Background
Gestational diabetes mellitus is associated with an increased risk of neonatal respiratory distress. The Treatment of Booking Gestational Diabetes Mellitus (TOBOGM) multicenter randomized controlled trial of treating early gestational diabetes mellitus (eGDM) showed a reduction in the incidence of neonatal respiratory distress. The mechanisms behind this improvement remain unclear. The aim of this study was to identify clinical factors associated with neonatal respiratory distress among those with eGDM.
Study Design
This was a secondary analysis from TOBOGM. Pregnant women with GDM risk factors completed an oral glucose tolerance test (OGTT) before 20 weeks’ gestation and those with eGDM based on WHO 2013 criteria were randomized to either immediate (eGDM-IRX) or deferred GDM treatment (eGDM-DRX). Neonatal respiratory distress (NRD) was defined as warranting ≥4 hours of respiratory support with supplemental oxygen or supported ventilation during the 24 hours after birth. Respiratory Distress Syndrome (RDS) was defined as NRD with admission to neonatal nursery admission for ≥24 hours with positive pressure ventilatory support for ≥4 hours. Stepwise logistic regression was used to compare pregnancies with and without NRD and then, among those with NRD, to compare those with and without neonatal nursery admission for up to 24 hours with those with admission for over 24 hours. Group comparisons were adjusted for seven prespecified factors: age, pre-pregnancy BMI, ethnicity, current smoking, primigravity, university degree or higher qualifications and for site. Adjusted Odds Ratio with 95% confidence intervals are shown.
Results
Overall, 99/793 (12.5%) were affected by NRD. RDS was present in 7/400 (1.8%) of eGDM-IRX and 8/393 (2.0%) eGDM-DRX (p=ns). NRD was half (0.50, 0.31-0.79) as likely if GDM treatment was started early. NRD was also associated with Caesarean section (2.31, 1.42 to 3.76) being a large for gestational age baby (1.83, 1.09 to 3.08), induction of labor (1.77, 1.07 to 2.91) and shorter pregnancy duration (0.95, 0.93 to 0.97 per day). Among infants with NRD, having a stay of >24 hours in a neonatal nursery, was associated with a higher 1-hour glucose on the early OGTT (1.38, 1.08 to 1.76 per mmol/l).
Conclusions
The NRD risk after eGDM is reduced by treatment. Nursery admission with NRD is more likely with higher 1-hour glucose on OGTT. Further studies are needed to understand the mechanisms behind this early GDM complication and its long-term effects.