Effects of in-utero exposure to oral hypoglycaemic drugs

Zebrafish AC50 modelling: (Q)SAR models to predict developmental toxicity in zebrafish embryo

Developmental toxicity refers to the occurrence of adverse effects on a developing organism as a consequence of exposure to hazardous chemicals. The assessment of developmental toxicity has become relevant to the safety assessment process of chemicals. The zebrafish embryo developmental toxicology assay is an emerging test used to screen the teratogenic potential of chemicals and it is proposed as a promising test to replace teratogenic assays with animals. Supported by the increased availability of data from this test, the developmental toxicity assay with zebrafish has become an interesting endpoint for the in silico modelling. The purpose of this study was to build up quantitative structure-activity relationship (QSAR) models. In this work, new in silico models for the evaluation of developmental toxicity were built using a well-defined set of data from the ToxCast^TM Phase I chemical library on the zebrafish embryo. Categorical and continuous QSAR models were built by gradient boosting machine learning and the Monte Carlo technique respectively, in accordance with Organization for Economic Co-operation and Development principles and their statistical quality was satisfactory. The classification model reached balanced accuracy 0.89 and Matthews correlation coefficient 0.77 on the test set. The regression model reached correlation coefficient R² 0.70 in external validation and leave-one-out cross-validated Q² 0.73 in internal validation.

A comparison of the anti-diabetic potential of d-ribose-l-cysteine with insulin, and oral hypoglycaemic agents on pregnant rats

Over 18% of pregnant women are affected by diabetes mellitus (DM) and Insulin has been the commonest drug used in its treatment. There are reports of noncompliance to insulin due to trypanophobia, with suggestions for the use of oral hypoglycaemic agents (OHAs). However, the opposing views about the benefits and risk of oral hypoglycaemic agents (OHAs) warrant a continuous search for an alternative regimen. Therefore, this study is aimed at comparing the antidiabetic effects of d-ribose-l-cysteine (riboceine) with vildagliptin, glibenclamide, metformin, glipizide and insulin in diabetes in pregnancy. Forty (40) female Sprague-Dawley (SD) rats were mated with twenty (20) male SD rats. Diabetes was induced by streptozotocin and the female SD rats were divided into 8 groups of five (5) rats each. The animals were administered either of the OHAs vildagliptin, glibenclamide, metformin, glipizide and riboceine for a period of 19 gestational days. The results showed that streptozotocin (STZ) significantly (p < 0.05) decreased the weights of the animals, increased malondialdehyde, blood glucose levels and altered reproductive hormones. These effects of STZ were better ameliorated in animals that received insulin and riboceine compared to the other OHAs. While progesterone levels were significantly (p < 0.05) higher in animals that received riboceine compared to insulin. Glibenclamide increased (p < 0.05) foetal weights compared to non-diabetic animals. In conclusion, glibenclamide may be a threat to mother`s life in the management of diabetes in pregnancy however, riboceine as well as vildagliptin, metformin and glipizide are effective oral hypoglycaemic agents which could serve as a potent adjuvant comparable to insulin in the management of diabetes during gestation.

Pharmacological treatment of gestational diabetes mellitus: point/counterpoint

Controversies persist over the most efficacious pharmacologic treatment for gestational diabetes mellitus. For purposes of accuracy in this article, the individual American College of Obstetricians and Gynecologists Practice Bulletin and American Diabetes Association Standards of Medical Care positions on each issue are quoted and then deliberated with evidence of counter claims presented in point/counterpoint. This is a review of all the relevant evidence for the most holistic picture possible. The main issues are (1) which diabetic drugs cross the placenta, (2) the quality of evidence and data source validity, (3) the rationale for the designation of glucose control as the primary outcome in gestational diabetes mellitus, and (4) which drugs (metformin, glyburide, or insulin) are most effective in improving secondary outcomes. The concept that 1 drug fits all, whether it be insulin, glyburide, or metformin, is a fallacy. Different drugs provide certain benefits but not all the benefits and not to all patients. In addition, the steps in the gestational diabetes mellitus management decision path and the current cost of the use of insulin, glyburide, or metformin are addressed. In the future, we must consider studying the potential of diabetic drugs that currently are used in nonpregnancy and incorporating the concept of precision medicine in the decision tree to maximize pregnancy outcomes.

Metformin treatment of type 2 diabetes mellitus in pregnancy: update on safety and efficacy

With the increasing prevalence of type 2 diabetes mellitus (T2DM) in women of childbearing age, prescribing antidiabetic medications in first-trimester pregnancy is becoming more common. Metformin treatment during this time is usually avoided in countries with well-resourced healthcare. This is based on historical concerns about safety to the foetus and the widespread availability of insulin. However, there is now increasing interest in the potential benefits of metformin in pregnant women with T2DM. In this commentary, the main evidence supporting metformin safety in pregnancy is summarized, with an emphasis on the first trimester. Based on a structured literature search, the recent randomized controlled trials comparing metformin and insulin are reviewed. We then show that prescribing advice for metformin in pregnancy is inconsistent and product information/package inserts (PI) are universally out of date. This causes confusion and pushes some women and their clinicians to change from metformin to insulin. The potential advantages of metformin in pregnant women with T2DM are then discussed, including oral dosing and improved acceptability, lower resource utilization and cost, decreased insulin requirements, less maternal weight gain and less risk of maternal and neonatal hypoglycaemia. The conclusion is that metformin is a cheap and efficacious antidiabetic medication for many pregnant women with T2DM, with reasonable evidence for safety. Drug information resources should be updated so that metformin can be considered more broadly in women with T2DM who present for antenatal care.

