Metformin in obstetric and gynecologic practice: a review

Clinical outcomes in non-small-cell lung cancer patients receiving concurrent metformin and immune checkpoint inhibitors

Aim:

To study the clinical benefits of concurrent metformin and immune checkpoint inhibitors (ICIs) in non-small-cell lung cancer patients.

Materials & methods:

This is a retrospective review of 50 non-small-cell lung cancer patients receiving ICIs with metformin (cohort A) or without metformin (cohort B). Patients were also stratified by ICIs as second-/third-line therapy.

Results:

Overall response rate and disease control rate were higher in cohort A (41.1 vs 30.7%, p = 0.4 and 70.5 vs 61.6%, p = 0.5, respectively). Median overall survival and progression-free survival were also higher in cohort A (11.5 vs 7.6 months, p = 0.5 and 4.0 vs 3.0 months, p = 0.6, respectively). On subset analysis (second-/third-line ICIs), overall response rate, disease control rate, median overall survival, progression-free survival were also higher in cohort A.

Conclusion:

Despite the small-sample size, we observed improved clinical outcomes in patients who received ICIs in combination with metformin.

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advice for metformin in pregnancy is inconsistent and product information/package inserts (PI) are universally out of date.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.

The efficacy of metformin in pregnant women with polycystic ovary syndrome: a meta-analysis of clinical trials

OBJECTIVES

The role of metformin in the treatment of pregnant women with polycystic ovary syndrome (PCOS) is controversial. Therefore, we evaluated whether the use of metformin during pregnancy in women with PCOS could reduce pregnancy-related complications.

RESEARCH DESIGN AND METHODS

MEDLINE was searched to retrieve relevant trials. In addition, reviews and reference lists of the retrieved articles were scanned for further appropriate studies. The primary outcome measure was the incidence of complications of pregnancy, which included early pregnancy loss (EPL), gestational diabetes (GDM), pre-eclampsia (PE), and pre-term delivery (PD).

RESULTS

In total, eight studies with 1106 patients were included. The pooled odds ratio (OR) (95% confidence interval) of outcome for pregnant women with PCOS prescribed metformin were 0.32 (0.19-0.55) for EPL, 0.37 (0.25-0.56) for GDM, 0.53 (0.30-0.95) for PE and 0.30 (0.13-0.68) for PD.

CONCLUSIONS

Metformin therapy throughout pregnancy decreased the OR of EPL, GDM, PE, and PD in pregnant PCOS women with no serious detrimental side effects.

Management of gestational diabetes by physicians in Turkey

AIMS

We sought to investigate the practice patterns of clinicians (family physicians, internists and obstetricians) in Turkey in screening for gestational diabetes mellitus (GDM), management and monitoring of hyperglycaemia in pregnant women with GDM, and assessment of glucose tolerance in the postpartum state.

METHODS

Between January and December 2007, current practices of Turkish physicians (n=434) were assessed by a questionnaire which was concerned with physician demographics and clinical practice including screening and diagnostic methods for GDM, management of GDM during pregnancy and postpartum assessment of glucose tolerance. The questionnaire was developed in respect to the recommendation of the Fifth International Workshop-Conference on GDM and the standards of the American Diabetes Association (ADA).

RESULTS

Although most of the physicians stated that they performed screening for GDM and postpartum screening for glucose intolerance in women with GDM, their screening practices vary. The proportion of women who were provided with a nutrition counselling by a registered dietician and a patient education by a trained nurse was low, especially in women treated by the family physicians. Home glucose monitoring was widely used in the management of GDM, however, postprandial glucose assays were used occasionally. Regular and NPH insulin preparations were the most preferred drugs to treat GDM. Internists were more likely to use insulin analogues. On the other hand, a significant number of physicians stated that they used oral antidiabetics (OADs). A considerable number of family physicians used OADs which have not been proved to be safe in pregnancy.

CONCLUSIONS

Our results suggest that there is considerable variation in the clinical practice patterns of physicians. An education program to enhance the clinical aptitude of physicians, particularly family physicians, in the medical management of GDM should be designed throughout the country.

