Low-Dose Aspirin Prophylaxis in Pregnant Women with Type 1 and Type 2 Diabetes
Pregnant individuals with type 1 or type 2 diabetes should be prescribed low-dose aspirin 100–150 mg/day starting at 12 to 16 weeks of gestation to lower the risk of preeclampsia. 1
Rationale and Evidence
- Diabetes in pregnancy is associated with an increased risk of preeclampsia, making prophylactic aspirin therapy important for reducing maternal and fetal morbidity and mortality 1
- The American Diabetes Association specifically recommends a higher dose (100-150 mg/day) for pregnant women with diabetes, as standard lower doses have been shown to be ineffective 1, 2
- In the United States, low-dose aspirin is available in 81-mg tablets, so a dosage of 162 mg/day (two tablets) may be acceptable to achieve the recommended therapeutic range 1
- Meta-analyses have demonstrated that low-dose aspirin <100 mg is not effective in reducing preeclampsia, which is why doses >100 mg are required for pregnant women with diabetes 1
Timing of Initiation
- Aspirin prophylaxis should be initiated between 12 and 16 weeks of gestation (late first trimester) for optimal effect 1, 3
- Treatment should continue daily until delivery 4
- Starting earlier than 12 weeks has not been shown to provide additional benefits, while starting later may reduce effectiveness 3
Safety Profile
- Low-dose aspirin use in pregnancy is considered safe with a low likelihood of serious maternal or fetal complications 4, 5
- There is no evidence of increased risk for placental abruption, postpartum hemorrhage, or perinatal mortality with low-dose aspirin use 3
- A cost-benefit analysis has concluded that this prophylactic approach would reduce morbidity, save lives, and lower healthcare costs 1
Additional Benefits Beyond Preeclampsia Prevention
- Low-dose aspirin provides approximately 14% reduction in risk of preterm birth 3
- It also provides approximately 20% reduction in risk of intrauterine growth restriction (IUGR) 3
- Mean birthweight may increase by approximately 130g with aspirin prophylaxis 3
Potential Limitations and Considerations
- While the recommendation for aspirin prophylaxis in diabetic pregnancies is strong, some studies have questioned its effectiveness specifically in women with pregestational diabetes 6
- A retrospective observational study suggested a potential association between aspirin use and increased risk of large for gestational age (LGA) infants in women with type 1 diabetes of short duration, though this finding requires further investigation 6
- The evidence specifically regarding aspirin's effectiveness in pregnant women with preexisting diabetes is still being developed, though the overall recommendation remains strong based on high-risk status 1
Practical Implementation
- For women in the United States where 81 mg tablets are standard, two tablets daily (162 mg) is an acceptable dosage to achieve the recommended range 1
- Women with type 1 or 2 diabetes should be counseled about the importance of aspirin prophylaxis at their initial prenatal visit to ensure timely initiation 2
- Aspirin should be continued until delivery, as the risk of preeclampsia persists throughout pregnancy 4