Metformin use in pregnancy: promises and uncertainties

Metformin has been prescribed in pregnancy for over 40 years; for much of this time, use has been limited both in numbers and geographically, and the evidence base has been confined to observational studies. In early years, perceived safety concerns and lack of availability of the drug in many countries acted as a barrier to use. More recently, RCTs have begun to examine the role of metformin in pregnancy in much-needed detail. However, this evidence base has been interpreted differently in different countries, leading to very wide variation in its current application in pregnancy. In this short review, we will discuss the history of metformin in pregnancy and highlight some of the key clinical trials. We will then consider some of the remaining controversies associated with metformin use in pregnancy, most important of these being the potential for long-term 'programming' effects on the fetus as a result of metformin being able to cross the placenta. We will also consider clinical situations where metformin might be avoided. Finally, we will discuss some future directions for this drug as it reaches its sixtieth anniversary.

Oral Antidiabetic Agents in Pregnancy and Lactation: A Paradigm Shift?

Objective:

To provide information on the use of oral antidiabetic agents in pregnancy and breast-feeding.

Data Sources:

Primary articles were identified by a MEDLINE search (1966–March 2007) using the MeSH headings: pregnancy in diabetics, pregnancy, polycystic ovary syndrome, hypoglycemic agents, glipizide, glyburide, metformin, rosiglitazone, pioglitazone, clinical trial, controlled clinical trial, multicenter study, randomized controlled trial, case–control studies, and cohort studies.

Study Selection and Data Extraction:

All studies using oral antidiabetic agents in pregnancy were evaluated and relevant data were included in the discussion.

Data Synthesis:

Studies of glyburide and glipizide have found little or no transfer of these drugs across the placenta, whereas metformin and rosiglitazone cross readily. Animal studies have found no evidence to suggest that glyburide, glipizide, metformin, or rosiglitazone are teratogenic. In gestational diabetes, glyburide was safe and efficacious; however, 16–19% of women failed to achieve optimal glucose control. No developmental toxicity in infants was observed when metformin was used before and throughout pregnancy in women with polycystic ovarian syndrome (PCOS). Some of the studies involving patients with type 2 diabetes had methodological problems. A randomized controlled trial using metformin for gestational diabetes in the third trimester is underway. The human information is inadequate to evaluate the risk of glipizide or the thiazolidinediones in pregnancy. In breast milk, 3 studies measured nonsignificant amounts of metformin and one study was unable to detect either glyburide or glipizide.

Conclusions:

Neither glyburide nor metformin has caused developmental toxicity in humans. Glyburide has been used for the treatment of gestational diabetes, and metformin has been used in women with PCOS who eventually became pregnant. Additional trials are needed to better define the benefits and risks of oral antidiabetic agents in pregnancy. Metformin, glyburide, and glipizide appear to be compatible with breast-feeding.

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.

Improving outcomes of pregnancy for women with type 1 and type 2 diabetes

The pregnancy outcomes for women with type 1 diabetes remain poor with increased risk of major congenital malformation, stillbirth, premature delivery and perinatal death compared to the background maternity population. Despite clear evidence that women who attend prepregnancy care have improved blood glucose control with reduced risk of serious adverse outcomes, only a minority of women attend these clinics. For women with type 2 diabetes who are older, more obese and more likely to belong to an ethnic minority or live in an area of social deprivation, pregnancy outcomes are at least as poor as for women with type 1 diabetes. This is important as the prevalence of type 2 diabetes in women of reproductive years is increasing and even fewer women with type 2 diabetes attend prepregnancy care or take folic acid supplementation. Greater awareness regarding the risks among women with diabetes as well as primary and secondary healthcare professionals is required, if pregnancy outcomes are to be improved.

Pregnancy snapshot: a retrospective, observational case-control study to evaluate the potential effects of maternal diabetes treatment during pregnancy on macrosomia

OBJECTIVE

Pregnancy in women with diabetes is associated with increased incidence of macrosomia (high birth weight) versus women without diabetes. Macrosomia increases the risk of complications during delivery and neonatally. The potential effect on macrosomia incidence certain diabetes treatments may have is not fully established. This study aims to identify whether specific components of the prenatal care of mothers with diabetes are associated with increased macrosomia risk in a real-world U.S.

RESEARCH DESIGN AND METHODS

Retrospective, observational case-controlled study of mothers either without diabetes, or with type 1 (T1D), type 2 (T2D), or gestational diabetes mellitus (G.D.M.), using data from a U.S. insurance claims database. Treatment selection was at physician discretion.

