A 23-year-old primigravida at 16 weeks has haemoglobin 9.6 g/dL, MCV 62 fL, RDW 13 percent, and serum ferritin 40 ng/mL. Haemoglobin electrophoresis shows HbA2 of 5.8 percent. Her husband has not been tested. What is the MOST appropriate next step?

• A Start oral iron and repeat electrophoresis after 8 weeks
• B Reassure, as isolated raised HbA2 is a normal variant in pregnancy
• C Refer for chorionic villus sampling now
• D Test the husband for thalassaemia carrier status and offer genetic counselling ✓

Explanation

Microcytosis with normal or high ferritin, low RDW and HbA2 above 3.5 percent establishes beta thalassaemia minor. The critical antenatal action is paternal testing, because if the father is also a carrier there is a 25 percent risk of beta thalassaemia major, warranting prenatal diagnosis. Iron will not help since stores are adequate. Chorionic villus sampling is offered only after both parents are confirmed carriers. Raised HbA2 is never a normal variant of pregnancy.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.