Aspirin use during pregnancy and hypoxia-related placental pathology

Abstract

Objective: Aspirin has been shown to prevent preeclampsia. But the mechanisms remain unclear despite that improved placental circulation is considered as an underlying contributor. Our aim was to examine the hypoxia-related morphological and histopathological placental measures in relation to aspirin use during pregnancy.

Study design: We used the Collaborative Perinatal Project (CPP) data, which is a cohort study conducted in the U.S. from 1959 to 1976. A total of 23, 604 women who had information on placental pathology and aspirin intake during pregnancy were included in the analysis. Among them, 1474 women had a history of hypertension or preeclampsia/eclampsia and were classified as a high-risk population; the rest were considered as a low-risk population. 47 placenta measures considered to be relevant to hypoxia were selected to build a composite hypoxia- related placenta index. The generalized linear mixed model was used to fit the relationship between aspirin and placental pathology.

Main outcome measures: Hypoxia-related placental pathology.

Results: Aspirin use during pregnancy was associated with a reduced risk of hypoxia-related placental pathology in the high-risk population [the adjusted odds ratio and 95% confidence interval in the 1st, 2nd, and 3rd trimesters: 0.55 (0.31, 1.00), 0.76 (0.49, 1.17), and 0.53 (0.29, 0.94), respectively]. Longer duration of aspirin use in pregnancy tended to have a lower risk of hypoxia-related placental pathologies in the high-risk population.

Conclusions: Aspirin use during pregnancy reduced risks of hypoxia-related placental pathologies in the high-risk women for preeclampsia. The duration of aspirin use determined its effects.

Keywords: Aspirin; Cohort study; Hypoxia; Placental pathology; Preeclampsia.