A Rh-negative woman who had an anti-D injection at 28 weeks presents for delivery at 40 weeks. What is the indication for anti-D after delivery?
- A Anti-D is not required postpartum if given antenatally at 28 weeks
- B Anti-D 300 mcg is given if the neonate's cord blood is Rh-positive ✓
- C Anti-D is only required if cord blood Coombs' test is positive
- D Anti-D is required regardless of neonatal Rh status
Correct answer: B. Anti-D 300 mcg is given if the neonate's cord blood is Rh-positive
Explanation
Antenatal anti-D at 28 weeks does not preclude the need for postpartum anti-D; the antenatal dose provides prophylaxis during pregnancy but a postnatal dose (300 mcg within 72 hours) is given specifically to prevent sensitisation from delivery-related FMH if the neonate is Rh-positive. If the neonate is Rh-negative, postnatal anti-D is unnecessary. Cord blood Rh typing is therefore mandatory before deciding on postnatal anti-D.
Reference: Williams Obstetrics, 26th ed.
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