Low-Dose Aspirin for Preeclampsia Prevention in Twin Pregnancies
Women with twin pregnancies should receive low-dose aspirin (81 mg/day) for preeclampsia prevention starting between 12-16 weeks of gestation and continuing until delivery, as they are considered a high-risk group according to current guidelines. 1, 2
Risk Stratification for Preeclampsia
Twin pregnancies are classified as a high-risk factor for preeclampsia development according to the American College of Obstetricians and Gynecologists (ACOG) and the U.S. Preventive Services Task Force (USPSTF) guidelines. The USPSTF specifically identifies multifetal gestation as one of the high-risk factors that warrant prophylactic low-dose aspirin therapy 3, 1.
High-Risk Factors for Preeclampsia:
- Twin/multifetal gestation
- History of preeclampsia
- Chronic hypertension
- Type 1 or 2 diabetes
- Renal disease
- Autoimmune disease 1, 2
Timing and Dosage
- Initiation: Low-dose aspirin should be started between 12-16 weeks of gestation (optimally before 16 weeks)
- Dosage: 81 mg daily
- Duration: Continue until delivery 1, 2
The timing of initiation is critical, as starting before 16 weeks appears to be more effective in preventing preeclampsia due to its influence on placentation 1.
Effectiveness in Twin Pregnancies
The evidence regarding aspirin's effectiveness specifically in twin pregnancies shows mixed results:
A 2021 observational study found that low-dose aspirin (100 mg daily) significantly reduced the risk of preeclampsia (RR 0.48; 95% CI 0.24-0.95) and preterm birth <34 weeks (RR 0.50; 95% CI 0.29-0.86) in twin pregnancies 4.
However, a 2022 real-world study found no significant reduction in preeclampsia with low-dose aspirin in twin pregnancies, possibly due to poor compliance with aspirin use 5.
A 2023 study identified twin pregnancies as having one of the highest risks of developing preeclampsia even while using prophylactic aspirin (ARR:2.62,95% CI: 1.68-4.11), suggesting that while aspirin is recommended, these pregnancies still require careful monitoring 6.
Dosage Considerations
Recent evidence suggests that higher doses (>100 mg daily) initiated before 16 weeks may be more effective at reducing preeclampsia risk 7. However, the current ACOG and USPSTF guidelines still recommend 81 mg daily as the standard dose 1, 2.
Safety Profile
Low-dose aspirin in pregnancy has a well-established safety record with minimal risk of maternal or fetal complications. Studies have shown that the risk of postpartum hemorrhage is not significantly increased with low-dose aspirin use (RR 0.89; 95% CI 0.35-2.26) 4.
Monitoring Recommendations
Women with twin pregnancies should be monitored closely throughout pregnancy, even when taking prophylactic aspirin, as they remain at elevated risk for preeclampsia despite preventive measures 6.
Key Points for Implementation
- Identify twin pregnancies early in prenatal care
- Initiate low-dose aspirin between 12-16 weeks of gestation
- Continue daily 81 mg aspirin until delivery
- Maintain vigilant monitoring for signs of preeclampsia throughout pregnancy
- Ensure patient education about the importance of medication adherence
Despite prophylactic aspirin use, twin pregnancies remain at higher risk for preeclampsia compared to other high-risk categories, requiring heightened clinical vigilance throughout pregnancy 6.