The role of insulin-sensitizing agents in the treatment of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) represents a heterogeneous spectrum of disorders, mainly characterized by chronic oligoanovulation and hyperandrogenism. Although not included in the diagnostic criteria, insulin resistance is recognized as a fundamental pathogenetic factor of the syndrome. Thus, the use of insulin-sensitizing drugs, such as metformin and thiazolidinediones, has been proposed for PCOS treatment. These agents are unique because they exert both metabolic and endocrine/ovarian beneficial effects. In this review the results of up-to-date clinical studies and meta-analyses on the possible gynaecological actions of insulin sensitizers are discussed. It has been shown that, as well as favourable metabolic influences, such as improvement in glucose, lipid and proinflammatory profiles, these agents also exert beneficial endocrine and ovarian effects, including amelioration of reproductive abnormalities, restoration of ovulation and menstrual cycles, increase in pregnancy rates and reduction of androgen production. Therefore, current data support the use of insulin sensitizers, along with lifestyle measures and/or other agents, in women with PCOS, especially in the presence of insulin- or clomifene-resistance.

Neonatal outcome in polycystic ovarian syndrome patients treated with metformin during pregnancy

OBJECTIVE

The present study aimed to evaluate the effect of metformin exposure during pregnancy on neonates of polycystic ovarian syndrome (PCOS) patients.

METHOD

Neonatal outcomes of 33 women with PCOS treated with metformin during pregnancy were compared to neonatal outcomes of 66 normal healthy women in a retrospective case-control study.

RESULTS

The mean birth weight percentile of neonates exposed to metformin in utero during the first trimester was significantly lower than that of neonates delivered to normal healthy matched controls. After controlling for pregnancy complications, this observation became only marginally statistically significant.

CONCLUSION

Although metformin is an attractive option for induction of ovulation in PCOS patients, there is a need for more evidence related to its safety during pregnancy.

Outcome of clinical pregnancies after ovulation induction using metformin

The objective of this study was to review the first 50 clinical pregnancies of women with polycystic ovarian syndrome (PCOS) who had ovulation induced either with metformin alone, or in combination with clomifene. The study was confined to women with PCOS attending our infertility service. A register of clinical pregnancies was maintained of women who conceived after metformin therapy. The metformin was continued throughout the first trimester. The outcome of pregnancy was determined by individual chart review. Of the 50 women, 21 conceived with a combination of clomifene and metformin, and 29 with metformin alone. Seven women had a first trimester loss and 43 had a live birth. There were no perinatal deaths, no neonatal seizures and no congenital malformations. There were also no multiple pregnancies. The overall caesarean rate was 37%, and none of the babies had an Apgar score less than 7, at 5 min. This study found no evidence of any adverse clinical effects when metformin is continued in the first trimester of women with PCOS following ovulation induction. There was also no evidence of an increase in the rate of miscarriage or multiple pregnancy.

Continuation of metformin in the first trimester of women with polycystic ovarian syndrome is not associated with increased perinatal morbidity

This study aimed to assess the perinatal outcome, especially foetal growth, following the continuation of metformin during the first trimester of pregnancy. All women with polycystic ovary syndrome (PCOS) treated with metformin in the first trimester and who delivered a baby weighing 500 g or more between 2003 and 2005 were studied. Subjects were matched for age and parity with randomly selected controls. The perinatal outcomes studied were: growth parameters, gestational age, congenital defects, hypoglycaemia and neonatal unit admission. Sixty-six pregnancies were compared with 66 controls; all had singleton deliveries. There was no difference in mean birth weight between the metformin and the control groups (p=0.84). The percentage of small (<10th centile) and large (>90th centile) for gestational age babies was lower in the metformin group. In the metformin group, there were no major congenital malformations and 24% of the babies were admitted to the neonatal intensive care unit (NICU) compared with 27% of the babies in the control group (non-significant). Neonatal hypoglycaemia was less common in the metformin group (18.5% vs. 24.5%) and fewer babies required intravenous glucose therapy (6.3% vs. 12%). We found no evidence that the continuation of metformin in the first trimester of pregnancy was associated with an adverse foetal outcome.