MAIN OUTCOME MEASURE

Incidence of macrosomia.

RESULTS

For mothers with T2D, use of neutral protamine Hagedorn (N.P.H.) insulin and glyburide increased during pregnancy, from 3.4% to 33.3%, and 3.7% to 16.5%, respectively. The most common G.D.M. treatments during pregnancy were glyburide (15.5%), N.P.H. (12.9%), basal-bolus therapy (10.0%), and metformin (8.1%). Endocrinologist care during pregnancy was associated with insulin use - but not glyburide use - for mothers with G.D.M., and with insulin use for mothers with T1D and T2D (compared with mothers not visiting an endocrinologist). Glyburide was associated with higher odds for macrosomia: G.D.M. (odds ratio [O.R.] 1.53, 95% confidence interval [C.I.] 1.38-1.69, p < 0.0001); T2D (O.R. 1.93, 95% C.I. 1.51-2.47, p < 0.0001). Endocrinologist care was associated with lower odds for macrosomia overall (O.R. 0.86, 95% C.I. 0.81-0.92) and for mothers with G.D.M. (O.R. 0.85, 95% C.I. 0.75-0.97, p = 0.0156) when the sub-populations were examined in separate models.

CONCLUSIONS

Healthcare utilization and endocrinologist care were related to positive birth outcomes, especially with G.D.M. Further research into the safety and efficacy of glyburide in pregnancy is warranted. This study cannot infer causality and may not be representative of current U.S. healthcare practice.

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).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Metformin treatment for Type 2 diabetes in pregnancy?

Metformin lowers blood glucose by reducing hepatic glucose output, increasing insulin sensitivity and enhancing peripheral glucose uptake. Metformin is widely used in women with Type 2 diabetes of child-bearing age, many of whom become pregnant. Studies to date in Type 2 diabetes in pregnancy, gestational diabetes and polycystic ovarian syndrome are reassuring. Metformin is not considered teratogenic. There is sufficient evidence that metformin is safe used throughout pregnancy, with no worsening of obstetric or perinatal outcomes. Women may benefit from the lesser weight gain. The long-term risks to the offspring remain inadequately researched, with no evidence of harm up to 2 years, and no suggestions of later complications in countries using metformin for many years. Metformin is recommended for use in pregnancies complicated by Type 2 diabetes, but women should be informed of the evidence regarding its associated risks and benefits to enable an informed choice over its use.

Can Pregnant Diabetics be Treated with Glyburide?

Until the last decade, oral hypoglycemic agents have not been recommended in pregnancy owing to fear of their potential adverse fetal effects, including teratogenicity and neonatal hypoglycemia. However, the evidence in support of these recommendations is weak and is principally based on case series involving the use of first-generation sulfonylureas. Studies using a single-cotyledon placental model have found glyburide to only minimally cross the placenta, an observation that paved the way for a landmark randomized clinical trial that found glyburide to be as safe and effective as insulin in the management of gestational diabetes mellitus. Still, contradicting results regarding its trans-placental transfer, lack of adequate data regarding its safety during the first trimester and reports of increased neonatal morbidity raise concerns regarding the universal application of glyburide as an alternative to insulin therapy in diabetic pregnant women. Thus, there is a need for large, randomized, controlled trials with adequate power to evaluate the possibility of increased neonatal metabolic complications as well as the long-term outcome of infants born to mothers treated with glyburide and insulin. Unless future studies refute current data regarding the efficacy and safety of glyburide, we believe that, owing to its ease of administration, convenience and low cost, glyburide will become the first line of medical treatment in patients with gestational diabetes mellitus within the next few years.

GESTATIONAL DIABETES MELLITUS

Gestational diabetes (GDM) is defined as “carbohydrate intolerance of variable severity with onset or first recognition during pregnancy.” The definition is applicable regardless of whether insulin is used for treatment or the condition persists after pregnancy. It does not exclude the possibility that unrecognized glucose intolerance may have antedated the pregnancy”. GDM complicates 3–15% of all pregnancies and is a major cause of perinatal morbidity and mortality, as well as maternal long term morbidity. Of all types of diabetes, gestational diabetes (GDM) accounts for approximately 90–95% of all cases of diabetes in pregnancy.

Determination of metformin transfer across the human placenta using a dually perfused ex vivo placental cotyledon model

OBJECTIVE

The aim of the study was to quantify and characterize metformin transfer across the human placenta using an ex vivo placental perfusion model.

STUDY DESIGN

Placentas were obtained from vaginal deliveries or caesarean sections and selected cotyledons were cannulated and dually perfused. Metformin (1 microg/ml) and a permeability reference marker, antipyrine (50 microg/ml), were added to the maternal circulation. Each perfusion experiment was conducted for 180 min while samples were taken from the maternal and fetal compartments. The integrity and viability of the placenta were determined by measuring the flow rates, fetal artery inflow pressure, and hCG production during the experiments.

