Antidiabetic medication use during pregnancy: an international utilization study

Can short- and long-term maternal and infant risks linked to hypertension and diabetes during pregnancy be reduced by therapy?

Hypertensive disorders of pregnancy (HDP), especially preeclampsia, and diabetes during pregnancy pose significant risks for both maternal and infant health, extending to long-term outcomes such as early-onset cardiovascular disease and metabolic disorders. Current strategies for managing HDP focus on screening, prevention, surveillance, and timely intervention. No disease-modifying therapies exist so far for established preeclampsia; delivery remains the definitive resolution. Preventive measures-including early pregnancy screening, exercise, and low-dose aspirin-show promise. Antihypertensive treatments reduce severe hypertension risks, whereas magnesium sulfate remains the standard for preventing eclampsia. Planned delivery from gestational week 37 can balance maternal benefits and neonatal risks in women with established preeclampsia. Delivery between 34 and 37 weeks gestation in women with preeclampsia has to balance risks for mother and infant. Lifestyle interventions-particularly diet and physical activity-are pivotal in managing gestational diabetes mellitus and type 2 diabetes. The oral antidiabetic metformin has shown benefits in glycaemic control and reducing maternal weight gain, although its long-term effects on offspring remain uncertain. The safety of other peroral antidiabetics in pregnancy is less studied. Advancements in glucose monitoring and insulin administration present encouraging prospects for enhancing outcomes in women with diabetes types 1 and 2. Both HDP and diabetes during pregnancy necessitate vigilant management through a combination of lifestyle modifications, pharmacological interventions, and timely obstetric care. Although certain treatments such as low-dose aspirin and metformin show efficacy in risk reduction, further research is ongoing to ensure safety for both mothers and their offspring to reduce short- and long-term adverse effects.

Neonatal outcome following metformin-treated gestational diabetes mellitus: A population-based cohort study

INTRODUCTION

Neonatal hypoglycemia is a common complication associated with gestational diabetes and therefore relevant to consider in evaluations of maternal treatment. We aimed to investigate the risk of neonatal hypoglycemia in offspring exposed to metformin treatment alone (MT) or combined with insulin (MIT) in comparison with nutrition therapy alone (NT), and insulin treatment alone (IT). In addition, we investigated MT in comparison with MIT. Secondary outcomes included neonatal anthropometrics, respiratory morbidity, hyperbilirubinemia, 5-min Apgar score, and preterm birth.

MATERIAL AND METHODS

This Swedish population-based cohort included 16 181 women diagnosed with gestational diabetes, and their singleton offspring born in 2019-2021. We estimated risk as adjusted odds ratio (aOR) with 95% confidence interval (CI), using individual-level, linkage register-data in multivariable logistic regression models.

RESULTS

In the main analysis, MT was associated with a lower risk of neonatal hypoglycemia vs NT (aOR 0.85, 95% CI: 0.74-0.96), vs MIT (0.74 [0.64-0.87]), and vs IT (0.47 [0.40-0.55]), whereas MIT was associated with a similar risk of neonatal hypoglycemia vs NT (1.14 [0.99-1.30]) and with lower risk vs IT (0.63 [0.53-0.75]). However, supplemental feeding rates were lower for NT vs pharmacological treatments (p < 0.001). In post hoc subgroup analyses including only exclusively breastfed offspring, the risk of neonatal hypoglycemia was modified and similar among MT and NT, and higher in MIT vs NT. Insulin exposure, alone or combined with metformin, was associated with increased risk of being large for gestational age. Compared with NT, exposure to any pharmacological treatment was associated with significantly lower risk of 5-min Apgar score < 4. All other secondary outcomes were comparable among the treatment categories.

CONCLUSIONS

The risk of neonatal hypoglycemia appears to be comparable among offspring exposed to single metformin treatment and nutrition therapy alone, and the lower risk that we observed in favor of metformin is probably explained by a difference in supplemental feeding practices rather than metformin per se. By contrast, the lower risk favoring metformin exposure over insulin exposure was not explained by supplemental feeding. However, further investigations are required to determine whether the difference is an effect of metformin per se or mediated by other external factors.

Safety of GLP-1 Receptor Agonists and Other Second-Line Antidiabetics in Early Pregnancy

Importance

Increasing use of second-line noninsulin antidiabetic medication (ADM) in pregnant individuals with type 2 diabetes (T2D) may result in fetal exposure, but their teratogenic risk is unknown.

Objective

To evaluate periconceptional use of second-line noninsulin ADMs and whether it is associated with increased risk of major congenital malformations (MCMs) in the infant.

Design, Setting, and Participants

This observational population-based cohort study used data from 4 Nordic countries (2009-2020), the US MarketScan Database (2012-2021), and the Israeli Maccabi Health Services database (2009-2020). Pregnant women with T2D were identified and their live-born infants were followed until up to 1 year after birth.

Exposure

Periconceptional exposure was defined as 1 or more prescription fill of sulfonylureas, dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide 1 (GLP-1) receptor agonists, and sodium-glucose cotransporter 2 (SGLT2) inhibitors, or insulin (active comparator) from 90 days before pregnancy to end of first trimester.

Main Outcomes and Measures

Relative risks (RRs) and 95% CIs for MCMs were estimated using log-binomial regression models, adjusting for key confounders in each cohort and meta-analyzed.

Results

Periconceptional exposure to second-line noninsulin ADMs differed between countries (32, 295, and 73 per 100 000 pregnancies in the Nordics, US, and Israel, respectively), and increased over the study period, especially in the US. The standardized prevalence of MCMs was 3.7% in all infants (n = 3 514 865), 5.3% in the infants born to women with T2D (n = 51 826), and among infants exposed to sulfonylureas was 9.7% (n = 1362); DPP-4 inhibitors, 6.1% (n = 687); GLP-1 receptor agonists, 8.3% (n = 938); SGLT2 inhibitors, 7.0% (n = 335); and insulin, 7.8% (n = 5078). Compared with insulin, adjusted RRs for MCMs were 1.18 (95% CI, 0.94-1.48), 0.83 (95% CI, 0.64-1.06), 0.95 (95% CI, 0.72-1.26), and 0.98 (95% CI, 0.65-1.46) for infants exposed to sulfonylureas, DPP-4 inhibitors, GLP-1 receptor agonists, and SGLT2 inhibitors, respectively.

