Alvarez‐Iglesias, Alberto

OBJECTIVE To assess whether initiating metformin at 25 weeks' gestation influences exclusive breastfeeding at 12 weeks postpartum in gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS We performed a prespecified secondary analysis of the Effectiveness of Metformin in Addition to Usual Care in the Reduction of Gestational Diabetes Effects (EMERGE) trial, a multicenter, double-blind, placebo-controlled randomized study. A total of 535 pregnant women (510 with newly diagnosed GDM) were allocated 1:1 to metformin (titrated to 2.5 g/day) or placebo alongside usual care. Infant feeding was prospectively documented at birth and at 4 and 12 weeks postpartum. The primary outcome was exclusive breastfeeding at 12 weeks (intention to treat). Multivariable logistic regression adjusted for race, education, smoking, booking BMI, health care access markers, and diagnostic oral glucose tolerance test (OGTT) glucose levels. RESULTS Twelve-week feeding data were available for 476 pregnancies (236 in the metformin group and 240 in the placebo group). Exclusive breastfeeding at 12 weeks was 27% with metformin and 26% with placebo (absolute difference +1.3%; 95% CI –6.3 to 8.7; P = 0.75). The adjusted odds ratio (OR) for metformin versus placebo was 1.24 (95% CI 0.79–1.96; P = 0.36). Feeding patterns shifted from breastfeeding to formula temporally in both groups (P < 0.001), with no treatment-by-time interaction (P = 0.61). Non-Caucasian ethnicity independently predicted exclusive breastfeeding (adjusted OR 2.37; 95% CI 1.27–4.42). CONCLUSIONS Starting metformin treatment at 25 weeks in the GDM group was not associated with differences in exclusive breastfeeding at 12 weeks postpartum. Where metformin was discontinued at delivery, the results support compatibility of antenatal metformin with breastfeeding objectives. Breastfeeding outcomes were more linked to sociodemographic factors than metabolic ones, highlighting the need for culturally appropriate postpartum support.

Abstract Background Pregnancies complicated by gestational diabetes mellitus (GDM) are associated with increased risks of adverse perinatal outcomes, and with long-term metabolic and cardiovascular consequences for both mother and child. The original EMERGE randomized controlled trial (RCT) evaluated the effectiveness of early metformin in addition to usual care in women with GDM on glycaemic control and perinatal outcomes. The EMERGE Mothers and Kids study is a longitudinal follow-up of the EMERGE trial participants, designed to investigate the long-term metabolic, cardiovascular, and neurodevelopmental outcomes in mothers and their offspring. Methods This is a prospective, observational cohort study of participants and their children from the EMERGE trial (NCT06327191). A single follow-up visit will be conducted up to 6 years after the index pregnancy. Maternal assessments include anthropometric data, glucose tolerance, and metabolic parameters. Child assessments include growth metrics, adiposity measured via skinfold thickness, and neurodevelopmental status assessed through validated questionnaires. Additional data on quality of life, mental health, breastfeeding, and health economics will also be collected. Discussion This study aims to provide insights into the long-term safety and efficacy of metformin use during pregnancy and its potential impact on the long term maternal and child health outcomes, contributing to evidence-based management of GDM. Trial registration: ClinicalTrials.gov; Identifier: NCT06327191

Abstract Aims To investigate the cost‐effectiveness of early initiation of metformin and usual care for gestational diabetes mellitus (GDM). Methods Economic evaluation from a healthcare perspective, based on the EMERGE randomised controlled trial. In total, 535 women with GDM were randomised to placebo in addition to usual care or metformin in addition to usual care. Economic outcomes included incremental healthcare costs and quality adjusted life years ( QALYs ) and expected cost‐effectiveness at cost‐effectiveness threshold values of €20,000, €45,000 and €100,000 per QALY gained. Uncertainty was explored using parametric, non‐parametric, deterministic and probabilistic methods and heterogeneity using subgroup analysis. Results On average, relative to the placebo arm, the early metformin arm was associated with non‐statistically significant mean increases of €193.07 (95% CI : −€789.88, €1176.01; p = 0.700) and 0.002 QALYs (95% CI : −0.009, 0.013; p = 0.771). In terms of expected cost‐effectiveness at threshold values of €20,000, €45,000 and €100,000 per QALY gained, the probability of the early metformin arm being more cost‐effective was estimated at 0.423, 0.452 and 0.524. Exploratory subgroup analyses provided more favourable but not definitive evidence in favour of the early metformin arm for cohorts with previous GDM and previous caesarean section. Conclusions We do not find definitive evidence that early initiation of metformin in addition to usual care for GDM was more cost‐effective than usual care alone. The clinical and economic evidence may be considered equivocal, but worthy of further examination.