RESULTS

Six complete experimental set-ups were completed. The maternal-fetal transport rates for metformin and antipyrine were 10.61+/-2.85% and 30.98+/-5.62%, respectively. The clearance index, calculated as the ratio between the permeabilities of metformin and antipyrine, was 0.34+/-0.05.

CONCLUSION

The results indicate that metformin is able to cross the mature human placenta; thus, fetal exposure must be considered when treating pregnant women with metformin.

Oral anti-hyperglycemic agents for the management of gestational diabetes mellitus

The purpose of this review is to provide a brief overview for understanding the management guidelines of gestational diabetes. The rationale for the use of oral antidiabetic drugs is provided based on validation by appropriately conducted research trials. Concerns over teratogenicity due to possible placental transfer, neonatal and maternal outcome, and basic pharmacologic benefits are addressed.

Glyburide for the treatment of gestational diabetes. A critical appraisal

The clinical experience with glyburide treatment of GDM has moved ahead of the science. A single randomized controlled trial of glyburide versus insulin indicates that glyburide treatment can provide a relatively safe alternative to insulin therapy. Subsequent retrospective trials have shown that up to 20% of GDM patients, especially those with substantial pretreatment hyperglycemia, are likely to require adjunctive or alternative therapy with insulin. These follow-on trials have also demonstrated that glyburide treatment, compared with insulin, actually results in lower mean glucose values and a higher percentage of "excellent glycemic control" with fewer hypoglycemic episodes. With the emerging view that glyburide treatment compared with insulin improves glycemic profiles, it should be expected to reduce the frequency of newborn obesity. Larger randomized controlled trials are necessary to clarify this question and the concerns regarding neonatal metabolic morbidity in glyburide-treated offspring.

Insulins and oral hypoglycemic agents in pregnancy

Numerous studies have established a direct relationship between maternal levels of glycemic control and neonatal outcomes for pregnancies complicated by diabetes. The past several years have seen the addition of insulin analogues as well as many new oral agents to the pharmacological armamentarium available to treat diabetes. Insulin analogs (both rapid and long acting) are of potential interest for women with insulin-requiring diabetes because of the improved control reported in non-pregnant individuals. Insulin lispro is the only insulin analog to be systematically studied in pregnancy. At this time, the majority of evidence suggests that insulin lispro does not cross the placenta and does not have adverse maternal or fetal effects during pregnancy in women with diabetes. For women with gestational diabetes mellitus (GDM) and type 2 diabetes, which are characterized by insulin resistance and relatively decreased insulin secretion, treatment with oral hypoglycemic agents is generating much excitement. Most retrospective studies and the published clinical experience have failed to demonstrate an increased risk of neonatal hypoglycemia and other neonatal morbidities with glyburide or metformin. To date there has been only one randomized controlled trial utilizing glyburide, which found it to be safe and effective in the management of GDM. More intensive investigation regarding the safety and feasibility of oral agents in pregnancies complicated by type 2 diabetes is necessary.

Role of ATP-sensitive potassium channels in normal and hypertension-associated pregnancy in rats

1. Activation of vascular ATP-sensitive K(+) (K(ATP)) channels has been implicated in vasodilator responses to pregnancy. 2. The effect of glibenclamide, a K(ATP) channel inhibitor, on systolic blood pressure (SBP) and renal function was evaluated in pregnant and non-pregnant spontaneously hypertensive rats, as well as in normotensive and hypertensive Wistar rats that had been made hypertensive by simultaneous treatment with N(G)-nitro-l-arginine methyl ester (0.4 mg/mL) and indomethacin (2 mg/kg, i.p.) from Day 1 of gestation. Pregnant animals received 10 mg/kg glibenclamide for 12 days starting at Day 7. In addition, the mRNA levels of the vascular K(ATP) channel (Kir6.2) were estimated in aorta and kidney using real-time reverse transcription-polymerase chain reaction on Day 19 of pregnancy. 3. The decreased SBP observed in pregnant Wistar rats was paralleled by an increase in Kir6.2 mRNA levels. Glibenclamide blunted systemic vasodilation and reduced the mRNA expression of Kir6.2. There was no pregnancy induced vasodilation and no change in Kir6.2 mRNA expression in SHR. Glibenclamide had no effect on pregnant SHR. Hypertensive Wistar rats exhibited high SBP, followed by increased Kir6.2 mRNA levels. The effects of glibenclamide were not evaluated in this group because glibenclamide induced intense vaginal bleeding. 4. The results of the present study suggest that K(ATP) channels may be involved in pregnancy induced vasodilation during normotensive pregnancy, but not in pregnant SHR. Glibenclamide may have an abortive effect if administered during the early phases of gestation or in association with nitric oxide and prostaglandin inhibitors.

Pregnancy outcome in type 2 diabetes mellitus: a retrospective analysis from the Netherlands

MAIN OBJECTIVES

The objective was to describe pre-gestational history and the maternal, fetal and neonatal outcome in pregnancies in women with pre-gestational type 2 diabetes during the period between 1992 and 2006 from one center in the Netherlands.