Conclusions and Relevance

Use of second-line noninsulin ADMs is rapidly increasing for treatment of T2D and other indications, resulting in an increasing number of exposed pregnancies. Although some estimates were imprecise, results did not indicate a large increased risk of MCMs above the risk conferred by maternal T2D requiring second-line treatment. Although reassuring, confirmation from other studies is needed, and continuous monitoring will provide more precise estimates as data accumulate.

Achieving comparability in glycemic control between antidiabetic treatment strategies in pregnancy when using real world data

PURPOSE

Healthcare utilization databases often lack information on glycemic control, a key confounder when studying the safety of antidiabetic treatments, since patients with worse control are channeled to second-line agents, in particular insulin, versus first-line agents such as metformin. We evaluated whether adjustment for measured characteristics attains balance in glycemic control when comparing antidiabetic treatment strategies in pregnant women with pregestational type 2 diabetes (T2DM).

METHODS

In a US insurance claims database, we identified 3360 women with T2DM pregnant between 2004 and 2015, of whom a subset of 996 had data on hemoglobin A1c (HbA1c ) levels. We selected insulin only as the comparator group and used propensity score (PS)-matching on comorbidities and proxies of diabetes severity, but not on HbA1c , to adjust for confounding. We used standardized differences (st.diff) to assess balance in claims-based covariates and mean HbA1c (% ± SD) in the subset.

RESULTS

There were imbalances in claims-based covariates before PS-matching, with smaller differences when both treatment strategies included insulin. After PS-matching, balance was achieved in most claims-based covariates (st.diff <0.1). Mean HbA1c was similar before and after PS-matching when both treatments included insulin (e.g., 7.1 ± 1.5 vs. 7.7 ± 1.8 and 7.1 ± 1.5 vs. 7.5 ± 1.7, respectively, for metformin + insulin vs. insulin only). Differences in mean HbA1c remained after PS-matching when non-insulin treatments were compared to treatments including insulin (e.g., 6.3 ± 1.1 vs. 7.6 ± 1.7 for metformin only vs. insulin only).

CONCLUSIONS

Balance in both claims-based characteristics and glycemic control was attained after restricting the population to women with T2DM and comparing treatment strategies indicated for patients with similar diabetes severity. When comparing treatment strategies with versus without insulin, differences in glycemic control persisted after PS-matching even when balance was attained for other measured characteristics.

Patterns of Prescription Medication Use during the First Trimester of Pregnancy in the United States, 1997-2018

The objective of this analysis was to describe patterns of prescription medication use during pregnancy, including secular trends, with consideration of indication, and distributions of use within demographic subgroups. We conducted a descriptive secondary analysis using data from 9,755 women whose infants served as controls in two large United States case-control studies from 1997-2011 and 2014-2018. After excluding vitamin, herbal, mineral, vaccine, i.v. fluid, and topical products and over-the-counter medications, the proportion of women that reported taking at least one prescription medication in the first trimester increased over the study years, from 37% to 50% of women. The corresponding proportions increased with increasing maternal age and years of education, were highest for non-Hispanic White women (47%) and lowest for Hispanic women (24%). The most common indication for first trimester use of a medication was infection (12-15%). Increases were observed across the years for medications used for indications related to nausea/vomiting, depression/anxiety, infertility, thyroid disease, diabetes, and epilepsy. The largest relative increase in use among women was observed for medications to treat nausea/vomiting, which increased from 3.8% in the earliest years of the study (1997-2001) to 14.8% in 2014-2018, driven in large part by ondansetron use. Prescription medication use in the first trimester of pregnancy is common and increasing. Many medical conditions require treatments among pregnant women, often involving pharmacotherapy, which necessitates consideration of the risk and safety profiles for both mother and fetus.

Significant publications in diabetes pharmacotherapy and technology in 2020

INTRODUCTION

The most significant articles on diabetes pharmacotherapy and technology in the peer-reviewed literature from 2020, as determined by a panel of pharmacists with expertise in diabetes care and education, are summarized.

AREAS COVERED

Members of the Association of Diabetes Care and Education Specialists Pharmacy Community of Interest were selected to review articles published in prominent peer-reviewed journals in 2020 that most impacted diabetes pharmacotherapy and technology. A list of 37 nominated articles were compiled (22 in diabetes pharmacotherapy and 15 in diabetes technology). Based on discussion among the authors, the articles were ranked based on significant contribution, impact, and diversity to diabetes pharmacotherapy and technology. The top 10 highest ranked publications (n = 6 for diabetes pharmacotherapy and n = 4 in diabetes technology) are summarized in this article.

EXPERT OPINION

With the significant number of publications in diabetes care and education, it can be challenging and overwhelming to remain current with published literature. This review article may be helpful in identifying key articles in diabetes pharmacotherapy and technology from the year 2020.

Antidiabetic Medication Utilisation before and during Pregnancy in Switzerland between 2012 and 2019: An Administrative Claim Database from the MAMA Cohort

Background

The incidence of diabetes mellitus (both pregestational and gestational) is increasing worldwide, and hyperglycemia during pregnancy is associated with adverse pregnancy outcomes. Evidence on the safety and efficacy of metformin during pregnancy has accumulated resulting in an increase in its prescription in many reports.

Aims

We aimed to determine the prevalence of antidiabetic drug use (insulins and blood glucose-lowering drugs) before and during pregnancy in Switzerland and the changes therein during pregnancy and over time.

Methods

We conducted a descriptive study using Swiss health insurance claims (2012-2019). We established the MAMA cohort by identifying deliveries and estimating the last menstrual period. We identified claims for any antidiabetic medication (ADM), insulins, blood glucose-lowering drugs, and individual substances within each class. We defined three groups of pattern use based on timing of dispensation: (1) dispensation of at least one ADM in the prepregnancy period and in or after trimester 2 (T2) (pregestational diabetes); (2) dispensation for the first time in or after T2 (GDM); and (3) dispensation in the prepregnancy period and no dispensation in or after T2 (discontinuers). Within the pregestational diabetes group, we further defined continuers (dispensation for the same group of ADM) and switchers (different ADM group dispensed in the prepregnancy period and in or after T2).

Results

MAMA included 104,098 deliveries with a mean maternal age at delivery of 31.7. Antidiabetic dispensations among pregnancies with pregestational and gestational diabetes increased over time. Insulin was the most dispensed medication for both diseases. Between 2017 and 2019, less than 10% of pregnancies treated for pregestational diabetes continued metformin rather than switching to insulin. Metformin was offered to less than 2% of pregnancies to treat gestational diabetes (2017-2019).

