Disproportionate body composition and perinatal outcome in large-for-gestational-age infants to mothers with type 1 diabetes

Objective To determine if disproportionate body composition is a risk factor for perinatal complications in large-for-gestational-age infants born to mothers with type 1 diabetes. Design Population-based cohort study. Setting Data from the Swedish Medical Birth Registry from 1998 to 2007. Population National cohort of 3517 infants born to mothers with type 1 diabetes. Only singletons with gestational age 32-43 weeks were included. Methods Large for gestational age (LGA) was defined as birthweight > 90th centile and appropriate for gestational age (AGA) as birthweight between 10th and 90th centiles. Disproportionate (D) infants were defined as having a ponderal index [PI: calculated as birthweight in grams/(length in cm) 3 > 90th centile] and proportionate (P) as PI <= 90th centile. LGA infants were classified as P-LGA or D-LGA. Odds ratios were calculated for D-LGA and P-LGA infants, with AGA infants as the reference category. Odds ratios were adjusted for mode of delivery, fetal distress and stratified by gestational age. Main outcome measures The primary outcome was a composite of neonatal morbidities, i. e. any of the following diagnoses: Apgar score < 7 at 5 minutes, birth trauma (Erb's palsy or clavicle fracture), respiratory disorder, hyperbilirubinaemia or hypoglycaemia requiring treatment. Results Composite morbidity was significantly more frequent in LGA as opposed to AGA infants, but there was no difference in risk between P-LGA and D-LGA infants. Conclusions High birthweight, irrespective of body proportionality, is a risk factor for neonatal complications in offspring of women with type 1 diabetes.