Abstract Aim Women with gestational diabetes mellitus (GDM) display adverse lifetime cardiometabolic health. We examined whether early metformin in GDM could impact cardiometabolic risk factors postpartum. Methods EMERGE, a double-blind, placebo-controlled trial, randomized pregnancies 1:1 to placebo or metformin at GDM diagnosis and followed participants from randomization until 12 ± 4 weeks postpartum. In total, 478 pregnancies were available for postpartum maternal assessment, 237 and 241 assigned to metformin and placebo respectively. Weight (kg), body mass index (BMI) (kg/m2), waist circumference (cm), and blood pressure (mmHg) were measured, infant feeding method documented, and blood specimens drawn for a 75-gram oral glucose tolerance test, fasting insulin, C-peptide, and lipid analysis. Results Despite similar weight and BMI at trial randomization, participants receiving metformin had significantly lower weight (79.5 ± 15.9 vs 82.6 ± 16.9 kg; P = .04) and BMI (29.3 [5.6] vs 30.5 [5.4]; P = .018) at the postpartum visit. However, no difference in weight change from randomization to 12 weeks postpartum was observed between metformin and placebo groups. Overall, 29% (n = 139) of the cohort met criteria for prediabetes or diabetes, with no positive impact with metformin. There were also no differences in measurements of insulin resistance, blood pressure, or lipids between groups. Conclusion Early metformin use in GDM did not impact important cardiometabolic parameters in the early postpartum period despite significant benefits in weight gain and insulin use in pregnancy.

Importance Gestational diabetes is a common complication of pregnancy and the optimal management is uncertain. Objective To test whether early initiation of metformin reduces insulin initiation or improves fasting hyperglycemia at gestation weeks 32 or 38. Design, Setting, and Participants Double-blind, placebo-controlled trial conducted in 2 centers in Ireland (one tertiary hospital and one smaller regional hospital). Participants were enrolled from June 2017 through September 2022 and followed up until 12 weeks’ postpartum. Participants comprised 510 individuals (535 pregnancies) diagnosed with gestational diabetes based on World Health Organization 2013 criteria. Interventions Randomized 1:1 to either placebo or metformin (maximum dose, 2500 mg) in addition to usual care. Main Outcomes And Measures The primary outcome was a composite of insulin initiation or a fasting glucose level of 5.1 mmol/L or greater at gestation weeks 32 or 38. Results Among 510 participants (mean age, 34.3 years), 535 pregnancies were randomized. The primary composite outcome was not significantly different between groups and occurred in 150 pregnancies (56.8%) in the metformin group and 167 pregnancies (63.7%) in the placebo group (between-group difference, −6.9% [95% CI, −15.1% to 1.4%]; relative risk, 0.89 [95% CI, 0.78-1.02]; P = .13). Of 6 prespecified secondary maternal outcomes, 3 favored the metformin group, including time to insulin initiation, self-reported capillary glycemic control, and gestational weight gain. Secondary neonatal outcomes differed by group, with smaller neonates (lower mean birth weights, a lower proportion weighing >4 kg, a lower proportion in the >90% percentile, and smaller crown-heel length) in the metformin group without differences in neonatal intensive care needs, respiratory distress requiring respiratory support, jaundice requiring phototherapy, major congenital anomalies, neonatal hypoglycemia, or proportion with 5-minute Apgar scores less than 7. Conclusion and relevance Early treatment with metformin was not superior to placebo for the composite primary outcome. Prespecified secondary outcome data support further investigation of metformin in larger clinical trials. Trial Registration ClinicalTrials.gov Identifier: NCT02980276 ; EudraCT: 2016-001644-19