The effects of maternal obesity on perinatal outcomes among those born small for gestational age

Maternal obesity has been associated with higher birth weight. Small for gestational age (SGA) neonates born to obese women may be associated with pathological growth with increased neonatal complications.

This was a retrospective cohort study of all non-anomalous singleton neonates born in Texas from 2006-2011. Analyses were limited to births between 34 and 42 weeks gestation with birth weight ≤10th percentile. Results were stratified by maternal pre-pregnancy BMI class. The risk for stillbirth, neonatal death, neonatal intensive care unit (NICU) admission and five minute Apgar scores <7 were estimated for each obesity class and compared to the normal weight group. Multivariable logistic regression analyses were performed to control for potential confounding variables.

The rate of stillbirth was 1.4/1000 births for normal weight women, and 2.9/1000 among obese women (p < 0.001, aOR: 1.83 [1.43, 2.34]). The rate of neonatal deaths among normal weight women was 4.3/1000 births, whereas among obese women it was 4.7/1000 (p = 0.94, aOR: 1.10 [0.92, 1.30]). A dose-dependent relationship between maternal obesity and stillbirths was seen, but not for other neonatal outcomes.

Among SGA neonates, maternal pre-pregnancy obesity was associated with increased risks for stillbirth, NICU admission and low Apgar scores but not neonatal death.