Home
Disease Knowledge Center Drug Hub Monographs Drug Interactions Pregnancy Drug Safety Drug Recalls & Alerts OTC Navigator
Virtual Simulators Hub Clinical Cases Simulator Nutrition & Macro Calculator
Questo Insights Global Opportunities Hub AI Research Assistant Citation & Reference Generator Scholarships & Essay Planner Visa & Mobility Navigator English Assessment Test
Verified Jobs Board Pharmacy Clearance Pharmacies Directory
Practice Quizzes STEM Academy Toolkits
Medical Case Donations Opportunity Crowdfunding Community Forums Courses Academy
Back to Safety Checker

Aspirin

Salicylate / Antiplatelet & NSAID

Alias: Aspirin FDA Category B/C (Low-Dose 81mg) / FDA Category D (High-Dose 3rd Tri) FDA PLLR & ACOG / USPSTF Consensus
Low-Dose Recommended for Pre-eclampsia Prophylaxis

Low-dose aspirin (81–162 mg/day) is strongly recommended by ACOG, USPSTF, and FDA starting at 12 weeks for women at high risk of pre-eclampsia. Full analgesic doses (>325 mg/day) in 3rd trimester are FDA Category D and contraindicated.

Medical Disclaimer: This report is for educational and informational purposes only. It does not replace professional medical advice. Always consult your healthcare provider before making any medication decisions during pregnancy.
Pregnancy Summary
Clinical overview for pregnancy

FDA & ACOG guidelines: low-dose (81 mg) prevents pre-eclampsia and fetal growth restriction. Full doses in late pregnancy risk premature closure of the ductus arteriosus and peripartum hemorrhage.

Trimester Safety Timeline
Safety profile across all three trimesters
1st Trimester
Weeks 1 – 12
Low-Dose Preferred (Wk 12+)

ACOG guidelines recommend initiating low-dose (81 mg/day) between weeks 12 and 28 for pre-eclampsia prevention.

2nd Trimester
Weeks 13 – 27
Low-Dose Safe & Indicated

Low-dose aspirin is safe and effective for high-risk pre-eclampsia prophylaxis.

3rd Trimester
Weeks 28 – Birth
Low-Dose Safe / Full-Dose Avoid

Low-dose (81 mg) is continued up to 36-37 weeks. High analgesic doses are contraindicated.

Placental Transfer
Does this medication cross the placenta?
Crosses Placenta
Yes
Transfer Extent
High (Crosses placenta rapidly)

Low dose selectively inhibits platelet thromboxane A2 in maternal circulation to improve placental blood flow.

Fetal Risk Assessment
Potential effects on the developing fetus
Low-Dose (81 mg) Safety Verified

USPSTF meta-analyses of >30,000 pregnant women show no increase in congenital defects at 81 mg daily.

Maternal Risk Assessment
Potential maternal side effects during pregnancy
Bleeding & Gastric Irritation

Discontinue low-dose aspirin at 36-37 weeks prior to labor to prevent maternal peripartum bleeding.

Clinical Recommendation
Professional prescribing guidance
Indicated for Pre-eclampsia Prophylaxis

Prescribe low-dose aspirin 81 mg daily from 12-28 weeks through 36 weeks for mothers with pre-eclampsia risk factors.

If Already Taken
"I took this before knowing I was pregnant"
1
Verify Dose

If taking 81 mg low-dose for pre-eclampsia, continue as instructed by your OB. Avoid full-strength (325 mg) pain doses.

Pregnancy Monitoring Protocol
Recommended follow-up and surveillance
Obstetric Surveillance
  • Blood pressure and urine protein monitoring for pre-eclampsia
  • Stop at 36 weeks prior to delivery
Safer Alternatives
Active ingredients with better pregnancy safety profiles
acetaminophen
First-line choice if aspirin was taken purely for pain/fever relief.
Safe
Professional Clinical Notes
Key prescribing considerations and clinical pearls
  • USPSTF & ACOG Recommendation: Low-dose aspirin (81 mg/day) reduces pre-eclampsia risk by 24%.
Patient-Friendly Explanation
In simple, easy-to-understand language
Easy to Understand

Low-dose aspirin (81 mg) is prescribed by doctors to prevent high blood pressure (pre-eclampsia) in pregnancy. High doses for headache should be avoided.

Frequently Asked Questions
Common questions about Aspirin in pregnancy

Yes, 81 mg low-dose aspirin is recommended by ACOG starting at 12 weeks for women at risk of pre-eclampsia.

Evidence Level
Quality of available safety data
FDA PLLR & ACOG / USPSTF Consensus

Supported by major clinical trials, FDA PLLR standards, and national consensus guidelines.

References & Primary Sources
Official U.S. Food & Drug Administration (FDA) PLLR & ACOG Clinical Database
All pregnancy safety evaluations, risk categories, and drug monographs are compiled directly from U.S. FDA Pregnancy and Lactation Labeling Rule (PLLR) standards and approved FDA prescribing labels.
  1. 1
    U.S. Food and Drug Administration (FDA) PLLR — FDA Pregnancy and Lactation Labeling Rule & Approved Prescribing Information Database Last updated: Official FDA Standard
  2. 2
    FDA Center for Drug Evaluation and Research (CDER) — FDA MedWatch & Black Box Warning Database Last updated: Official FDA Standard
  3. 3
    ACOG Practice Bulletins & Guidelines — American College of Obstetricians and Gynecologists Clinical Recommendations Last updated: 2025 Clinical Edition
  4. 4
    Briggs Drugs in Pregnancy and Lactation — Reference Guide to Fetal and Neonatal Risk (12th Edition) Last updated: 2025 Clinical Edition
Search Another Medication

System Notice

Confirm Action