Conclusion

Despite its position in the guidelines and the attractive alternative that metformin represents to patients who may encounter barriers with insulin therapy, there was reluctance to prescribe it.

Sex-specific effects of maternal metformin intervention during glucose-intolerant obese pregnancy on body composition and metabolic health in aged mouse offspring

AIMS/HYPOTHESIS

Metformin is increasingly used to treat gestational diabetes (GDM) and pregnancies complicated by pregestational type 2 diabetes or polycystic ovary syndrome but data regarding long-term offspring outcome are lacking in both human studies and animal models. Using a mouse model, this study investigated the effects of maternal metformin intervention during obese glucose-intolerant pregnancy on adiposity, hepatic steatosis and markers of metabolic health of male and female offspring up to the age of 12 months.

METHODS

C57BL/6J female mice were weaned onto either a control diet (Con) or, to induce pre-conception obesity, an obesogenic diet (Ob). The respective diets were maintained throughout pregnancy and lactation. These obese dams were then randomised to the untreated group or to receive 300 mg/kg oral metformin hydrochloride treatment (Ob-Met) daily during pregnancy. In male and female offspring, body weights and body composition were measured from 1 month until 12 months of age, when serum and tissues were collected for investigation of adipocyte cellularity (histology), adipose tissue inflammation (histology and quantitative RT-PCR), and hepatic steatosis and fibrosis (histochemistry and modified Folch assay).

RESULTS

At 12 months of age, male Ob and Ob-Met offspring showed increased adiposity, adipocyte hypertrophy, elevated expression of proinflammatory genes, hyperleptinaemia and hepatic lipid accumulation compared with Con offspring. Male Ob-Met offspring failed to show hyperplasia between 8 weeks and 12 months, indicative of restricted adipose tissue expansion, resulting in increased immune cell infiltration and ectopic lipid deposition. Female Ob offspring were relatively protected from these phenotypes but Ob-Met female offspring showed increased adiposity, adipose tissue inflammation, hepatic lipid accumulation, hyperleptinaemia and hyperinsulinaemia compared with Con female offspring.

CONCLUSIONS/INTERPRETATION

Maternal metformin treatment of obese dams increased offspring metabolic risk factors in a sex- and age-dependent manner. These observations highlight the importance of following up offspring of both sexes beyond early adulthood after interventions during pregnancy. Our findings illustrate the complexity of balancing short-term benefits to mother and child vs any potential long-term metabolic effects on the offspring when prescribing therapeutic agents that cross the placenta.

Metformin in pregnancy and risk of abnormal growth outcomes at birth: a register-based cohort study

We previously reported an increased risk of being small for gestational age (SGA) and a decreased risk of being large for gestational age (LGA) after in utero exposure to metformin compared with insulin exposure. This follow-up study investigated if these observations remain when metformin exposure (henceforth, metformin cohort) is compared with non-pharmacological antidiabetic treatment of gestational diabetes mellitus (GDM; naïve cohort), instead of insulin. RESEARCH DESIGN AND METHODS : This was a Finnish population register-based cohort study from singleton children born during 2004-2016. Birth outcomes from metformin cohort (n=3964) and the naïve cohort (n=82 675) were used in the main analyses. Additional analyses were conducted in a subcohort, restricting the metformin cohort to children of mothers with GDM only (n=2361). Results were reported as inverse probability of treatment weighted OR (wOR), with the naïve cohort as reference. RESULTS  : No difference was found for the outcome of SGA between the cohorts in the main analyses (wOR 0.97, 95% CI 0.73 to 1.27) or in the additional analyses (wOR 1.01, 95% CI 0.75 to 1.37). No difference between the cohorts was found for the risk of LGA (wOR 0.91, 95% CI 0.75 to 1.11) in the main analyses but a decreased risk was observed in the additional analyses (wOR 0.72, 95% CI 0.56 to 0.92). CONCLUSIONS : This follow-up study found no increase in the risk of SGA or LGA after in utero exposure to metformin, compared with drug-naïve GDM. The decreased risk of LGA in mothers with GDM may suggest residual confounding. The lack of increased SGA risk aligns with findings from studies using metformin in non-diabetic pregnancies. In contrast, lower birth weight and increased SGA birth risk were observed in GDM pregnancies for metformin versus insulin. Metformin should be avoided with emerging growth restriction in utero. The interplay of intrauterine hyperglycemia and pharmacological treatments needs further assessment.

Impact of pharmacological treatment of gestational diabetes on the mode of delivery and birth weight: a nationwide population-based study on a subset of singleton pregnant Portuguese women

AIMS

To access the impact of increasing use of metformin on cesarean section and large for gestational age rates, when compared to insulin.

METHODS

A retrospective observational study was developed using data from the Portuguese National Registry, between 2011 and 2019, of 5038 Portuguese women with single pregnancies and gestational diabetes treated with metformin and/or insulin. Three groups were defined according to the therapeutic regimen adopted: g1-insulin in monotherapy (n = 3027[60.1%]); g2-metformin in monotherapy (n = 1366[27.1%]); g3-metformin and insulin (n = 645[12.8%]). Multivariate analysis was adjusted for statistically significant covariates.

RESULTS

The cesarean section rate in g1 was similar to g2 (g1:36.9% vs. g2:37%, p = 0.982), although g3 was associated with cesarean delivery (g3:43.6% vs. g1:36.9%, p = 0.005; g3:43.6% vs. g1:37.0%, p = 0.002), with no differences reported in the multivariate analysis adjusted for year of delivery and pregestational body mass index. A delivery of a large for gestational age newborn was less frequently observed in g2 than in g1 (g2:4.1% vs. g1:5.4%, p = 0.044) and in g3 (g2:4.1% vs. g3:9.1%, p < 0.001), and in g1, when compared to g3 (g1:5.4% vs. g3:9.1%, p < 0.001). In the multivariate analysis, g2 showed lower odds of delivering a large for gestational age newborn, compared to g1 (β = -0.511, OR = 0.596, CI95% = 0.428-0.832, p < 0.001).

CONCLUSIONS

The use of metformin was not associated with higher cesarean section rates, compared to insulin. Instead, it was suggested a protective role of metformin on large gestational age rates. The concomitant use of dual therapy suggests more complex pregnancies, requiring closer surveillance that mitigate serious perinatal and obstetrical outcomes.

