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Antiplatelet — Pre-eclampsia Prophylaxis Pregnancy: Indicated in pregnancy for pre-eclampsia prevention; stop before delivery

Aspirin (Low-Dose — Pre-eclampsia Prevention)

Brand names: Aspirin 75 mg (generic)

Adult dose

Dose: 75-150 mg once daily
Route: Oral
Frequency: Once daily at night (better absorption and compliance)
Max: 150 mg/day
NICE NG133: Start from 12 weeks gestation; continue until birth. Offer to women with 1 high-risk or 2 moderate-risk factors for pre-eclampsia. High risk: prior pre-eclampsia, CKD, autoimmune disease, diabetes, chronic hypertension

Paediatric dose

Dose: Not applicable N/A/kg
Route: N/A
Frequency: N/A
Max: N/A
Maternal medication — not a paediatric indication

Dose adjustments

Renal

Use with caution in significant renal impairment

Hepatic

Avoid in severe hepatic impairment

Paediatric weight-based calculator

Maternal medication — not a paediatric indication

Clinical pearls

  • ASPRE trial: 150 mg aspirin at night from 11-14 weeks reduces preterm pre-eclampsia by 62% in high-risk women identified by first-trimester combined screening
  • NICE NG133 high-risk factors: pre-eclampsia in previous pregnancy, CKD, autoimmune disease (SLE, antiphospholipid syndrome), diabetes (type 1 or 2), chronic hypertension
  • Evening dosing: better anti-hypertensive effect during sleep-time peak BP; circadian variation in thromboxane production also supports night-time dosing
  • Stop at 36 weeks: reduces bleeding risk at delivery; some centres continue until 37 weeks — follow local protocol
  • Low-dose aspirin is safe throughout pregnancy at 75-150 mg — does not cause premature ductus closure (dose-dependent; only high doses above 300 mg carry this risk)

Contraindications

  • Active GI ulceration
  • Third trimester haemorrhagic risk (use with obstetric caution)
  • Aspirin hypersensitivity

Side effects

  • GI upset
  • Minor bleeding
  • Premature closure of ductus arteriosus (high-dose — not at 75-150 mg prophylactic doses)
  • Neonatal platelet effects (minimal at low dose)

Interactions

  • NSAIDs (additive bleeding)
  • Anticoagulants (increased bleeding risk)
  • Antihypertensives (weak interaction)

Monitoring

  • Blood pressure monitoring throughout pregnancy
  • Fetal growth scanning
  • Urine protein:creatinine ratio

Reference: BNFc; BNF 90; NICE NG133 (Hypertension in Pregnancy); ASPRE Trial (Rolnik et al. NEJM 2017); RCOG Pre-eclampsia Guideline. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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