METHODS

Patients attending the obstetric-diabetology outpatient clinic of a tertiary referral center were studied. This center also has a regular diabetes clinic and a community midwifery service. Patients were identified from the database. Maternal outcome (pre-eclampsia, pre-term delivery, Caesarean section) and fetal and neonatal outcome (macrosomia, congenital malformations, perinatal mortality, neonatal hypoglycemia) were analyzed as well HbA1c levels, planning of pregnancy, gestational age at first antenatal visit and ethnic background.

RESULTS

Sixty-six singleton pregnancies from 48 women were analyzed. Their age was 34 +/- 5 yr, the BMI 31.7 +/- 7.4 and the median duration of diabetes was 3 yr. 52% were Caucasian and 35% were of Moroccan descent. 49% did not complete secondary school. Moroccan descent was associated with a lower educational level and a BMI comparable with the whole study group. The proportion of planned pregnancies was approximately 70%. The mean HbA1c in the first trimester was 6.4 +/- 1.1% and the gestational age at first visit was 10 +/- 5 wk, in one-quarter before 6 wk. The prevalences of variables related to maternal and neonatal outcome were as follows: spontaneous abortion 13.6%, pre-eclampsia 8.9%, pre-term delivery 21.4%, spontaneous labor 25.0%, induced labor 48.2%, Caesarean section 42.9%, macrosomia (>/=90th percentile) 41.1%, severe hypoglycemia 41.5% and major congenital malformations 5.1%.

CONCLUSIONS

Pre-gestational type 2 diabetes is associated with an increased incidence of adverse pregnancy outcome despite reasonable mean HbA1c level and despite a high frequency of planned pregnancies. Many women report relatively late. Improvement in the outcome requires more active peri-gestational specialist care and a tailored approach is required towards migrant communities.

Pregnancy outcome after first-trimester exposure to metformin: a meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of pregnancy outcome after metformin use for polycystic ovary syndrome (PCOS), because the efficacy of metformin has been demonstrated in the treatment of infertility caused by PCOS, whereas the fetal safety of metformin has received very little attention, and the few studies addressing this issue are limited by small sample sizes.

DESIGN

Meta-analytic review.

SETTING

All pertinent studies in MEDLINE and EMBASE from 1966 to September 2004.

PATIENT(S)

Women with PCOS or diabetes.

INTERVENTION(S)

Exposure to metformin in the first trimester of pregnancy.

MAIN OUTCOME MEASURE(S)

Major malformations.

RESULT(S)

Eight studies were included in the meta-analysis, with an odds ratio of 0.50 (95% confidence interval, 0.15, 1.60). After adjustment for publication bias, metformin treatment in the first trimester was associated with a statistically significant 57% protective effect. After pooling the studies, the malformation rate in the disease-matched control group was approximately 7.2%, statistically significantly higher than the rate found in the metformin group (1.7%).

CONCLUSION(S)

On the basis of the limited data available today, there is no evidence of an increased risk for major malformations when metformin is taken during the first trimester of pregnancy. Large studies are needed to corroborate these preliminary results.

The science behind 25 years of ovarian stimulation for in vitro fertilization

To allow selection of embryos for transfer after in vitro fertilization, ovarian stimulation is usually carried out with exogenous gonadotropins. To compensate for changes induced by stimulation, GnRH analog cotreatment, oral contraceptive pretreatment, late follicular phase human chorionic gonadotropin, and luteal phase progesterone supplementation are usually added. These approaches render ovarian stimulation complex and costly. The stimulation of multiple follicular development disrupts the physiology of follicular development, with consequences for the oocyte, embryo, and endometrium. In recent years, recombinant gonadotropin preparations have become available, and novel stimulation protocols with less detrimental effects have been developed. In this article, the scientific background to current approaches to ovarian stimulation for in vitro fertilization is reviewed. After a brief discussion of the relevant aspect of ovarian physiology, the development, application, and consequences of ovarian stimulation strategies are reviewed in detail.

Pregnancy in women with Type 2 diabetes: who takes metformin and what is the outcome?

AIMS

To review pregnancy outcomes in women with Type 2 diabetes (Type 2 DM), comparing women treated with those not treated with metformin.

METHODS

Data were collected by case-note review for all pregnancies in women with Type 2 DM over a 6-year period (1998-2003) at the National Women's Hospital. Two hundred and fourteen pregnancies were included, metformin was taken in 93 pregnancies and continued until delivery in 32; the remaining 121 pregnancies comprised the control group. The principal outcome measures were preeclampsia, perinatal loss and neonatal morbidity.

RESULTS

Baseline characteristics differed between groups: women in the metformin group had greater mean (SD) body mass index [35.5(7.6) vs. 33.5(6.6) kg/m2, P < 0.05], more chronic hypertension (19% vs. 7%, P < 0.05) and higher mean (SD) first trimester glycated haemoglobin (HbA1c) levels [8.3(1.9)% vs. 7.5(1.7)%, P < 0.005]. There was no difference between metformin and control groups, respectively, in the rate of preeclampsia (13% vs. 14%, P = 0.84), perinatal loss (3% vs. 2%, P = 0.65) or neonatal morbidity, including rate of prematurity (23% vs. 22%, P = 0.7), admission to the neonatal unit (40% vs. 48%, P = 0.27), respiratory distress (9% vs. 18%, P = 0.07) and treatment with intravenous dextrose (20% vs. 31%, P = 0.08).