Comparison of metformin and insulin in the treatment of gestational diabetes: a retrospective, case-control study

OBJECTIVES

Limited data are available on metformin therapy in gestational diabetes. The aim of the study was to compare maternal and neonatal outcomes in patients with gestational diabetes mellitus (GDM) treated with metformin with those treated with insulin, or diet alone.

STUDY DESIGN AND METHODS

We conducted a retrospective study that included 45 GDM women treated with metformin, 45 women treated with insulin and 83 women with no pharmacological treatment. Subjects were matched for pre-pregnancy body mass index (BMI) and age.

RESULTS

There were no differences between the metformin-treated group and the other two groups in terms of maternal outcomes (total weight gain during pregnancy or after the diagnosis of GDM, pre-pregnancy hypertension, pregnancy induced hypertension, pre-eclampsia etc.). In the diagnostic 2-hour oral glucose tolerance test, glucose values were slightly, but significantly, higher in the insulin group than in the metformin group (p < 0.003). Eighteen percent of mothers treated with metformin needed supplementary insulin therapy. No differences between the metformin-treated group and the other two groups (insulin, diet only) were observed in relation to mean birth weights, prevalence of macrosomia, or gestational weeks at delivery. The incidence of neonatal hypoglycemia was higher in the insulin group than in the metformin group (p = 0.03). There were no differences between the groups in other neonatal outcomes (small for gestational age, Apgar scores, umbilical artery pH or base excess, etc.).

CONCLUSION

These retrospective data suggest that metformin is effective in controlling gestational diabetes and is not associated with a higher risk of maternal or neonatal complications compared with insulin.

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.

Le syndrome des ovaires polykystiques (SOPK)

Polycystic ovaries syndrome (PCOS) is one of the most common female hormonal disorders. Its multiple components--reproductive, metabolic, neoplasic and cardiovascular--have a major impact on the public health. Androgen excess and resistance to insulin, probably from genetic origin, are responsible for most of the clinical symptomatology. Resistance to insulin seems to be accompanied by a greater risk of glucose intolerance, type 2 diabetes, lipidic anomalies and can involve the development of cardiovascular diseases. In addition, sleep apnea syndrome is more progressively described in PCOS. Infertility, menses disorders and hirsutism often push these patients to consult their physician. A better understanding of the physiopathological mechanisms led to the emergence of new therapeutic options increasing the sensitivity to insulin. Besides the pregnancy wishes, cares aim to attenuate the marks of the hyper-androgenism (hormonal treatment and cosmetic) and to correct cardiovascular, respiratory and gynaecological risk factors. In case of infertility by anovulation, cares must be performed by trained experts to minimize the risk of ovarian hyper-stimulation syndrome and multiple pregnancies. A gradation from loose weight to clomiphene citrate ovulation induction, ovarian drilling, low dose gonadotropin, in vitro fertilisation, or in vitro maturation of oocytes should bring back good reproduction potential.

Using evidence from randomized trials in fertility practice

Randomized controlled trials (RCTs) are central to the understanding of treatment effectiveness and diagnostic test utility. If they are to be relied upon in clinical practice, data from trials should have three main attributes: validity (be free from bias); clinical relevance (be based on patients similar to your own, reporting outcomes that matter to them); and importance (demonstrate effect sizes that are large enough to justify the costs and risks entailed). With these principles in mind, this brief article reviews key questions to pose while deciding whether new evidence from RCTs should influence subfertility patient care.

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.

