Neonatal outcomes in gestational diabetes mellitus: metformin alone versus metformin with insulin: a retrospective cohort study in India

Dharshan G. B.; Rahul S. Rao; Vijaya Shambhavi B.; Shreya D. P.; Bharathi K. R.; Varsha I. Dalal

doi:10.18203/2320-1770.ijrcog20263417

Authors

Dharshan G. B. Department of Pharmacy Practice, PES Institute of Pharmacy, Bengaluru, Karnataka, India https://orcid.org/0009-0000-0598-481X
Rahul S. Rao Department of Pharmacy Practice, PES Institute of Pharmacy, Bengaluru, Karnataka, India https://orcid.org/0009-0002-8127-4320
Vijaya Shambhavi B. Department of Pharmacy Practice, PES Institute of Pharmacy, Bengaluru, Karnataka, India
Shreya D. P. Department of Pharmacy Practice, PES Institute of Pharmacy, Bengaluru, Karnataka, India
Bharathi K. R. Department of Obstetrics and Gynaecology, PESU Institute of Medical Sciences and Research, Bengaluru, Karnataka India
Varsha I. Dalal Department of Obstetrics and Gynaecology, PESU Institute of Medical Sciences and Research, Bengaluru, Karnataka India

DOI:

https://doi.org/10.18203/2320-1770.ijrcog20263417

Keywords:

Metformin, Insulin, Gestational diabetes mellitus, Neonatal outcomes, NICU admission, Birth weight

Abstract

Background: Gestational diabetes mellitus (GDM) is associated with adverse neonatal outcomes, including increased neonatal intensive care unit (NICU) admissions and differences in birth weight. Although metformin is commonly used for glycemic control in GDM, some patients require adjunctive insulin therapy. Comparative data on neonatal outcomes between these regimens remain inadequate.

Methods: This retrospective cohort study was conducted at a tertiary care center in Bengaluru, India. Medical records of women with singleton GDM pregnancies were analyzed and categorized into two groups: metformin monotherapy and metformin plus insulin. Primary outcomes were NICU admission and neonatal birth weight. Logistic regression was utilized to determine predictors of NICU admission, and linear regression estimated determinants of birth weight.

Results: Among 123 GDM pregnancies, 52.8% received metformin alone and 47.2% received combination therapy. NICU admissions were significantly lower in the metformin group compared to the combination group (46.2% versus. 74.1%, p=0.002). After adjusting for gestational age, metformin monotherapy was associated with reduced odds of NICU admission (OR=0.41, p=0.032), though maternal HbA1C emerged as the strongest predictor (AUC=0.751). When both HbA1C and birth weight were included in the model, treatment regimen lost statistical significance (p=0.056). Neonatal birth weight was significantly lower in the combination group (mean difference -0.30 kg), with gestational age showing a stronger association (0.151 kg/week, p<0.001).

Conclusions: Although NICU admissions were lower in the metformin monotherapy group, maternal glycemic control particularly HbA1C appears to be the principal determinant of neonatal outcomes in GDM pregnancies.

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