CONCLUSIONS

Pregnant women with Type 2 DM who were treated with metformin had more risk factors for adverse pregnancy outcomes, but no differences in outcomes were seen compared with women not taking metformin. We need randomized trials to address potential benefits of metformin treatment in this population that may be masked by current practice.

Diabetes and pregnancy

Diabetes in pregnant women is associated with an increased risk for maternal and neonatal morbidities and remains a significant medical challenge. Fortunately, the prognosis has changed dramatically, related to an increased clinical awareness of the potential risks for the mother and the infant, better health care and intensive treatment strategies to maintain the closest to normal metabolic milieu. Diabetes and pregnancy may be divided into pregestational diabetes (women previously diagnosed with type 1 or type 2 diabetes) and gestational diabetes defined as any glucose intolerance detected during pregnancy that has evolved from a diagnosis associated with the metabolic risk of type 2 diabetes to a clinical condition associated with higher risks for maternal and perinatal morbidity. Early diagnosis of gestational diabetes is an important step to improve outcomes and systematic or selective screening with the OGTT should be established. Associated with the global epidemic in diabetes, pregnancy associated with diabetes is saturating high-risk obstetric clinics and neonatal intensive care units, becoming a heavy burden to the health care systems around the world.

Gestational diabetes: a review of the treatment options

More than three decades since the original published description of gestational diabetes mellitus (GDM), no consensus exists regarding its implications or management. Targeting fetal macrosomia as the greatest morbidity, treatment strategies for this pregnancy-induced disease of insulin resistance have largely been modeled from therapies proven successful in pregnant women with type 2 diabetes mellitus. Surrounded by a rapidly expanding array of treatment options for insulin-resistant diabetes, potentially legitimate concerns about teratogenicity and fetal metabolic effects have limited clinical trials of insulin analogs and oral antihyperglycemic agents during pregnancy. So far, only insulin lispro and glyburide (glibenclamide) have been tested prospectively in randomized trials of women with GDM. In limited studies, both of these agents have compared favorably with standard insulin regimens, and neither appear to cause any fetal or neonatal harm. Although acknowledged by the American Diabetes Association (ADA) and the American College of Obstetricians and Gynecologists (ACOG), these seminal studies have not yet prompted a recommendation from either organization on how to utilize insulin analogs or oral antihyperglycemic agents in the treatment of GDM. Although they lack an evidence base for many therapeutic strategies for GDM, the current ADA and ACOG guidelines still provide a reasonable set of treatment recommendations.

Recent advances in the treatment of gestational diabetes

Despite four decades of research there is a lack of international consensus on the screening, diagnosis, treatment and follow up of gestational diabetes mellitus (GDM). Currently, GDM is managed by diet modification, exercise and exogenous human insulin. During the last decade, several insulin analogues and oral antihyperglycaemic drugs have revolutionised the management of diabetes mellitus in non-pregnant women. Most of these recent drugs still remain investigational in GDM due to concerns about their safety in pregnancy. This review will focus primarily on the pharmacological treatment of GDM. It will objectively assess the value of these exciting new drugs in pregnancy as they could potentially benefit every woman with GDM.

Should we continue or stop insulin sensitizing drugs during pregnancy?

PURPOSE OF REVIEW

The use of insulin sensitizing drugs such as metformin in polycystic ovary syndrome has been increasingly popular and validated by systematic reviews. There has also been an interest in the use of metformin for gestational diabetes. However, administration of metformin to prevent miscarriage is controversial and widespread use of this drug in early pregnancy requires investigation.

RECENT FINDINGS

There are claims that miscarriage and gestational diabetes are more common in polycystic ovary syndrome and that use of insulin sensitizers improves outcomes dramatically. This review suggests there is no evidence for increased risk of miscarriage solely due to polycystic ovary syndrome and that there are insufficient data for promoting therapy with metformin. There is some reason for use of metformin in mid-pregnancy for gestational diabetes but better evidence from randomized controlled trials is urgently needed.

SUMMARY

The use of metformin in early pregnancy for reducing the risk of miscarriage should be avoided outside of the context of properly designed prospective randomized trials. Safety in early pregnancy appears to be reassuring but not completely proven. The use of metformin in mid-pregnancy for gestational diabetes appears more logical but also needs adequate trials before general use is advocated.

Drugs that affect the fetus and newborn infant via the placenta or breast milk

In general, drugs that are taken by a mother during pregnancy or after birth may be transferred to the fetus or the infant (through breast milk). Many factors are involved that determine the amount of drugs that are transferred and their potential effects on the fetus or infant. A careful assessment of the risk versus benefit is necessary and should be individualized. In the breastfed infant, many measures can be undertaken further so that the amount of drug transferred to the infant is minimized.