Metformin prevents embryonic resorption induced by hyperandrogenisation with dehydroepiandrosterone in mice

The present study examined the mechanism by which metformin prevents dehydroepiandrosterone (DHEA)-induced embryonic resorption in mice. Treatment with DHEA (6 mg/100 g bodyweight, 24 and 48 h post implantation) induced 88 +/- 1 % embryonic resorption and the diminution of both serum oestradiol (E) and progesterone (P) levels. However, when metformin (50 mg/kg bodyweight) was given together with DHEA, embryo resorption (43 +/- 3% v. 35 +/- 5% in controls) and both serum E and P levels were not significantly different from controls. Glucose and insulin levels were increased in the DHEA-treated mice but when metformin was administered together with DHEA these parameters were similar to control values. Treatment with DHEA increased ovarian oxidative stress and diminished uterine nitric oxide synthase (NOS) activity; however, when metformin was administered together with DHEA, both ovarian oxidative stress and uterine NOS activity were not different from controls. Metformin treatment did not modify the percentage of CD4(+) and CD8(+) T cells from both axillar and retroperitoneal lymph nodes but prevented the increase of serum tumour necrosis factor +/- produced in DHEA-treated mice. These results show that metformin acts in DHEA-induced embryonic resorption in mice by modulating endocrine parameters, ovarian oxidative stress and uterine NOS activity.

Insulin analogue therapy in pregnancies complicated by diabetes mellitus

Pregnancies complicated by diabetes mellitus (DM) include pregestational DM and gestational DM, defined as carbohydrate intolerance of variable severity first detected during pregnancy. DM leads to poor pregnancy outcome. The aim of treatment is to control maternal hyperglycaemia and to imitate postprandial insulin release. Rapid-acting insulin analogues are suitable therapeutic candidates, as they are able to reduce postprandial hyperglycaemia (predictive of adverse pregnancy outcome). There is no excess risk of adverse fetal or maternal outcomes when compared with regular insulin. Data suggest that rapid-acting insulin analogues do not transfer to human placenta. Because of the reduced risk of hypoglycaemia and improved postprandial and overall glucose control, insulin analogues could be considered the rapid-acting insulin choice during pregnancy.

Association of Gly972Arg variant of insulin receptor substrate-1 with metabolic features in women with polycystic ovary syndrome

OBJECTIVE

To examine the prevalence and the effects of Gly972Arg (G972A) variant of insulin receptor substrate-1 (IRS-1) in women with polycystic ovary syndrome (PCOS).

DESIGN

Controlled clinical study.

SETTING

An academic clinical research center.

PATIENT(S)

Sixty women with PCOS and 60 control women matched for age.

INTERVENTION(S)

Biometric measures, metabolic and hormonal measures, genetic analyses.

MAIN OUTCOME MEASURE(S)

Serum androgens, glucose, and insulin were measured. Blood leukocytes were used for genetic analyses.

RESULT(S)

The G972A variant was encountered more often in women with PCOS. The G972A carriers were more obese than their counterparts, had higher fasting insulin levels, and were more insulin-resistant. However, androgen levels did not differ on the basis of IRS-1 genotype.

CONCLUSION(S)

We observed that the G972A variant of IRS-1 was more prevalent in women with PCOS, and that it had important metabolic effects without having a direct effect on the androgen levels. However, the G972A variant of IRS-1 may modulate reproduction by lowering sex hormone-binding globulin in both healthy women and women with PCOS.

Multiple gestation and infertility treatment: registration, reflection and reaction—the Belgian project

Multiple pregnancies associated with infertility treatment are recognized as an adverse outcome and are responsible for morbidity and mortality related to prematurity and very low birthweight population. Due to the epidemic of iatrogenic multiple births, the incidence of maternal, perinatal and childhood morbidity and mortality has increased. This results in a hidden healthcare cost of infertility therapy and this may lead to social and political concern. Reducing the number of embryos transferred and the use of natural cycle IVF will surely decrease the number of multiple gestations. Consequently, optimized cryopreservation programmes will be essential. For non-IVF hormonal stimulation, responsible for more than one-third of all multiple pregnancies after infertility treatment, a strict ovarian stimulation protocol aiming at mono-ovulation is crucial. Multifetal pregnancy reduction is an effective method to reduce high order multiplets but carries its own risk of medical and emotional complications. Excellent data collection of all infertility treatments is needed in our discussion with policy makers. The Belgian project, in which reimbursement of assisted reproduction technology-related laboratory activities is linked to a transfer policy aiming at substantial multiple pregnancy reduction, is a good example of cost-efficient health care through responsible, well considered clinical practice.