In utero aspirin exposure and child neurocognitive development: A propensity score-matched analysis.

Objective: To evaluate the association between a short-period, high-dose in utero aspirin exposure and child neurocognitive development.

Design: A propensity score-matched analysis of a multicentre prospective cohort study.

Setting: The US Collaborative Perinatal Project (1959-1976).

Population: A total of 50 565 singleton live births with maternal information.

Methods: We performed a propensity score matching to balance maternal characteristics between women with and without aspirin exposure. Inverse probability-weighted marginal structural models were used to estimate associations between aspirin exposure and child neurocognitive assessments.

Main outcome measures: Child neurocognitive development was assessed using the Bayley Scales at 8 months, the Stanford Binet Intelligence Scale at 4 years, and the Wechsler Intelligence Scale and Wide-Range Achievement Test (WRAT) at 7 years.

Results: Children exposed to aspirin in utero were associated with an 8%-16% reduced risk of having suspect/abnormal or below-average scores in most neurocognitive assessments. A trend of lower risks of having suspect/abnormal or below-average scores was further observed in children with in utero aspirin exposure for more than 7 days, particularly on Bayley Mental (relative risk [RR] 0.82, 95% CI 0.74-0.92), WRAT Reading (RR 0.88, 95% CI 0.78-0.98) and WRAT Arithmetic tests (RR 0.76, 95% CI 0.66-0.86). This association was mainly observed in the second trimester of pregnancy.

Conclusions: In utero aspirin exposure was associated with improved child neurocognitive development in a prospective cohort study. Further studies are warranted to evaluate the impact of long-period and low-dose in utero aspirin exposure on child short- and long-term neurodevelopment.