High-dose aspirin prevents pre-eclampsia in high-risk women

The use of high-dose aspirin was associated with a significantly lower risk of developing pre-eclampsia compared with low-dose aspirin in women at risk for pre-eclampsia, with no increase in bleeding risk, according to a recent study.

“Numerous studies have evaluated the efficacy and safety of low-dose aspirin [81 or 150 mg] for pre-eclampsia prevention in high-risk women … [However,] there is limited data from the US evaluating aspirin 162 mg,” said lead author Dr Mariam Ayyash from the Henry Ford Health System (HFHS) in Detroit, Michigan, US.

Using data from the HFHS between 2013 and 2022, the researchers conducted a retrospective cohort study involving 3,597 pregnant women who were at high risk for pre-eclampsia. Of these, 387 women had been given high-dose aspirin (162 mg/day) and 994 women were given low-dose aspirin (81 mg/day) during their pregnancy, while the remaining 2,266 women did not receive any treatment. [SMFM 2021, abstract 788]

Women treated with high-dose aspirin had a significantly lower risk of pre-eclampsia than those treated with low-dose aspirin (10.1 percent vs 14.2 percent; p=0.043).

The risk of post-partum haemorrhage was comparable between the high-dose and low-dose aspirin groups (8.0 percent vs 6.3 percent; p=0.245), as was neonatal intraventricular haemorrhage (1.8 percent vs 2.9 percent; p=0.226).

Other outcomes, such as foetal growth restriction (23.3 percent vs 24.5 percent), birth weight (2,751 vs 2,726 grams), and preterm birth (30.0 vs 34.4 weeks), were also comparable between the high-dose and low-dose aspirin groups, except for neonatal intensive care unit admission that was less common among infants of women on high-dose vs low-dose aspirin (22.1 percent vs 27.6 percent; p=0.028).

Interestingly, the rates of pre-eclampsia were similar between those who received low-dose aspirin and those who did not receive aspirin (14.2 percent for both).

This finding is similar to that of a recent study from China which also showed that treatment with low-dose aspirin (100 mg) did not reduce the incidence of pre-eclampsia in high-risk pregnant women. [Am J Obstet Gynecol 2022;226:251.e1-251.e12]

“In women at high-risk for pre-eclampsia, prophylaxis with [high-dose] aspirin 162 mg decreased the rate of pre-eclampsia by approximately 30 percent compared with [those on low-dose] aspirin 81 mg or no aspirin prophylaxis, without an increased risk for bleeding,” Ayyash said.

“Our study demonstrates that aspirin 162 mg should be recommended for pre-eclampsia prophylaxis in high-risk women. Further studies by other groups are needed to confirm these findings,” she noted.