Maternal diabetes negatively impacts fetal health

Diabetes is a chronic metabolic disease affecting an increasing number of people. Although diabetes has negative health outcomes for diagnosed individuals, a population at particular risk are pregnant women, as diabetes impacts not only a pregnant woman's health but that of her child. In this review, we cover the current knowledge and unanswered questions on diabetes affecting an expectant mother, focusing on maternal and fetal outcomes.

Metformin in obese pregnancy has no adverse effects on cardiovascular risk in early childhood

Metformin is widely used in pregnancy, despite lack of long-term safety for children. We hypothesised that metformin exposure in utero is associated with increased cardiovascular risk. We tested this hypothesis in a follow-up study of children born to obese mothers who had participated in a randomised controlled trial of metformin versus placebo in pregnancy (EMPOWaR). We measured body composition, peripheral blood pressure (BP), arterial pulse wave velocity and central haemodynamics (central BP and augmentation index) using an oscillometric device in 40 children of mean (SD) age 5.78 (0.93) years, exposed to metformin (n = 19) or placebo (n = 21) in utero. There were no differences in any of the anthropometric or vascular measures between metformin and placebo-exposed groups in univariate analyses, or after adjustment for potential confounders including the child's behaviour, diet and activity levels. Post-hoc sample size calculation indicated we would have detected large clinically significant differences between the groups but would need an unfeasible large number to detect possible subtle differences in key cardiovascular risk parameters in children at this age of follow-up. Our findings suggest no evidence of increased cardiovascular risk in children born to obese mothers who took metformin in pregnancy and increase available knowledge of the long-term safety of metformin on childhood outcomes.

Metformin: Sex/Gender Differences in Its Uses and Effects—Narrative Review

Metformin (MTF) occupies a major and fundamental position in the therapeutic management of type 2 diabetes mellitus (T2DM). Gender differences in some effects and actions of MTF have been reported. Women are usually prescribed lower MTF doses compared to men and report more gastrointestinal side effects. The incidence of cardiovascular events in women on MTF has been found to be lower to that of men on MTF. Despite some promising results with MTF regarding pregnancy rates in women with PCOS, the management of gestational diabetes, cancer prevention or adjunctive cancer treatment and COVID-19, most robust meta-analyses have yet to confirm such beneficial effects.

The use of glucose-lowering medications for the treatment of type 2 diabetes mellitus during pregnancy in the United States

INTRODUCTION

Some guidelines allow for the use of either insulin or noninsulin antidiabetic agents for gestational diabetes, but only insulin is recommended for pregnant women with preexisting type 2 diabetes mellitus (T2DM). We aimed to document treatment patterns in routine care for women with preexisting T2DM.

METHODS

We identified pregnancy cohorts within 2 US claims databases for publicly and privately insured individuals: the Medicaid Analytical eXtract (2000-2014) and OptumClinformatics (2004-2014). T2DM was classified with a validated algorithm using ICD-9-CM and CPT codes. We assessed medication usage over the years of the study, and changes in medication use before and after the beginning of pregnancy, using prescription fills as a proxy for the use of insulin, metformin, sulphonylureas and other noninsulin antidiabetic agents before pregnancy and during each trimester.

RESULTS

Among 12,631 women with T2DM, insulin use in pregnancy was stable over the study years (55%-60% in the 2nd trimester), but 2nd trimester use of metformin increased from <5% to 20%. Over the study period, 41% of women filled a prescription for metformin before pregnancy, 37% in the 1st trimester and 17% in the 2nd trimester. By the 2nd trimester, few women used sulphonylureas (11%) or other noninsulin antidiabetic agents (1%). Of the women on metformin only before pregnancy, 36% switched to insulin only by 2nd trimester, 11% added insulin and 16% continued on metformin only. Of the women on metformin and insulin before pregnancy, 61% switched to insulin only by 2nd trimester, 22% continued with metformin and insulin and <5% used only metformin.

CONCLUSION

The use of insulin-metformin combinations and other noninsulin antidiabetic drugs during pregnancy has increased. Safety studies for these medication regimens are needed.

Controversies in Gestational Diabetes

Gestational diabetes mellitus (GDM) complicates approximately 7% of pregnancies in the USA. Despite recognition of the benefits of diagnosing and treating GDM, there are several areas of controversy that remain unresolved. There is debate as to whether to screen for GDM with the one-step versus the two-step approach. While the former identifies more pregnancies with potential adverse outcomes, data are lacking as to whether treatment of these pregnancies will improve outcomes, while increasing costs by diagnosing more women. Though it is well established that the diagnosis of even mild GDM, and treatment with lifestyle recommendations and insulin, improves pregnancy outcomes, it is controversial as to which type and regimen of insulin is optimal, and whether oral agents can be used safely and effectively to control glucose levels. Finally, it is recommended that women with GDM get tested for type 2 diabetes within several months of delivery; however, many women do not undergo this testing and alternative approaches are needed. These controversies are discussed with data from both sides of the debate to enable clinicians to make patient-centered decisions until more definitive data are available.

The role of socioeconomic factors on discontinuation of insulin during pregnancy—methodological challenges from a Swedish register-based study

Aim

Continuous use of antidiabetic medication, especially insulin, is crucial for diabetes management. In pregnancy, adherence to medication is generally low and may also be associated with lower socioeconomic status. However, little is known about discontinuation of insulin in pregnant women and the potential role of socioeconomic factors. Therefore, this study aims to measure the associations between socioeconomic factors and insulin discontinuation during pregnancy in women using insulin prior to the start of pregnancy in Sweden.

Subjects and methods

This cohort study identified pregnancies recorded in the Swedish Medical Birth Register from 2006 to 2016 in women receiving insulin prior to the start of pregnancy (N = 6029). Discontinuation of insulin was defined as not receiving a refill within 120 days from the previous refill. Associations between discontinuation and socioeconomic factors were investigated via logistic regression. Sensitivity analyses were performed using different definitions of discontinuation.

Results

Women discontinued insulin use in 34.2% of pregnancies. The odds ratios (ORs) of discontinuation of insulin were 1.17 [95% confidence interval (CI): 1.01–1.37] for women with lower household disposable incomes and 1.14 (95% CI: 1.01–1.29) for women with lower educational levels. When testing a change in the maximum refill gap from 91 days to 180 days, women with lower educational levels and those born in non-Nordic countries showed greater associations with discontinuation.

