From the Guidelines
Low-dose Acetylsalicylic acid (Aspirin) is recommended for pregnant women at high risk for preeclampsia.
Benefits of Low-Dose Aspirin
The benefits of low-dose aspirin in pregnancy include:
- Reduction in risk for preeclampsia by 24% 1
- Reduction in risk for preterm birth by 14% 1
- Reduction in risk for intrauterine growth restriction (IUGR) by 20% 1
Harms of Low-Dose Aspirin
The harms of low-dose aspirin in pregnancy are considered to be no greater than small 1.
Key Considerations
- Low-dose aspirin (range, 60 to 150 mg/d) is recommended for asymptomatic pregnant women at increased risk for preeclampsia and who have no prior adverse effects with or contraindications to low-dose aspirin 1
- There are no validated methods of identifying women at high risk for preeclampsia on the basis of biomarkers, clinical diagnostic tests, or medical history 1
- The anti-inflammatory, antiangiogenesis, and antiplatelet properties of low-dose aspirin are believed to account for its preventive effect on preeclampsia 1
From the FDA Drug Label
If pregnant or breast-feeding, ask a health professional before use. It is especially important not to use aspirin at 20 weeks or later in pregnancy unless definitely directed to do so by a doctor because it may cause problems in the unborn child or complications during delivery. The role of low-dose Acetylsalicylic acid (Aspirin) in pregnancy is not explicitly stated for doses below a certain threshold, but aspirin should not be used at 20 weeks or later in pregnancy unless directed by a doctor due to potential problems in the unborn child or complications during delivery 2.
- Pregnant women should consult a health professional before using aspirin.
- Low-dose aspirin use in pregnancy is not directly addressed in the provided label, and therefore, no conclusion can be drawn about its specific role.
From the Research
Role of Low-Dose Acetylsalicylic Acid (Aspirin) in Pregnancy
- The use of low-dose aspirin (LDA) in pregnancy has become routine for women with a history of preeclampsia and associated poor pregnancy outcomes 3.
- LDA is indicated in patients considered to be at risk for development of preeclampsia, with optimal dosing and timing of treatment initiation under investigation 3, 4.
- Studies suggest that early initiation of LDA, at a dose of >100mg, decreases the development of preeclampsia in patients considered at increased risk 3, 5, 6.
- The American College of Obstetricians and Gynecologists recommends daily low-dose aspirin beginning in the late first trimester for women with a history of early-onset preeclampsia and preterm delivery at less than 34 0/7 weeks of gestation, or for women with more than one prior pregnancy complicated by preeclampsia 4.
- Aspirin prophylaxis is also recommended for women at high risk of preeclampsia and should be initiated between 12 weeks and 28 weeks of gestation (optimally before 16 weeks) and continued daily until delivery 4, 6.
Maternal and Fetal Outcomes
- Aspirin prophylaxis substantially lowers the risk of pre-eclampsia, preterm birth, perinatal mortality, and intrauterine growth retardation without elevated bleeding risks 5.
- Low-dose aspirin considerably enhances neonatal birth weight but does not decrease the risk of gestational hypertension 5.
- The subgroup analysis revealed substantially reduced pre-eclampsia risk and enhanced birth weight and gestational age at delivery in women who initiated aspirin before 20 weeks of gestation 5.
Safety and Risks
- Aspirin has potential risks, including inhibition of platelet function and contribution to maternal and fetal bleeding 7.
- Aspirin crosses the placenta and has been associated with an increased risk of vascular disruptions, particularly gastroschisis and possibly premature closure of the ductus arteriosus 7.
- However, large trials demonstrate low-dose aspirin's relative safety and generally positive effects on reproductive outcomes 7.