Pregnancy smoking ups retinopathy of prematurity risk

Very preterm infants born to mothers who smoked during pregnancy are at a heightened risk of retinopathy of prematurity (ROP), a recent study has found.

Researchers conducted a retrospective, case-control analysis of 751 very preterm infants (≤32 weeks gestation), in whom ROP was screened through successive dilated eye exams until the retina was fully vascularized. Data on risk factors, including maternal smoking, Apgar score, and medications, were obtained from clinical records.

A total of 397 infants were deemed to have ROP, of whom 81 were identified as having a severe condition (stage ≥3). Sixty-three (8.3 percent) mothers reported smoking during pregnancy, consuming a median of 10 cigarettes per day.

The frequency distribution of ROP stages differed significantly when infants were classified according to their mothers’ smoking status during pregnancy (p=0.0115). In particular, stage ≥3 (22 percent vs 10 percent) and stage 2 (24 percent vs 20 percent) ROP occurred more frequently in neonates born to smoking mothers.

Multivariate binary logistic regression analysis further confirmed that smoking during pregnancy is a significant correlate of developing severe ROP, increasing its likelihood by more than twice (odds ratio, 2.591, 95 percent confidence interval, 1.097–6.122; p=0.03).

Other associated factors included total respiratory hour, which had a slight but significant impact per additional hour, and gestational age and birth weight, both of which were protective against severe ROP as they increased.