Effects of maternal environmental tobacco smoke exposure during pregnancy on neurodevelopment of one-year-old rural infants in Yunnan province: a cohort study

Abstract

ObjectiveTo study the effect of maternal environmental tobacco smoke (ETS) exposure during pregnancy on the neurodevelopment of one-year-old rural infants in Yunnan province. MethodsA total of 385 newborns born between 2018 and 2019 in rural Xuanwei, Yunnan province, were recruited into a cohort and followed until 1 year of age. Ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine urinary cotinine (UC) concentrations in samples collected from the mothers of the newborns in early, mid, and late pregnancy to assess maternal ETS exposure during pregnancy. The Bayley Scales of Infant and Toddler Development – Third Edition (BSID-III) was used to assess infant neurodevelopment. Multiple linear regression and logistic regression models were constructed to analyze the effect of ETS exposure during pregnancy on infant neurodevelopment. ResultsThe mean UC levels (median [25th percentile, 75th percentile] ng/mL) of the 385 mothers in early, mid, and late pregnancy were 2.94 (0.66, 6.28), 2.86 (0.58, 5.85), and 2.50 (0.39, 5.78), respectively, and ETS exposure in early, mid, and late pregnancy was reported by 80.26%, 81.04%, and 80.00% of the mothers, respectively. For the infants at 1 year of age, the BSID-III dimensional development scores were 99.17 ± 17.57 for cognition, 93.46 ± 15.44 for language, 93.66 ± 15.83 for motor, 109.03 ± 22.36 for social-emotional, and 87.83 ± 15.67 for adaptive behavior, with 9.35%, 22.60%, 18.44%, 6.49%, and 29.35% of the infants assessed having scores indicating delayed five-dimensional development. The results of the multiple linear regression analysis showed that maternal ETS exposure in early pregnancy was negatively correlated with BSID-III motor score in 1-year-old infants (β = – 0.239, 95% confidence interval [95%CI]: – 0.454, – 0.025). The results of logistic regression analysis showed that maternal ETS exposure in early pregnancy may increase the risk of delayed language development in 1-year-old infants (odds ratio = 3.497, 95%CI: 1.186, 10.309). ConclusionMaternal ETS exposure during early pregnancy may affect infant neurodevelopment one year after birth, particularly motor and language development.

Keywords

• pregnancy
• environmental tobacco smoke
• infant
• neurodevelopment