The question of the optimal Aspirin Dose Preeclampsia prophylaxis remains a key debate in obstetric medicine. A new randomized controlled trial (RCT) investigated whether 162 mg of aspirin daily offers superior efficacy compared to the standard 81 mg dose for preventing preterm preeclampsia or preeclampsia with severe features. This investigation involved high-risk pregnant individuals. The study aimed to provide clear evidence on dosing, which varies across global clinical guidelines.
Trial Findings on Aspirin Dose Preeclampsia Efficacy
The pragmatic, randomized, open-label trial enrolled 400 high-risk participants before 16 weeks of gestation. Researchers randomized them to receive either 162 mg or 81 mg of aspirin daily until term. Ultimately, the primary composite outcome—preterm preeclampsia or preeclampsia with severe features—occurred in 14.1% (26 of 184) of the 162-mg group. Consequently, this rate compared closely with 17.1% (31 of 181) in the 81-mg group. The difference was not statistically significant (relative risk 0.83, 95% CI, 0.51–1.33, P=.4).
Furthermore, individual outcomes, including preterm preeclampsia and term preeclampsia with severe features, showed similar incidence rates between the dosage groups. Adherence to therapy also remained comparable. Rates ranged from 88% to 91% for the higher dose group and 89% to 92% for the lower dose group across study visits. Therefore, the trial concluded that treatment with either 81 mg or 162 mg of aspirin before 16 weeks of gestation resulted in similar rates of the primary composite outcome among high-risk people.
Safety Considerations and Existing Guidelines
While the primary outcome was similar, the trial reported notable differences in secondary safety outcomes. For example, the 162-mg group had eight cases of placental abruption, but the 81-mg group had zero (P=.013). Moreover, singleton birth weight was slightly lower in the 162-mg group (2.9 kg vs 3.2 kg, P=.005). These safety signals warrant careful consideration before adopting the higher dose as a standard treatment.
In contrast to this study, a prior systematic review and meta-analysis suggested that a dosage of 150 mg to 162 mg daily might be associated with a lower risk of preterm preeclampsia than 75 mg to 81 mg daily. However, international guidelines remain varied. For instance, the Samrakshan program in India for high-risk women recommends a daily dose of 150 mg. Conversely, the US-based ACOG guidelines generally recommend 81 mg/day for prophylaxis. Clearly, this new RCT reinforces the need for clinicians to weigh efficacy, side-effect profile, and local guidelines when deciding on aspirin prophylaxis.
Frequently Asked Questions
Q1: What was the primary conclusion of the trial regarding aspirin dosage for preeclampsia?
The trial concluded that the rates of preterm preeclampsia or preeclampsia with severe features were similar for high-risk pregnant people randomized to either 81 mg or 162 mg of aspirin daily, suggesting no significant difference in efficacy.
Q2: Were there any safety differences found between the 81 mg and 162 mg aspirin groups?
Yes, the 162-mg group had eight reported cases of placental abruption, compared to zero cases in the 81-mg group. Additionally, the average singleton birth weight was slightly lower in the 162-mg group (2.9 kg vs 3.2 kg).
Q3: How do the trial results compare to current practice recommendations in India?
While the trial did not show superior efficacy for 162 mg, evidence-based programs in India, such as Samrakshan, have been recommending a higher dose of 150 mg daily for high-risk women, based on international data like the ASPRE trial. Clinicians must consider these local guidelines alongside the new data.
References
- Khander A et al. Comparison of 162 mg and 81 mg Aspirin for Prevention of Preeclampsia: A Randomized Controlled Trial. Obstet Gynecol. 2026 Jan 01. doi: 10.1097/AOG.0000000000006100. PMID: 41296512.
- Ghesquiere L, Guerby P, Marchant I, et al. Comparing aspirin 75 to 81 mg vs 150 to 162 mg for prevention of preterm preeclampsia: systematic review and meta-analysis. Am J Obstet Gynecol MFM. 2023;5(10):101098.
- Kumar B, Aggarwal D, Sharma U. Compliance with Low-Dose Aspirin and Outcomes in High-Risk Pregnant Women in Guna District of Central India. J Obstet Gynaecol India. 2023;73(4):307–313.
- USPSTF Final Recommendation Statement: Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality. US Preventive Services Task Force. Published September 28, 2021.