Maternal smoking during pregnancy and long-term neurological morbidity of the offspring

Abstract

Objective: To evaluate the long-term pediatric neurological morbidity of children born to mothers who reported smoking during pregnancy as compared with children born to non-smoking mothers.

Study design: A population-based cohort analysis was performed comparing all deliveries of mothers who reported smoking during pregnancy and non-smoking mothers between 1991 and 2014 at a single tertiary medical center. Hospitalizations of the offspring up to the age of 18 years involving neurological morbidities were evaluated according to a predefined set of ICD-9 codes, including autism, development and movement disorders, cerebral palsy and more. A Kaplan-Meier survival curve was used to compare cumulative hospitalization rate in exposed and unexposed offspring and a Cox proportional hazards model was used to control for confounders.

Results: During the study period, 242,342 deliveries met the inclusion criteria. Of them, 2861 (1.2%) were children of smoking mothers. Neurological-related hospitalizations were significantly higher in children born to smoking mothers, as compared with the non-smoking group (5.3% vs. 3.1%, p < 0.01). Specifically, these children had higher rates of movement, eating and developmental disorders as well as attention deficit hyperactive disorder. The Kaplan-Meier survival curve demonstrated a significant higher cumulative incidence of neurological-related hospitalizations in the smoking group (log rank p < 0.01). Using a Cox proportional hazards model, controlling for potential confounders, maternal tobacco use was found to be independently associated with long-term neurological morbidity of the offspring (adjusted HR = 1.58, CI 1.33-1.89, p value < 0.01).

Conclusion: Maternal smoking during pregnancy is an independent risk factor for long-term neurological morbidity of the offspring.

Keywords: Follow up; Hospitalization; Long term; Neurological morbidity; Pregnancy; Smoking.