Hypertensive (high blood pressure) disorders of pregnancy are a major cause of poor pregnancy outcomes in both Canada and internationally. These disorders encompass pre-existing hypertension, gestational hypertension (develops during pregnancy) and preeclampsia. Preeclampsia develops when an individual has high blood pressure and involvement of other organ systems, such as liver dysfunction. This is risky for both the health of the pregnant person and baby.
Low-Dose Aspirin Therapy
A substantial amount of research suggests that low dose Aspirin (162 mg) taken by an at-risk pregnant person daily until 36 weeks of pregnancy is effective in reducing the risk of developing preeclampsia. Based on available evidence, low-dose aspirin therapy is not associated with any short- or long-term adverse outcomes. It is not beneficial for low-risk individuals.
Read this handout by the Association of Ontario Midwives on low dose ASA therapy.
Am I at risk?
If you have one of the following risk factors ASA is recommended:
- Your pre-pregnancy BMI is greater than 30
- You used ART (artificial reproductive technology to get pregnant
- History of hypertensive disease in previous pregnancy
- Autoimmune disease (e.g., Systemic Lupus)
- Chronic hypertension
- Chronic kidney disease
If you have two or more of the following risk factors ASA is recommended:
- First pregnancy
- Age 40 or older
- Multiple pregnancy (i.e., twins)
- Your sister or mother had pre-eclampsia
- Have had a baby who was diagnosed small for gestational age (SGA) or stopped growing inside you (IUGR)
- Have had a placental abruption
- Have had a stillborn baby
Lastly, if you decide to have genetic screening in the form of eFTS, we will also look at two specific markers: PAPP-A and PIGF. If either of these marker are low, you are at higher risk for pre-eclampsia and ASA is recommended.
Your midwife will have you complete a self-screening tool prior to your first appointment. If low-dose aspirin therapy is indicated, she will discuss the appropriate plan of care for you based on your risk factors.