Post-abortion care after uterine evacuation for missed abortion at 10 weeks is being discussed. The patient is Rh D negative with blood group O-negative. The father's blood group is not known. What is the correct Rh immunoglobulin (RhIg) dose and timing?
- A 50 mcg anti-D RhIg within 72 hours as the feto-placental volume is small at 10 weeks ✓
- B 300 mcg anti-D RhIg within 72 hours of the procedure
- C RhIg is not required as miscarriage is a spontaneous event and sensitization risk is negligible
- D Kleihauer-Betke test should be done first to determine if RhIg is needed at this gestational age
Explanation
For pregnancy loss or invasive procedures before 12 weeks gestation, the recommended anti-D dose is 50 mcg (250 IU) RhIg, sufficient to cover the smaller feto-placental blood volume at this gestational age. The full 300 mcg dose is recommended from 12 weeks onwards. ACOG recommends anti-D prophylaxis for all Rh-negative women after spontaneous or induced abortion, ectopic pregnancy, or invasive procedures, regardless of trimester. Kleihauer-Betke test is not required before 12 weeks as a standard dose covers the feto-placental volume. The 72-hour window applies (though benefit exists up to 28 days in some guidelines).
Reference: Williams Obstetrics, 26th ed.
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Written and medically reviewed by the StethoPrep medical team.