For clinicians
Low-dose aspirin
ASA, baby aspirin, acetylsalicylic acid 81mg
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Bottom lineBottom line: low-dose aspirin (commonly 81-162 mg) is recommended for pre-eclampsia prophylaxis in higher-risk pregnancies (SLE, antiphospholipid antibodies, prior pre-eclampsia), ideally started by 12-16 weeks. Distinct from anti-inflammatory-dose NSAIDs; compatible across pregnancy and lactation.
By reproductive phase
| Phase | Position | Detail | Evidence |
|---|---|---|---|
| Pre-conception | Use if needed | May begin peri-conception in high-risk patients; otherwise start early second trimester.[1] | ●●○○low evidenceconditional |
| 1st trimester | Continue | ACR 2020 conditionally recommends low-dose aspirin (81 or 100 mg daily) beginning in the first trimester in SLE, and in aPL-positive pregnancies as pre-eclampsia prophylaxis.[1, 4] | ●●●○moderate evidenceconditional |
| 2nd/3rd trimester | Continue | Continue per obstetric plan.[1] | ●●○○low evidenceconditional |
| Breastfeeding | Continue | Low-dose aspirin compatible with lactation.[3] | ●●●○moderate evidenceconditional |
| Paternal | Continue | No paternal concern.[3] | ●●○○low evidenceconditional |
Guideline comparison
| Guideline | Position | Strength |
|---|---|---|
| ACR 2020 | Conditionally recommends low-dose aspirin 81 or 100 mg daily beginning in the first trimester in SLE; conditionally recommends prophylactic aspirin in aPL-positive pregnancy.[4] | Conditional |
| EULAR 2024 | Low-dose aspirin for pre-eclampsia prophylaxis is not listed as an antirheumatic drug in the EULAR 2024 Table 1; this indication is an ACR 2020 recommendation.[2] | Not addressed in EULAR drug table |
| BSR 2022/23 | Low-dose aspirin (<=150 mg/day) is recommended in all patients at high risk of pre-eclampsia (GRADE 1A) and may be continued throughout pregnancy until delivery (GRADE 1B); compatible with breastfeeding (GRADE 2C) and paternal exposure.[5] | Verified against BSR part 2 (Schreiber 2023) |
=Guideline divergence. VERIFIED (direction agrees, dose ceiling differs). ACR 2020: conditionally recommends low-dose aspirin 81 or 100 mg daily from the first trimester in SLE and aPL-positive pregnancy. BSR 2023: <=150 mg/day for all at high pre-eclampsia risk, continued to delivery. EULAR 2024 does not list aspirin in its antirheumatic drug table. Both stated ceilings sit within the low-dose range.
Key points
| Point | Evidence |
|---|---|
| ACR 2020 conditionally recommends low-dose aspirin for pre-eclampsia prophylaxis in SLE and aPL-positive pregnancy, beginning in the first trimester.[1, 4] | ●●●○moderate evidenceconditional |
Monitoring
- Confirm indication and start aspirin in the first trimester per ACR 2020.
References
- Sammaritano LR, et al. 2020 ACR Guideline for the Management of Reproductive Health in RMD. Arthritis Rheumatol. 2020;72(3):529-556. https://acrjournals.onlinelibrary.wiley.com/doi/10.1002/art.41191
- Ruegg L, et al. EULAR recommendations for antirheumatic drugs in reproduction, pregnancy, and lactation: 2024 update. Ann Rheum Dis. 2025;84(6):910-926. https://ard.eular.org/article/S0003-4967(25)00818-0/fulltext
- Russell MD, et al. BSR guideline on prescribing drugs in pregnancy and breastfeeding: comorbidity medications used in rheumatology practice. Rheumatology (Oxford). 2023;62(4):1388-1397. https://academic.oup.com/rheumatology/article/62/4/1388/6783016
- Guideline Central summary of the 2020 ACR Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases. https://www.guidelinecentral.com/guideline/7066/
- Schreiber K, Frishman M, Russell MD, et al. British Society for Rheumatology guideline on prescribing drugs in pregnancy and breastfeeding: comorbidity medications used in rheumatology practice. Rheumatology (Oxford). 2023;62(4):e89-e104. https://doi.org/10.1093/rheumatology/keac552