From the Guidelines
Aspirin should be prescribed to pregnant women at high risk for preeclampsia, as it has been shown to reduce the risk of preeclampsia, preterm birth, and intrauterine growth restriction (IUGR) by 24%, 14%, and 20%, respectively, with no significant increase in adverse events 1.
Benefits of Aspirin in Pregnancy
The use of low-dose aspirin in pregnancy has been found to have substantial benefits, including:
- Reduction in risk for preeclampsia by 24% 1
- Reduction in risk for preterm birth by 14% 1
- Reduction in risk for IUGR by 20% 1
Harms of Aspirin in Pregnancy
The harms of low-dose aspirin in pregnancy have been found to be no greater than small, with no significant increase in:
Clinical Considerations
Aspirin should only be prescribed to asymptomatic pregnant women who are at increased risk for preeclampsia and have no prior adverse effects with or contraindications to low-dose aspirin 1. The American College of Obstetricians and Gynecologists (ACOG) guidelines recommend initiating low-dose aspirin between 12-16 weeks of gestation and continuing until 36 weeks 1. However, a more recent study found that the implementation of these guidelines did not significantly decrease the incidence of superimposed preeclampsia, small for gestational age, and preterm birth 1.
Recommendation
Low-dose aspirin (60-150 mg daily) should be prescribed to pregnant women at high risk for preeclampsia, as the benefits of reducing the risk of preeclampsia, preterm birth, and IUGR outweigh the potential harms 1.
From the FDA Drug Label
If pregnant or breast-feeding ask a health professional before use. it is especially important to use aspirin during the last 3 months of pregnancy unless definitely directed to do so by a doctor because it my cause problems in the unborn child or complications during delivery. Aspirin use in pregnancy should be done with caution, especially in the last 3 months. It is recommended to consult a doctor before using aspirin during pregnancy, as it may cause problems in the unborn child or complications during delivery 2.
From the Research
Aspirin Use in Pregnancy
- Aspirin has been used during pregnancy to prevent or delay the onset of preeclampsia, with low-dose aspirin considered safe and associated with a low likelihood of serious maternal or fetal complications 3.
- The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine support the U.S. Preventive Services Task Force guideline criteria for prevention of preeclampsia, recommending low-dose aspirin (81 mg/day) prophylaxis in women at high risk of preeclampsia 3.
- Aspirin has been proven efficient to prevent pre-eclampsia and fetal growth restriction in high-risk patients, but its benefits have not been demonstrated for vascular placental disease prevention in low-risk patients or in cases of unexplained recurrent miscarriages 4.
Indications for Aspirin Use
- Women at risk of preeclampsia are defined based on the presence of one or more high-risk factors, including history of preeclampsia, multifetal gestation, renal disease, autoimmune disease, type 1 or type 2 diabetes, and chronic hypertension 3.
- Aspirin is recommended for women with more than one of several moderate-risk factors for preeclampsia, including first pregnancy, maternal age of 35 years or older, a body mass index greater than 30, family history of preeclampsia, sociodemographic characteristics, and personal history factors 3.
- Prior preeclampsia, chronic hypertension, autoimmune disease, and diabetes mellitus type 1 or 2 are recognized as solitary major risk factors for aspirin administration in 93.7% of clinical practice guidelines 5.
Dosage and Timing
- Low-dose aspirin prophylaxis should be initiated between 12 weeks and 28 weeks of gestation, optimally before 16 weeks, and continued daily until delivery 3.
- The recommended dose of aspirin varies among clinical practice guidelines, with some recommending 81 mg/day and others recommending 100 mg/day or more 6, 5.
- The gestational age at which aspirin should be commenced also varies among clinical practice guidelines, with some recommending initiation before 16 weeks of pregnancy 6, 5.