An Rh-alloimmunized gravida at 28 weeks has serial middle cerebral artery peak systolic velocity measurements. The value crosses 1.5 multiples of the median for gestation. The most appropriate next step is:
- A Fetal blood sampling with intrauterine transfusion ✓
- B Immediate caesarean delivery
- C Repeat measurement after 2 weeks
- D Intravenous immunoglobulin to the mother
Correct answer: A. Fetal blood sampling with intrauterine transfusion
Explanation
An MCA-PSV above 1.5 MoM detects moderate to severe fetal anaemia from haemolysis with high sensitivity and has replaced serial amniocentesis as the trigger for invasive testing. Cordocentesis confirms the haematocrit and allows transfusion in the same procedure. Delivery at 28 weeks would expose a preterm anaemic fetus, and IVIG is reserved for salvage situations such as recurrent early severe hydrops.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.