Perinatal smoking in mothers and fathers: Longitudinal associations with infant birth outcomes in the Triple B Pregnancy Cohort Study.

Abstract

Maternal smoking in pregnancy is a risk factor for poorer infant health outcomes, yet knowledge on impacts of smoking in the preconception and periconception periods is limited, particularly in fathers. This study examined the association between parental smoking at preconception, periconception and across pregnancy, with infant birth outcomes. Pregnant women and fathers from the longitudinal Triple B Pregnancy Cohort Study (1582 mothers; 805 fathers) were assessed across the perinatal period, and infants assessed at birth. Maternal and paternal smoking was assessed at preconception (3 months pre-pregnancy), periconception (prior to pregnancy awareness), and during pregnancy (trimesters 1-3). Infant birth outcomes included low birth weight, prematurity, small head circumference, small-for-gestational age (SGA), and neonatal intensive care unit (NICU) and/or special care nursery (SCN) admission. Maternal preconception and periconception smoking were associated with higher odds of NICU/SCN admission (aOR = 1·74; aOR = 1·80, respectively). Periconception smoking was associated with higher odds of prematurity (aOR = 2·05). Smoking across pregnancy was associated with higher odds of low birth weight (aOR = 2·77-3·53), prematurity (aOR = 2·79-3·78), SGA (aOR = 2.52-2·76), and admission to NICU/SCN (aOR = 2·21-2·40). Limited evidence was found for associations between maternal smoking and small head circumference, and for associations between perinatal smoking in fathers and adverse infant outcomes. Findings underscore the importance of smoking cessation support for parents prior to, and during the early weeks of pregnancy, to reduce the impacts of smoking on families.