Maternal obesity and development of the preterm newborn at 2 years.

Objective: To evaluate to what extent extremely preterm children (<28 weeks' gestational age) of overweight (BMI 25-29) or obese (BMI ≥30) women are at increased risk of adverse development at 2 years measured with the Bayley Scales of Infant Development II in a multicenter prospective cohort study.

Methods: Heights and prepregnancy weights of the mothers of 852 preterm born children were collected and included in multinomial logistic regression models.

Results: Compared to newborns born to mothers with normal BMIs, newborns of obese mothers, but not those of overweight mothers, were more likely to have Bayley Scales indices more than 3 standard deviations below the reference mean (mental: OR = 2.1; 95% CI: 1.3, 3.5) (motor: OR = 1.7; 95% CI: 1.1, 2.7). These associations were even more prominent in children who did not have the intermittent or sustained systemic inflammation profile previously shown to be associated with severely impaired development (mental: OR = 4.6; 95% CI: 1.6, 14) (motor: OR = 3.7; 95% CI: 1.5, 8.9).

Conclusions: Maternal obesity is associated with an increased risk of impaired offspring development. Some of this impaired development cannot be attributed to confounding due to immaturity, socio-economic correlates or neonatal systemic inflammation.