. This may reflect the limited difference in GWG between intervention and control groups. Offspring of obese mothers from the RCT were comparable to offspring of mothers with a normal BMI.

Effect of maternal gestational diabetes on the cardiovascular risk factor profile of infants at 1 year of age

BACKGROUND AND AIM

Offspring of women with gestational diabetes (GDM) exhibit an adverse cardiovascular risk factor profile by as early as age 5 years. Recently, maternal glycemia has been associated with epigenetic modification of genes on the fetal side of the placenta, including those encoding emerging risk factors (adiponectin, leptin), suggesting that vascular differences may emerge even earlier in life. Thus, we sought to evaluate cardiovascular risk factors and determinants thereof in 1-year-old infants of women with and without GDM.

METHODS AND RESULTS

Traditional (glucose, lipids) and emerging (C-reactive protein (CRP), adiponectin, leptin) risk factors were assessed in pregnancy in 104 women with (n = 36) and without GDM (n = 68), and at age 1-year in their offspring. In pregnancy, women with GDM had higher triglycerides (2.49 vs 2.10 mmol/L, p = 0.04) and CRP (5.3 vs 3.6 mg/L, p = 0.03), and lower adiponectin (7.3 vs 8.5 μg/mL, p = 0.04) than did their peers. At age 1-year, however, there were no differences in cardiovascular risk factors (including adiponectin) between the infants of women with and without GDM. Of note, maternal and infant adiponectin levels were associated in the non-GDM group (r = 0.39, p = 0.001) but not in the GDM group (r = 0.07, p = 0.67). Furthermore, on multiple linear regression analyses, maternal adiponectin emerged as an independent predictor of infant adiponectin in the non-GDM group only (beta = 776.1, p = 0.0065).

CONCLUSION

Infants of women with and without GDM have a similar cardiovascular risk factor profile at age 1-year. However, there are differences in their early-life determinants of adiponectin that may be relevant to the subsequent vascular risk of GDM offspring.

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

BACKGROUND

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

OBJECTIVE

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

RESULTS

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

CONCLUSIONS

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