First-lineDisprin, generic

Aspirin (low-dose)

Antiplatelet (COX-1 inhibitor)

75–150 mg nocte from 12/40 — prevents pre-eclampsia in high-risk women.

Oral

First-line for

Pre-eclampsia prophylaxis (high/moderate risk)
Recurrent miscarriage with APS
Prior IUGR / placental insufficiency

Mechanism

Irreversibly acetylates COX-1 → ↓ thromboxane A₂ (platelet) > prostacyclin (endothelium), shifting balance to vasodilation & ↓ platelet aggregation in placental bed.

Who needs it — NICE high-risk

H — Hypertension prior pregnancy
E — Established CKD
L — Lupus / APS
P — Pre-existing HTN
D — Diabetes (T1/T2)

Dosing

Dose: 75–150 mg PO nocte
Start: 12/40 (ideally <16/40)
Stop: 36/40 or delivery

Contraindications

AbsoluteAspirin allergy / NSAID-induced asthma
CautionActive peptic ulcer, bleeding diathesis

Side effects

Dyspepsia
Minor bleeding
Rarely Reye’s in children (not relevant)

Fetal & maternal notes

• Not teratogenic at low dose.
• Safe in breastfeeding (low dose).

Key interactions

Warfarin
Avoid
↑ bleeding — usually avoided
LMWH
Caution
Often combined in APS — monitor

Clinical pearls

💡 NICE: 75–150 mg from 12/40 if ≥1 high-risk or ≥2 moderate-risk factors.
💡 Take at night — better BP & PE prevention (ASPRE trial).

Content last reviewed: REPLACE_ME (e.g. 2026-07)

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