Nicotine Exposure During Pregnancy and Postnatal Cognitive Outcomes: A Systematic Review and Meta‐Analysis

AIM: Nicotine exposure during pregnancy interferes with critical periods of foetal brain development, disrupting the timing and functioning of neurodevelopment. This systematic review and meta-analysis aims to evaluate the effect of prenatal nicotine exposure on postnatal cognitive outcomes. METHODS: Web of Science, PubMed, PsycINFOand OpenGrey databases were searched, with no date restrictions. Human (k = 1) and animal research (k = 8) was included. Studies were required to include at least one postnatal cognitive measure during the pre-weaning period. RESULTS: Exposure to nicotine during pregnancy negatively impacted postnatal outcomes of spatial memory (Cohen's d = -1.117; 95% CI [-2.112, -0.123]), centre exploration in animal studies (d = -1.054; 95% CI [-1.659, -0.449]), and reflex development in human and animal studies (d = -1.126; 95% CI [-1.737, -0.514]). Prenatal nicotine exposure did not have a significant effect on ambulation (d = -0.044; 95% CI [0.485, 0.397]) and rearing (d = -0.45; 95% CI [-1.042, 0.142]) in animals. CONCLUSION: Findings suggest that certain domains may be especially vulnerable to prenatal nicotine exposure, with reflex development showing the strongest effect. The scarcity of human studies underscores an urgent need for further research to ensure informed recommendations on nicotine intake during pregnancy.