What advice should be given to a pregnant Rh-negative woman with a history of abortion and previous anti-D immunoglobulin administration at 8 weeks of gestation?

Management of Rh-Negative Woman at 8 Weeks Gestation with Prior Abortion

The correct answer is A: She needs an indirect Coombs test at this stage to determine if she has already developed anti-D antibodies from a potential sensitization event.

Rationale for Antibody Screening

At the first prenatal visit (booking), the priority is to determine whether this Rh-negative patient has already been sensitized despite receiving anti-D immunoglobulin after her previous abortion 1. An indirect Coombs test (antibody screen) will identify if anti-D antibodies are present in her circulation, which would fundamentally change her pregnancy management 1.

• If the antibody screen is negative, she remains unsensitized and will follow standard Rh prophylaxis protocols 1
• If the antibody screen is positive, she is already sensitized and additional RhIg would be futile, requiring instead intensive fetal monitoring for hemolytic disease 1

Why the Other Options Are Incorrect

Option B: Risk Assessment is Inaccurate

The statement that feto-maternal hemorrhage risk is low at 8 weeks is misleading. While the volume of potential hemorrhage is small, fetal RBCs display RhD antigens from as early as 6 weeks gestation, making maternal sensitization possible even in early pregnancy 1. The risk of sensitization exists at any gestational age with bleeding or trauma 1.

Option C: Timing is Premature

She does not need anti-D immunoglobulin at 8 weeks gestation during routine booking 1. Standard prophylaxis timing includes:

• 28 weeks gestation for routine antenatal prophylaxis 1
• Within 72 hours of any sensitizing event (bleeding, trauma, invasive procedures) 1
• Within 72 hours postpartum if the infant is Rh-positive 1

The only indication for RhIg at 8 weeks would be a new sensitizing event such as vaginal bleeding, abdominal trauma, or threatened abortion 1.

Option D: Antepartum Hemorrhage Risk is Unrelated

Being Rh-negative does not inherently increase the risk of antepartum hemorrhage. This is a distractor with no pathophysiologic basis.

Clinical Algorithm for This Patient

1. Perform indirect Coombs test (antibody screen) at booking 1
2. If negative: Counsel on standard RhIg prophylaxis schedule (28 weeks, postpartum, and for any bleeding/trauma events) 1
3. If positive: Refer to maternal-fetal medicine for serial fetal monitoring and management of potential hemolytic disease 1

Critical Pitfall to Avoid

Do not assume prior RhIg administration guarantees protection. Sensitization can occur if:

• RhIg was given outside the 72-hour window 1
• The dose was inadequate for the volume of feto-maternal hemorrhage 1
• There was a subsequent unrecognized sensitizing event 1

The antibody screen at booking is the only way to confirm her current sensitization status and guide appropriate management for this pregnancy 1.