Conclusion

The definition of discontinuation affects the level of association of socioeconomic factors with discontinuation. Nevertheless, discontinuation of insulin is common in Sweden, especially in the lower socioeconomic groups. The socioeconomic inequality in insulin use behavior is worth noting.

Changing patterns in medication prescription for gestational diabetes during a time of guideline change in the USA: a cross-sectional study

OBJECTIVE

To define patterns of prescription and factors associated with choice of pharmacotherapy for gestational diabetes mellitus (GDM), namely metformin, glyburide and insulin, during a period of evolving professional guidelines.

DESING

Cross-sectional study.

SETTING

US commercial insurance beneficiaries from Market-Scan (late 2015 to 2018).

STUDY DESIGN

We included women with GDM, singleton gestations, 15-51 years of age on pharmacotherapy. The exposure was pharmacy claims for metformin, glyburide and insulin.

MAIN OUTCOMES

Pharmacotherapy for GDM with either oral agent, metformin or glyburide, compared with insulin as the reference, and secondarily, consequent treatment modification (addition and/or change) to metformin, glyburide or insulin.

RESULTS

Among 37 762 women with GDM, we analysed data from 10 407 (28%) with pharmacotherapy, 21% with metformin (n = 2147), 48% with glyburide (n = 4984) and 31% with insulin (n = 3276). From late 2015 to 2018, metformin use increased from 17 to 29%, as did insulin use from 26 to 44%, whereas glyburide use decreased from 58 to 27%. By 2018, insulin was the most common pharmacotherapy for GDM; metformin was more likely to be prescribed by 9% compared with late 2015/16, but glyburide was less likely by 45%. Treatment modification occurred in 20% of women prescribed metformin compared with 2% with insulin and 8% with glyburide.

CONCLUSIONS

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for GDM among a privately insured US population during a time of evolving professional guidelines. Further evaluation of the relative effectiveness and safety of metformin compared with insulin is needed.

TWEETABLE ABSTRACT

Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for gestational diabetes mellitus in the USA.

Metformin in pregnancy and risk of adverse long-term outcomes: a register-based cohort study

This study aimed to investigate if maternal pregnancy exposure to metformin is associated with increased risk of long-term and short-term adverse outcomes in the child. RESEARCH DESIGN AND METHODS : This register-based cohort study from Finland included singleton children born 2004-2016 with maternal pregnancy exposure to metformin or insulin (excluding maternal type 1 diabetes): metformin only (n=3967), insulin only (n=5273) and combination treatment (metformin and insulin; n=889). The primary outcomes were long-term offspring obesity, hypoglycemia, hyperglycemia, diabetes, hypertension, polycystic ovary syndrome, and challenges in motor-social development. In a sensitivity analysis, the primary outcomes were investigated only among children with maternal gestational diabetes. Secondary outcomes were adverse outcomes at birth. Analyses were conducted using inverse- probability of treatment weighting (IPTW), with insulin as reference. RESULTS  : Exposure to metformin or combination treatment versus insulin was not associated with increased risk of long-term outcomes in the main or sensitivity analyses. Among the secondary outcomes, increased risk of small for gestational age (SGA) was observed for metformin (IPTW-weighted OR 1.65, 95% CI 1.16 to 2.34); increased risk of large for gestational age, preterm birth and hypoglycemia was observed for combination treatment. No increased risk was observed for neonatal mortality, hyperglycemia, or major congenital anomalies. CONCLUSIONS : This study found no increased long-term risk associated with pregnancy exposure to metformin (alone or in combination with insulin), compared with insulin. The increased risk of SGA associated with metformin versus insulin suggests caution in pregnancies with at-risk fetal undernutrition. The increased risks of adverse outcomes at birth associated with combination treatment may reflect confounding by indication or severity.

Validation of a Claims-based Algorithm to Identify Pregestational Diabetes Among Pregnant Women in the United States

BACKGROUND

Identifying pregestational diabetes in pregnant women using administrative claims databases is important for studies of the safety of antidiabetic treatment in pregnancy, but limited data are available on the validity of case-identifying algorithms. The purpose of this study was to evaluate the validity of an administrative claims-based algorithm to identify pregestational diabetes.

METHODS

Using a cohort of pregnant women nested within the Medicaid Analytic Extract (MAX) database, we developed an algorithm to identify pregestational type 1 and type 2 diabetes, distinct from gestational diabetes. Within a single large healthcare system in the Boston area, we identified women who delivered an infant between 2000 and 2010 and were covered by Medicaid, and linked their electronic health records to their Medicaid claims within MAX. Medical records were reviewed by two physicians blinded to the algorithm classification to confirm or rule out pregestational diabetes, with disagreements resolved by discussion. We calculated positive predictive values with 95% confidence intervals using the medical record as the reference standard.

RESULTS

We identified 49 pregnancies classified by the claims-based algorithm as pregestational diabetes that were linked to the electronic health records and had records available for review. The PPV for any pregestational diabetes was 92% [95% confidence interval (CI) 82%, 97%], type 2 diabetes 87% (68%, 95%), and type 1 diabetes 57% (37%, 75%).

CONCLUSIONS

The claims-based algorithm for pregestational diabetes and type 2 diabetes performed well; however, the PPV was low for type 1 diabetes.

Metformin for gestational diabetes study: metformin vs insulin in gestational diabetes: glycemic control and obstetrical and perinatal outcomes: randomized prospective trial

BACKGROUND

Gestational diabetes that is not properly controlled with diet has been commonly treated with insulin. In recent years, several studies have published that metformin can lead to, at least, similar obstetrical and perinatal outcomes as insulin. Nevertheless, not all clinical guidelines endorse its use, and clinical practice is heterogeneous.

OBJECTIVE

This study aimed to test whether metformin could achieve the same glycemic control as insulin and similar obstetrical and perinatal results, with a good safety profile, in women with gestational diabetes that is not properly controlled with lifestyle changes.

STUDY DESIGN

The metformin for gestational diabetes study was a multicenter, open-label, parallel arms, randomized clinical trial performed at 2 hospitals in Málaga (Spain), enrolling women with gestational diabetes who needed pharmacologic treatment. Women at the age of 18 to 45 years, in the second or third trimesters of pregnancy, were randomized to receive metformin or insulin (detemir or aspart). The main outcomes were (1) glycemic control (mean glycemia, preprandial and postprandial) and hypoglycemic episodes and (2) obstetrical and perinatal outcomes and complications (hypertensive disorders, type of labor, prematurity, macrosomia, large for gestational age, neonatal care unit admissions, respiratory distress syndrome, hypoglycemia, jaundice). Outcomes were analyzed on an intention-to-treat basis.

