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| low dose aspirin |
The current
ACOG recommendation for supplementing low dose aspirin for reducing the risk of
developing preeclampsia is based on report by Task Force on Hypertension in
Pregnancy in 2013.
The task
force recommended 60-80 mg of aspirin started late first trimester for all
women who are at risk by their obstetric history:
- history of preeclampsia in more than one prior pregnancy.
- history of early onset preeclampsia with preterm delivery at <34 weeks' gestation.
The U.S.Preventive Services Task Force (USPSTF) conducted a systematic review and
meta-analysis of several good quality RCTs and published the results as
clinical guidelines. It expanded its list of high risk pregnancies at risk for
developing preeclampsia in 2014.[1] The list was divided into 3 categories: high,
medium and low risk for developing preeclampsia.
1) Women are considered
at high risk if one or more of the following factors are present:
- History of preeclampsia, especially when accompanied by an adverse outcome
- Multifetal gestation
- Chronic hypertension
- Type 1 or 2 diabetes
- Renal disease
- Autoimmune disease such as systemic lupus erythematous, antiphospholipid syndrome.
2) Women are
considered at moderate risk if they have several of these moderate-risk factors:
- Nulliparity
- Obesity (body mass index >30 kg/m2)
- Family history of preeclampsia (mother or sister)
- Sociodemographic characteristics (African American race, low socioeconomic status)
- Age ≥35 years
- Personal history factors (e.g., low birthweight or small for gestational age, previous adverse pregnancy outcome, >10-year pregnancy interval)
3) Women are
considered at low risk if they have:
- A history of uneventful term delivery.
ACOG issued
a practice advisory in July 2016[2]
supporting the recommendation by USPSTF to
consider the use of low-dose aspirin (81 mg/day), initiated between 12 and 28
weeks of gestation, for the prevention of preeclampsia, and recommends using
the high-risk factors as recommended by the USPSTF and listed above.
Supplementing
the low dose aspirin reduced the reduced the risk for preeclampsia by 24% in
clinical trials and reduced the risk for preterm birth by 14% and IUGR by 20%.
In a meta-analysis
of RCTs and observational studies, USPSTF did found any evidence of increased
risk of placental abruption, postpartum hemorrhage, or fetal intracranial
bleeding even in moderate to low risk patients.
It is estimated that ten million women develop preeclampsia each
year around the world, with 76,000 deaths due preeclampsia and related
hypertensive disorders. It is also responsible for 50,000 stillbirths and
early neonatal deaths in developing nations.
A woman in developing country is seven times more likely to
develop preeclampsia than a woman in a developed country, contributing to
10-25% of all Maternal mortality.
In the United States, it affects 5-8% of all pregnancies.
Establishing casualty, early detection and prevention of
preeclampsia along with identifying the women at risk has been the mainstay of
preeclampsia research in the last decade.
Link to USPSTF complete final recommendation can be found here.
Link to ACOG practice advisory can be found here.
[1] https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/low-dose-aspirin-use-for-the-prevention-of-morbidity-and-mortality-from-preeclampsia-preventive-medication
[2] http://www.acog.org/About-ACOG/News-Room/Practice-Advisories/Practice-Advisory-Low-Dose-Aspirin-and-Prevention-of-Preeclampsia-Updated-Recommendations
