Background: Many clinical trials have reported that low-dose aspirin decreases the risk of pre-eclampsia in women with prior pre-eclampsia. However, its impact in a real-world population has not been fully assessed.
Objectives: To assess the rates of low-dose aspirin initiation during pregnancy in women with a history of pre-eclampsia, and to evaluate the impact of low-dose aspirin in prevention of pre-eclampsia recurrence in a real-world population.
Study design: CONCEPTION is a French nationwide cohort study which uses data from the country’s National Health Data System database. We included all women in France who gave birth at least twice between 2010-2018, and who had pre-eclampsia during their first pregnancy. Every dispensing of low-dose aspirin (75-300 mg) between the beginning of their second pregnancy and 36 weeks of gestation (WG) was identified. We used Poisson regression models to estimate the adjusted incidence rate ratios (aIRRs) of receiving aspirin at least once during their second pregnancy. In women who had early and/or severe pre-eclampsia during their first pregnancy, we estimated the IRRs of pre-eclampsia recurrence during their second pregnancy according to the aspirin therapy.
Results: In 28,467 women who were included in the study, the aspirin initiation rate during the second pregnancy ranged from 27.8% for women in whose first pregnancy the pre-eclampsia was mild and late, to 79.9% for those women whose pre-eclampsia was severe and early. Just over half (54.3%) of those treated with aspirin-initiated treatment before 16 WG and adhered to treatment. Compared with women with mild and late pre-eclampsia, the aIRRs (95% CI) for receiving aspirin at least once during the second pregnancy were 1.94 (1.86-2.03) for women with severe and late pre-eclampsia, 2.34 (2.17-2.52) for those with early and mild pre-eclampsia, and 2.87 [2.74-3.01] for those with early and severe pre-eclampsia E. Social deprivation was associated with a lower initiation of aspirin (IRR = 0.74 [0.70-0.78]). Aspirin was not associated with a lower risk of mild and late pre-eclampsia, severe and late pre-eclampsia, or mild and early pre-eclampsia during the second pregnancy. The aIRRs for severe and early pre-eclampsia during the second pregnancy were 0.77 (0.62-0.95) for women who received prescribed aspirin at least once, 0.71 (0.5-0.89) for those who initiated aspirin therapy before 16 WG, and 0.60 (0.47-0.77) for those who adhered to aspirin treatment throughout their second pregnancy. The risk of severe and early pre-eclampsia was lower only when the prescribed mean daily dose was ≥ 100 mg/day.
Conclusion: In women with a history of pre-eclampsia, aspirin initiation during a second pregnancy and adherence to the prescribed dosage were largely insufficient, especially for women experiencing social deprivation. Aspirin initiated before 16 WG at a dose ≥ 100 mg/day was associated with a lower risk of severe and early pre-eclampsia.