RESULTS

Between October 2016 and June 2019, 200 women were randomized, 100 to the insulin-treated group and 100 to the metformin-treated group. Mean fasting and postprandial glycemia did not differ between groups, but postprandial glycemia was significantly better after lunch or dinner in the metformin-treated-group. Hypoglycemic episodes were significantly more common in the insulin-treated group (55.9% vs 17.7% on metformin; odds ratio, 6.118; 95% confidence interval, 3.134-11.944; P=.000). Women treated with metformin gained less weight from the enrollment to the prepartum visit (36-37 gestational weeks) (1.35±3.21 vs 3.87±3.50 kg; P=.000). Labor inductions (45.7% [metformin] vs 62.5% [insulin]; odds ratio, 0.506; 95% confidence interval, 0.283-0.903; P=.029) and cesarean deliveries (27.6% [metformin] vs 52.6% [insulin]; odds ratio, 0.345; 95% confidence interval, 0.187-0.625; P=.001) were significantly lower in the metformin-treated group. Mean birthweight, macrosomia, and large for gestational age and babies' complications were not different between treatment groups. The lower cesarean delivery rate for women treated with metformin was not associated with macrosomia, large or small for gestational age, or other complications of pregnancy.

CONCLUSION

Metformin treatment was associated with a better postprandial glycemic control than insulin for some meals, a lower risk of hypoglycemic episodes, less maternal weight gain, and a low rate of failure as an isolated treatment. Most obstetrical and perinatal outcomes were similar between groups.

The efficacy and safety of metformin alone or as an add-on therapy to insulin in pregnancy with GDM or T2DM: A systematic review and meta-analysis of 21 randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Pregnant women are increasingly being exposed to metformin for conditions including gestational diabetes mellitus and type 2 diabetes mellitus. Metformin has been found to exhibit maternal to foetal transfer, and the long-term influence is uncertain. We conducted a meta-analysis to compare the efficacy and safety of metformin alone or as add-on therapy to insulin and insulin in pregnancy with gestational diabetes mellitus or type 2 diabetes mellitus.

METHODS

We performed a comprehensive literature search of PubMed, Embase, Cochrane Library and ClinicalTrials.gov for randomized controlled trials (RCTs) that compared metformin to insulin in pregnancy. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were used to synthesize the results. Two authors independently extracted the data, evaluated study quality and calculated pooled estimates.

RESULTS

Twenty-one studies involving 4,545 patients were included in this meta-analysis. Compared with insulin, metformin significantly reduced the risks of maternal weight gain [MD -1.51 kg, 95%CI (-1.90 kg, -1.12 kg), P < 0.00001], gestational age at birth [MD -0.12 week, 95%CI (-0.21 week, -0.02 week), P = 0.02], gestational hypertension [RR 0.63, 95%CI (0.48, 0.82), P = 0.0006], maternal hypoglycaemia [RR 0.33, 95%CI (0.15, 0.73), P = 0.006], birthweight [MD -0.13 kg, 95%CI (-0.20 kg, -0.07 kg), P < 0.0001], neonatal hypoglycaemia [RR 0.56, 95%CI (0.49, 0.64), P < 0.00001], neonatal intensive care unit admission [RR 0.73, 95%CI (0.64, 0.83), P < 0.00001], birthweight ≥4000 g [RR 0.70, 95%CI (0.59, 0.83), P < 0.0001], and large for gestational age [RR 0.83, 95%CI (0.72, 0.97), P = 0.02] and significantly increased the risk of small for gestational age [RR 1.43, 95%CI (1.08, 1.89), P = 0.01] in pregnancy.

WHAT IS NEW AND CONCLUSION

Metformin may have potential benefits for pregnant women and newborns in terms of maternal and foetal outcomes. More studies with long-term follow-up of offspring exposed to metformin in utero are needed to provide evidence for the future use of metformin in pregnancy.

Maternal Metformin Intervention during Obese Glucose-Intolerant Pregnancy Affects Adiposity in Young Adult Mouse Offspring in a Sex-Specific Manner

Background: Metformin is commonly used to treat gestational diabetes mellitus. This study investigated the effect of maternal metformin intervention during obese glucose-intolerant pregnancy on the gonadal white adipose tissue (WAT) of 8-week-old male and female mouse offspring. Methods: C57BL/6J female mice were provided with a control (Con) or obesogenic diet (Ob) to induce pre-conception obesity. Half the obese dams were treated orally with 300 mg/kg/d of metformin (Ob-Met) during pregnancy. Gonadal WAT depots from 8-week-old offspring were investigated for adipocyte size, macrophage infiltration and mRNA expression of pro-inflammatory genes using RT-PCR. Results: Gestational metformin attenuated the adiposity in obese dams and increased the gestation length without correcting the offspring in utero growth restriction and catch-up growth caused by maternal obesity. Despite similar body weight, the Ob and Ob-Met offspring of both sexes showed adipocyte hypertrophy in young adulthood. Male Ob-Met offspring had increased WAT depot weight (p < 0.05), exaggerated adipocyte hyperplasia (p < 0.05 vs. Con and Ob offspring), increased macrophage infiltration measured via histology (p < 0.05) and the mRNA expression of F4/80 (p < 0.05). These changes were not observed in female Ob-Met offspring. Conclusions: Maternal metformin intervention during obese pregnancy causes excessive adiposity, adipocyte hyperplasia and WAT inflammation in male offspring, highlighting sex-specific effects of prenatal metformin exposure on offspring WAT.

Could Subtle Obstetrical Brachial Plexus Palsy Be Related to Unilateral B Glenoid Osteoarthritis?

