Bahado–Singh RO et al. – The magnitude of the reduction of a newborn’s birth weight centile and neonatal fat mass related to the treatment of mild GDM appears greater for male neonates.

• This is a secondary analysis of a masked RCT of treatment for mild GDM. Outcomes included preeclampsia or gestational hypertension, birth weight, neonatal fat mass, and composite adverse outcomes for both neonate (preterm birth, SGA or NICU admission) and mother (labor induction, cesarean delivery, preeclampsia or gestational hypertension).
• After stratification according to fetal gender, the interaction of gender with treatment status was estimated for these outcomes.

• Of 469 pregnancies with male fetuses, 244 were randomized to treatment and 225 to routine care.
• For those with female fetuses, these numbers were 463, 233 and 230 respectively.
• The interaction of gender with treatment status was significant for fat mass (p=0.04) and birthweight centile (p = 0.02).
• Among women who were assigned to the treatment group, male offspring were significantly more likely to have both a lower birth weight centile (50.7 ± 29.2 vs 62.5 ± 30.2 centile, p < 0.0001) and less neonatal fat mass (487 ± 229.6 vs. 416.6 ± 172.8 g , p = 0.0005) whereas these differences were not significant among female offspring.
• There was no interaction between fetal gender and treatment group with regard to other outcomes.