Oral Hypoglycemic Agents in Pregnancy

Pregnancies in diabetic women are associated with increased risk of spontaneous abortion, congenital malformations, preeclampsia, preterm labor, macrosomia, shoulder dystocia, and cesarean section. Advances in antepartum cares and strict adherence to dietary and insulin regimens have been shown to significantly reduce the rate of maternal morbidity as well as perinatal morbidity and mortality. Historically, reports of potential fetal teratogenicity and hypoglycemic effects on the fetus contraindicated the use of oral hypoglycemic agents in pregnancies complicated with either type II diabetes mellitus (DM) or gestational diabetes mellitus (GDM). Recently, physicians increasingly prescribe newer generations of oral hypoglycemic agents to treat GDM and type II DM to pregnant patients. This review addresses the safety, current recommendations, and controversies surrounding use of the available oral hypoglycemic agents during pregnancy.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the mechanisms of actions of the various oral hypoglycemic agents, to list the known side effects of these agents, and to summarize the data on the use of these agents during pregnancy.

Is There a Role for Oral Antihyperglycemics in Gestational Diabetes and Type 2 Diabetes during Pregnancy?

Diabetes mellitus is a heterogeneous disorder of glucose intolerance that is generally classified into the following categories: type 1 and type 2 diabetes and gestational diabetes (GDM). Currently, the number of pregnancies complicated by type 2 diabetes and GDM exceed those affected by type 1 diabetes. Numerous studies have established a direct relationship between maternal glycemic control and neonatal outcomes for all types of diabetes. Therefore, modern treatment protocols during pregnancy emphasize strict glycemic control by a combination of diet and medication. Traditionally, insulin therapy has been considered the gold standard for management because of its efficacy in achieving tight glucose control and the fact that it does not cross the placenta. Since GDM and type 2 diabetes are characterized by insulin resistance and relatively decreased insulin secretion, treatment with oral antihyperglycemic agents that target these defects is of potential interest. However, because of concerns regarding transplacental passage and, therefore, the possibility of fetal teratogenesis and prolonged neonatal hypoglycemia, these agents are not currently recommended in pregnancy. There are no randomized controlled trials on which to draw conclusions regarding the teratogenicity of these oral agents. However, most retrospective studies and the published clinical experience have not demonstrated an increased risk of malformed infants among women treated with oral antihyperglycemic agents. Rather, the data indicate that the increased risk for major congenital anomalies appears to be related to maternal glycemic control prior to and during conception. These studies and currently available data on the use of both metformin and sulfonylureas in pregnancy have also failed to demonstrate an increased risk of neonatal hypoglycemia and other neonatal morbidities. To date, there has only been one randomized controlled trial to test the effectiveness and safety of sulfonylurea therapy (glyburide [glibenclamide]) in the management of women with GDM. Both the insulin- and glyburide-treated women were able to achieve satisfactory glucose control and had similar perinatal outcomes. Glyburide was not detected in the cord serum of any infant in the glyburide group. In summary, based on the currently available data, it appears that glyburide could be safely and effectively utilized in the management of GDM. However, more intensive investigation regarding the safety and feasibility of oral agents in pregnancies complicated by type 2 diabetes is necessary. It is important to emphasize that it is the level of metabolic control achieved and not the mode of therapy that is crucial to improving outcomes in these pregnancies.

Adverse pregnancy outcome in rats following exposure to a Salacia reticulata (Celastraceae) root extract

The root extract of Salacia reticulata Wight (family: Celastraceae) is used in Sri Lanka by traditional practitioners as a herbal therapy for glycemic control even during pregnancy. It is recognized that some clinically used antidiabetic drugs have harmful effects on pregnancy but the effects of the S. reticulata root extract on reproductive outcome is unknown and deserves examination. We determined the effects of the S. reticulata root extract on the reproductive outcome of Wistar rats (250-260 g) when administered orally (10 g/kg) during early (days 1-7) and mid- (days 7-14) pregnancy. The root extract significantly (P<0.05) enhanced post-implantation losses (control vs treatment: early pregnancy, 4.7 2.4 vs 49.3 13%; mid-pregnancy, 4.7 2.4 vs 41.7 16.1%). Gestational length was unaltered but the pups born had a low birth weight (P<0.05) (early pregnancy, 6.8 0.1 vs 5.3 0.1 g; mid-pregnancy, 6.8 0.1 vs 5.0 0.1 g) and low birth index (P<0.05) (early pregnancy, 95.2 2.4 vs 50.7 12.9%; mid-pregnancy, 95.2 2.4 vs 58.3 16.1%), fetal survival ratio (P<0.05) (early pregnancy, 95.2 2.4 vs 50.7 12.9; mid-pregnancy, 95.2 2.4 vs 58.3 16.1), and viability index (P<0.05) (early pregnancy, 94.9 2.6 vs 49.5 12.5%; mid-pregnancy, 94.9 2.6 vs 57.1 16.1%). However, the root extract was non-teratogenic. We conclude that the S. reticulata root extract can be hazardous to successful pregnancy in women and should not be used in pregnancy complicated by diabetes.