Background: Several factors associated with B glenoid are also linked with obstetrical brachial plexus palsy (OBPP). The purpose of this observational study was to determine the incidence of OBPP risk factors in type B patients. Methods: A cohort of 154 patients (68% men, 187 shoulders) aged 63 ± 17 years with type B glenoids completed a questionnaire comprising history of perinatal characteristics related to OBPP. A literature review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to estimate the incidence of OBPP risk factors in the general population. Results: Twenty-seven patients (18%) reported one or more perinatal OBPP risk factors, including shoulder dystocia (n = 4, 2.6%), macrosomia >4 kg (n = 5, 3.2%), breech delivery (n = 6, 3.9%), fetal distress (n = 8, 5.2%), maternal diabetes (n = 2, 1.3%), clavicular fracture (n = 2, 1.3%), and forceps delivery (n = 4, 2.6%). The comparison with the recent literature suggested that most perinatal OBPP risk factors were within the normal range, although the incidence of shoulder dystocia, forceps and vaginal breech deliveries exceeded the average rates. Conclusion: Perinatal factors related to OBPP did not occur in a higher frequency in patients with Walch type B OA compared to the general population, although some of them were in the high normal range.

Trends and associated maternal characteristics of antidiabetic medication use among pregnant women in South Korea

The prevalence of diabetes during pregnancy and the need for the treatment are increasing. We aimed to investigate antidiabetic medications (ADM) use among pregnant women and their characteristics. Using Korea’s nationwide healthcare database, we included women aged 15–49 years with births during 2004–2013. The prevalence and secular trend of ADM use were assessed in 3 periods: pre-conception period, first trimester, and second/third trimesters. To compare maternal characteristics between pregnancies with and without ADM prescription, we used the χ² or Fisher’s exact test and Cochran-Armitage trend test. The prescription patterns analyzed by calendar year, age, insurance type, income, area, and medical institution. Of 81,559 pregnancies, 222 (0.27%) and 305 (0.37%) were exposed ADM during pre-conception and pregnancy periods, respectively. ADM prescriptions increased significantly by an 11.3-fold in second/third trimesters, while a 2.9-fold in first trimester. ADM use is more prevalent in women aged older and living in urban areas. Metformin was most used in the pre-conception period, while insulins were most during pregnancy. About 0.4% of women received ADM during pregnancy; a rate was lower than that in western countries. Non-recommended medications were more common in first trimester, which warrants pregnancy screening for women taking ADM.

The Current and Potential Therapeutic Use of Metformin-The Good Old Drug

Metformin, one of the oldest oral antidiabetic agents and still recommended by almost all current guidelines as the first-line treatment for type 2 diabetes mellitus (T2DM), has become the medication with steadily increasing potential therapeutic indications. A broad spectrum of experimental and clinical studies showed that metformin has a pleiotropic activity and favorable effect in different pathological conditions, including prediabetes, type 1 diabetes mellitus (T1DM) and gestational diabetes mellitus (GDM). Moreover, there are numerous studies, meta-analyses and population studies indicating that metformin is safe and well tolerated and may be associated with cardioprotective and nephroprotective effect. Recently, it has also been reported in some studies, but not all, that metformin, besides improvement of glucose homeostasis, may possibly reduce the risk of cancer development, inhibit the incidence of neurodegenerative disease and prolong the lifespan. This paper presents some arguments supporting the initiation of metformin in patients with newly diagnosed T2DM, especially those without cardiovascular risk factors or without established cardiovascular disease or advanced kidney insufficiency at the time of new guidelines favoring new drugs with pleotropic effects complimentary to glucose control. Moreover, it focuses on the potential beneficial effects of metformin in patients with T2DM and coexisting chronic diseases.

Mental health and its associations with glucose-lowering medication in women with gestational diabetes mellitus. A prospective clinical cohort study

AIMS

Mental health symptoms are frequent in women with gestational diabetes mellitus (GDM) and may influence glycemic control. We therefore investigated if mental health symptoms (high depression and low well-being scores) predicted a need for glucose-lowering medication and if this use of medication influenced the trajectory of mental health during pregnancy and in the postpartum period.

METHODS

We included 341 pregnant women from a cohort of GDM women in a Swiss University Hospital. The World Health Organization Well-being Index-Five was collected at the first and last GDM and at the postpartum clinical visits and the Edinburgh Postnatal Depression Scale at the first GDM and the postpartum clinical visits. Medication intake was extracted from participants' medical records. We conducted linear and logistic regressions with depression as an interaction factor.

RESULTS

Mental health symptoms did not predict a need for medication (all p ≥ 0.29). Mental health improved over time (both p ≤ 0.001) and use of medication did not predict this change (all p ≥ 0.40). In women with symptoms of depression, medication was associated with less improvement in well-being at the postpartum clinical visit (p for interaction=0.013).

CONCLUSIONS

Mental health and glucose-lowering medication did not influence each other in an unfavourable way in this cohort of women with GDM.

Improvement Effect of Metformin on Female and Male Reproduction in Endocrine Pathologies and Its Mechanisms

Metformin (MF), a first-line drug to treat type 2 diabetes mellitus (T2DM), alone and in combination with other drugs, restores the ovarian function in women with polycystic ovary syndrome (PCOS) and improves fetal development, pregnancy outcomes and offspring health in gestational diabetes mellitus (GDM) and T2DM. MF treatment is demonstrated to improve the efficiency of in vitro fertilization and is considered a supplementary drug in assisted reproductive technologies. MF administration shows positive effect on steroidogenesis and spermatogenesis in men with metabolic disorders, thus MF treatment indicates prospective use for improvement of male reproductive functions and fertility. MF lacks teratogenic effects and has positive health effect in newborns. The review is focused on use of MF therapy for restoration of female and male reproductive functions and improvement of pregnancy outcomes in metabolic and endocrine disorders. The mechanisms of MF action are discussed, including normalization of metabolic and hormonal status in PCOS, GDM, T2DM and metabolic syndrome and restoration of functional activity and hormonal regulation of the gonadal axis.

Metformin in women with type 2 diabetes in pregnancy (MiTy): a multicentre, international, randomised, placebo-controlled trial

BACKGROUND

Although metformin is increasingly being used in women with type 2 diabetes during pregnancy, little data exist on the benefits and harms of metformin use on pregnancy outcomes in these women. We aimed to investigate the effects of the addition of metformin to a standard regimen of insulin on neonatal morbidity and mortality in pregnant women with type 2 diabetes.

