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Low-Dose Aspirin for Prevention of Preeclampsia

Low Dose Aspirin for Prevention of Preeclampsia

Last Updated August 8, 2022

 

Background

In December 2021 the American College of Obstetricians and Gynecologists (ACOG) and the Society of Maternal Fetal Medicine (SMFM) issued a Practice Advisory on Low-Dose Aspirin Use for the Prevention of Preeclampsia and Related Morbidity and Mortality[i] based on new guidance and supporting evidence from the United States Preventive Service Task Force (USPSTF).  In that new guidance, the USPSTF “concludes with moderate certainty that there is a substantial net benefit of daily low-dose aspirin use to reduce the risk for preeclampsia, preterm birth, small for gestational age/intrauterine growth restriction, and perinatal mortality in pregnant persons at high risk for preeclampsia.” (September 2021, JAMA).[ii] 

Appropriate Candidates for Therapy (condensed)

** Please note that with these new guidelines, most pregnant patients in South Carolina will be candidates for low dose aspirin therapy.  Consider asking yourself for each new Ob visit, “why would this patient not be a candidate for aspirin?”

Low dose aspirin should be recommended to pregnant people with ONE or more of these risk factors – each of which is associated with a presumed preeclampsia risk of at least 8%.

 

Low dose aspirin should be recommended to pregnant people with TWO or more of these risk factors and can be considered for pregnant people with ONE or more of these risk factors.

Personal history of preeclampsia

Nulliparity

Multifetal gestation

BMI > 30

Chronic hypertension

In vitro fertilization

Type 1 Diabetes

Black race, a proxy for exposure to racism

Type 2 Diabetes (pregestational)

Lower income+

Kidney Disease

Age 35 or older

Autoimmune disease (ie, SLE or APLAS)

Personal history factors (low birthweight or SGA, previous adverse pregnancy outcome,

> 10 year pregnancy interval)

 

Family history of preeclampsia (mother or sister)

+ not defined in original document

Dosing Considerations

Recent studies suggest that timing of aspirin administration and dose also play an important role in preeclampsia prevention.[iii][iv]

In the December 2021 guidance, the USPSTF notes this about dosing:

“Effective dosages of low-dose aspirin range from 60 to 150mg/d. Although studies did not evaluate a dosage of 81 mg/d, low-dose aspirin is available in the US as 81-mg tablets, which is a reasonable dose for prophylaxis in pregnant persons at high risk for preeclampsia. Low-dose aspirin use should be initiated after 12 weeks of gestation (studies most often initiated before 20 weeks of gestation).”i

In an expert commentary from the February 2017 issue of the American Journal of Obstetrics and Gynecology, Drs. Tong, Moi and Walker suggest the following:

“The dose-response data in the report of Roberge et al for the outcome of severe preeclampsia looked pretty convincing and suggests that the aspirin dose to prevent preeclampsia should not be less than 100 mg. Until this is assessed in IPD or head-to-head comparative studies, clinicians should prescribe aspirin at a dose of at least 100 mg.”[v]

Finally, a 2017 multicenter RCT of aspirin versus placebo for the prevention of preterm preeclampsia in more than 1,700 high risk pregnancies demonstrated a 62% risk reduction in pregnancies exposed to 150 mg of aspirin daily versus placebo.iv

Given the structural limitations in aspirin dosing in the United States (offered in 81 mg and 325 mg tablets), and until such time as head-to-head dosing studies are conducted, we recommend prophylactic aspirin therapy for eligible women at a dose of no less than 81 mg daily with consideration of dosing up to 162 mg (two 81 mg tablets) daily at bedtime.

 

[ii] Henderson JT, Vesco KK, Senger CA, Thomas RG, Redmond N. Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2021 Sep 28;326(12):1192-1206.

[iii] Roberge S, Nicolaides K, Demers S, Hyett J, Chaillet N, Bujold E. The role of aspirin dose on the prevention of preeclampsia and fetal growth restriction: systematic review and meta-analysis. Am J Obstet Gynecol. 2017 Feb;216(2):110-120.e6

[iv] Rolnik DL,Wright D, Poon LC, et al. Aspirin versus placebo in pregnancies at high risk for preterm preeclampsia. N Engl J Med. 2017;377(70):613-622.

[v] Tong S, Mol BW, Walker SP. Preventing preeclampsia with aspirin: does dose or timing matter? Am J Obstet Gynecol. 2017 Feb;216(2):95-97. doi: 10.1016/j.ajog.2016.12.003.

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