Association of intrauterine exposure to aspirin and blood pressure at 7 years of age: a secondary analysis

Objective: To examine whether maternal aspirin use during pregnancy is associated with childhood blood pressure.

Design/setting: A secondary analysis of the Collaborative Perinatal Project, a prospective cohort study including 12 US academic medical centres between 1959 and 1976.

Population: Singleton births among women with detailed medication information.

Methods: We carried out linear and multivariate logistic regression analysis to assess the associations between maternal aspirin exposure and childhood blood pressure at age 7 years.

Main outcome measures: Offspring blood pressure at age 7 years.

Results: A total of 15 793 women were exposed to aspirin 4 weeks before the last menstrual period or during pregnancy. In utero aspirin exposure may be associated with an 11% (95% CI 0.85- 0.93) and a 20% (95% CI 0.76-0.84) reduced risk of having high systolic blood pressure (SBP) and diastolic blood pressure (DBP) at 7 years of age, and a mean decrease of 0.62 mmHg for SBP and 1.04 mmHg for DBP at 7 years of age. Compared with children born to mothers without aspirin exposure, those whose mothers were exposed to aspirin for at least 7 days during pregnancy had approximately 10% and 27% reduced risk of high SBP and DBP, respectively, and a mean reduction of 0.61 and 1.27 mmHg in SBP and DBP at 7 years of age. The earlier the aspirin exposure occurred during pregnancy, the lower the risk of childhood high blood pressure.

Conclusion: In utero exposure to aspirin may have long-term benefits for childhood blood pressure.

Tweetable abstract: Maternal aspirin exposure might decrease the risk of childhood blood pressure.