METHODS

In this prospective, multicentre, international, randomised, parallel, double-masked, placebo-controlled trial, women with type 2 diabetes during pregnancy were randomly assigned from 25 centres in Canada and four in Australia to receive either metformin 1000 mg twice daily or placebo, added to insulin. Randomisation was done via a web-based computerised randomisation service and stratified by centre and pre-pregnancy BMI (<30 kg/m² or ≥30 kg/m²) in a ratio of 1:1 using random block sizes of 4 and 6. Women were eligible if they had type 2 diabetes, were on insulin, had a singleton viable pregnancy, and were between 6 and 22 weeks plus 6 days' gestation. Participants were asked to check their fasting blood glucose level before the first meal of the day, before the last meal of the day, and 2 h after each meal. Insulin doses were adjusted aiming for identical glucose targets (fasting glucose <5·3 mmol/L [95 mg/dL], 2-h postprandial glucose <6·7 mmol/L [120 mg/dL]). Study visits were done monthly and patients were seen every 1-4 weeks as was needed for standard clinical care. At study visits blood pressure and bodyweight were measured; patients were asked about tolerance to their pills, any hospitalisations, insulin doses, and severe hypoglycaemia events; and glucometer readings were downloaded to the central coordinating centre. Participants, caregivers, and outcome assessors were masked to the intervention. The primary outcome was a composite of fetal and neonatal outcomes, for which we calculated the relative risk and 95% CI between groups, stratifying by site and BMI using a log-binomial regression model with an intention-to-treat analysis. Secondary outcomes included several relevant maternal and neonatal outcomes. The trial was registered with ClinicalTrials.gov, NCT01353391.

FINDINGS

Between May 25, 2011, and Oct 11, 2018, we randomly assigned 502 women, 253 (50%) to metformin and 249 (50%) to placebo. Complete data were available for 233 (92%) participants in the metformin group and 240 (96%) in the placebo group for the primary outcome. We found no significant difference in the primary composite neonatal outcome between the two groups (40% vs 40%; p=0·86; relative risk [RR] 1·02 [0·83 to 1·26]). Compared with women in the placebo group, metformin-treated women achieved better glycaemic control (HbA_1c at 34 weeks' gestation 41·0 mmol/mol [SD 8·5] vs 43·2 mmol/mol [-10]; 5·90% vs 6·10%; p=0·015; mean glucose 6·05 [0·93] vs 6·27 [0·90]; difference -0·2 [-0·4 to 0·0]), required less insulin (1·1 units per kg per day vs 1·5 units per kg per day; difference -0·4 [95% CI -0·5 to -0·2]; p<0·0001), gained less weight (7·2 kg vs 9·0 kg; difference -1·8 [-2·7 to -0·9]; p<0·0001) and had fewer caesarean births (125 [53%] of 234 in the metformin group vs 148 [63%] of 236 in the placebo group; relative risk [RR] 0·85 [95% CI 0·73 to 0·99]; p=0·031). We found no significant difference between the groups in hypertensive disorders (55 [23%] in the metformin group vs 56 [23%] in the placebo group; p=0·93; RR 0·99 [0·72 to 1·35]). Compared with those in the placebo group, metformin-exposed infants weighed less (mean birthweight 3156 g [SD 742] vs 3375 g [742]; difference -218 [-353 to -82]; p=0·002), fewer were above the 97th centile for birthweight (20 [9%] in the metformin group vs 34 [15%] in the placebo group; RR 0·58 [0·34 to 0·97]; p=0·041), fewer weighed 4000 g or more at birth (28 [12%] in the metformin group vs 44 [19%] in the placebo group; RR 0·65 [0·43 to 0·99]; p=0·046), and metformin-exposed infants had reduced adiposity measures (mean sum of skinfolds 16·0 mm [SD 5·0] vs 17·4 [6·2] mm; difference -1·41 [-2·6 to -0·2]; p=0·024; mean neonatal fat mass 13·2 [SD 6·2] vs 14·6 [5·0]; p=0·017). 30 (13%) infants in the metformin group and 15 (7%) in the placebo group were small for gestational age (RR 1·96 [1·10 to 3·64]; p=0·026). We found no significant difference in the cord c-peptide between groups (673 pmol/L [435] in the metformin group vs 758 pmol/L [595] in the placebo group; p=0·10; ratio of means 0·88 [0·72 to 1·02]). The most common adverse event reported was gastrointestinal (38 events in the metformin group and 38 events in the placebo group).

INTERPRETATION

We found several maternal glycaemic and neonatal adiposity benefits in the metformin group. Along with reduced maternal weight gain and insulin dosage and improved glycaemic control, the lower adiposity and infant size measurements resulted in fewer large infants but a higher proportion of small-for-gestational-age infants. Understanding the implications of these effects on infants will be important to properly advise patients who are contemplating the use of metformin during pregnancy.

FUNDING

Canadian Institutes of Health Research, Lunenfeld-Tanenbaum Research Institute, University of Toronto.

Metformin versus insulin use for treatment of gestational diabetes and delivery by caesarean section: A nationwide Swedish cohort study

OBJECTIVE

Pregnant women who develop gestational diabetes (GDM) are more likely to deliver by caesarean section (CS). Over the last decade, the use of metformin has increased as an alternative to insulin but it's unknown how this shift in treatment has influenced the mode of delivery. Therefore, the aim of this study was to determine the association between metformin use and CS and delivery of a large-for-gestational age (LGA) infant compared to insulin use for GDM.

STUDY DESIGN

The Swedish population health registers were linked to identify pregnant women from 2012 to 2016 without preexisting diabetes and with a first filled prescription of insulin or metformin in trimester 2 or 3 (n = 2467), categorized into those treated with insulin only (88%), metformin only (7.6%), or both insulin and metformin (4.3%). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Analyses were adjusted for relevant covariates and stratified by history of CS.

RESULTS

The proportion of women using metformin to treat GDM increased from 2.5% in 2012 to over 30% in 2016. Comparing insulin only to metformin only use, no association with delivery by CS (adjusted OR 0.79, 95% CI; 0.54-1.16) and lower odds of delivering a LGA infant (adjusted OR 0.44, 95% CI; 0.26-0.76) was found. Treatment with both insulin and metformin was associated with an increased risk of CS (adjusted OR 1.65, 95% CI; 1.06-2.56), which were more often unplanned. Estimates were further elevated in nulliparous (adjusted OR 2.32, 95% CI; 0.95-5.65) and multiparous women with a history of CS (adjusted OR 2.29, 95% CI; 0.60-8.74) but conclusions could not be drawn given the wide CIs.

CONCLUSION

There was no evidence of a higher association of metformin use alone with CS compared to insulin use for treatment of GDM but a protective effect for delivery of a LGA infant was shown. Women requiring treatment with both insulin and metformin had increased odds for delivery by CS which in turn may indicate that the need for the use of both medications to treat GDM suggests a pregnancy at higher risk.