Prescription drugs and pregnancy

Prescribing drugs in pregnancy is an unusual risk-benefit situation. Drugs that may be of benefit or even life-saving to the mother can deform or kill the fetus. However, the risk to the fetus should not be exaggerated. There are only approximately 20 drugs or groups of drugs which are known to cause birth defects in humans. For one of these drugs to cause birth defects, a number of criteria must be fulfilled. The drug exposure must take place at a critical stage of pregnancy and the dose must be high enough to cause a threshold of exposure for an appropriate duration of time. For most of the known human teratogens, > 90% of pregnancies exposed during the first trimester result in normal offspring. Although only a few drugs are known to cause birth defects in humans, uncertainty about the safety of the majority may lead to underprescribing for pregnant women and women of childbearing age. Epidemiological studies of pregnancy outcome after specific drug exposures are often superficially reassuring, but most are severely limited in their power to detect adverse outcomes. Safety in animal studies may also be reassuring but species differences demand caution in this interpretation. Concerns about prescription drugs in the first trimester, when they can cause birth defects, are mostly quite different to concerns about use in the second and third trimesters. As the fetal organ systems mature, the fetus can be affected by the pharmacological activity of the drug in the same way as the mother. Many drugs have pharmacological effects on the fetus in the second and third trimesters but in most cases, they are well recognised and can be managed or avoided. The material presented in this paper is mostly concerned with the 'risks' associated with drugs in pregnancy. No attempt has been made to quantitate the possible benefits to the mother or fetus. Communicating the risk-benefit situation to the patient is always a challenge for physicians with limited time and sometimes limited knowledge. Fear of litigation is an unfortunate and an unwanted parameter in the assessment. Better knowledge of the parameters that determine teratogenicity may allow physicians to feel more confident in assessing the risks and benefits associated with prescribing in pregnancy.

Oral antihyperglycemic agents during pregnancy and lactation: a review

The treatment approach of diabetes mellitus during pregnancy requires a combination of diet, exercise, multiple home glucose determinations and intensive insulin regimens. During the last decade there was an increased interest in the use of oral antihyperglycemic agents (OAHAs) as an alternative to insulin in achieving good glycemic control. OAHAs are divided into four groups: derivatives of sulfonylurea, biguanides, glucosidase inhibitors and thiazolidinediones. This review describes the possible teratogenic effects of the use of OAHAs during pregnancy and the effects of these drugs during lactation. Animal and human studies assessing the teratogenic effects of OAHAs have yielded conflicting data because the risk of major malformations in infants of mothers with diabetes appears to be related to maternal glycemic control rather than the antidiabetic therapy. A major concern with the use of OAHAs during pregnancy is neonatal hypoglycemia, which may be severe and persist for days. Therefore, insulin is still the drug of choice because it has not been implicated as a teratogen in human pregnancies. In addition, because of the lack of data regarding the use of OAHAs in pregnancy, we cannot draw firm conclusions about all of the available drugs. However, OAHAs, especially glibenclamide (glyburide), may be beneficial in a situation where the proper use of insulin is problematic. Because there are very limited clinical data on the exposure of OAHAs to the infant via breast milk, and the potentially serious effect of neonatal hypoglycemia, the safest recommendation is not to breast feed while taking OAHAs. Well-conducted, prospective, controlled studies regarding the feasibility of OAHAs in pregnant women with diabetes and during lactation are needed.

Use of antidiabetes agents in pregnancy: current practice and controversy

Prior to the discovery of insulin, the combination of diabetes and pregnancy was considered potentially lethal. Advances in the care of diabetes, combined with advances in antepartum fetal testing, have reduced maternal and perinatal mortality outcomes to levels expected in nondiabetic pregnancies. As new oral antidiabetes medications are introduced, the safety and efficacy of using them during pregnancy are under investigation. This article describes the oral medications currently available to treat diabetes, reviews the body of research available on these agents, and discusses current recommendations and controversies.

Glyburide compared to insulin for the treatment of gestational diabetes mellitus: a cost analysis

OBJECTIVE

To compare the costs associated with glyburide compared to insulin for the treatment of gestational diabetes unresponsive to dietary therapy.

STUDY DESIGN

A cost model was designed. The model excluded costs that were identical for both treatment arms, such as the cost of monitoring glucose control. Insulin treatment costs included average wholesale drug costs, wholesale delivery costs (syringes, alcohol pads), and costs of office staff educating patients. Glyburide costs were based on average wholesale drug costs. Downstream costs of potential inpatient evaluation for hypoglycemia were included in the model.

RESULTS

In our baseline model, glyburide was significantly less costly than insulin for the treatment of gestational diabetes. The average cost saving per patient based on wholesale drug costs and hospital costs was US$165.84. Actual retail drug savings and hospital charge savings are potentially considerably greater. The strongest determinant of cost savings was medication cost. The model was less sensitive to the one-time costs of inpatient treatment and patient education.

CONCLUSION

Glyburide is less costly than insulin for the treatment of gestational diabetes. Cost models can be useful to physicians deciding between two equally efficacious medications, allowing them to incorporate information about their individual practice styles with a complex balance of cost implications.