Synopsis
Apply the June 2026 NICE anti-D thresholds accurately, explain sensitisation and consent simply, and prevent both unnecessary treatment before 12 weeks and missed prophylaxis at 12 weeks.
- Anti-D immunoglobulin prevents an RhD-negative, non-sensitised pregnant person forming immune anti-D after exposure to RhD-positive fetal red cells.
- Do not offer anti-D for ectopic pregnancy, miscarriage or threatened miscarriage up to and including 11+6 weeks, even after surgical management.
- Use ultrasound gestation rather than the last menstrual period when the two estimates disagree.
Key red flags
Syncope, shoulder-tip pain, severe unilateral pelvic pain or peritonism suggesting a ruptured ectopic pregnancy.
Investigation priorities
Establish the best gestational estimate and pregnancy location or viability where clinically required.
Management branches
Ultrasound gestation is no more than 11+6 weeks and the event is ectopic pregnancy, miscarriage or threatened miscarriage.
- Manage pain, bleeding, pregnancy location and viability through the appropriate urgent or early-pregnancy pathway.
- Do not prescribe anti-D, including after manual vacuum aspiration, laparoscopy or other surgical management below 12+0 weeks.
Key medicines
Anti-D immunoglobulinAt 12+0 to 12+6 weeks give at least 250 IU (50 micrograms), using the authorised intramuscular or intravenous route for the selected product; a larger stocked dose may be used when the minimum-size vial is unavailable.