BOF: Transfusion (Obstetrics)

Under which of the following circumstances is estimation of feto-maternal haemorrhage volume NOT necessary? In all cases the women are known to be RhD negative. a) Following a fall in a woman in her 24th week of pregnancy whose partner has blood group A RhD negative. b) 38 year old woman has a diagnostic amniocentesis at 21 weeks due to high risk serology for fetal neural tube defect c) 24 year old primigravida having a small vaginal bleed in her 32nd week of pregnancy, 4 weeks after receiving routine antenatal anti-D prophylaxis (RAADP). d) 36 year old primagravida having a surgical termination of pregnancy at 16 weeks gestation. e) 28 year old woman undergoes uncomplicated external cephalic version in the 37th week of pregnancy.

Answer:

36 year old primagravida having a surgical termination of pregnancy at 16 weeks gestation.

Explanation:

Feto-maternal haemorrhage volume should be estimated following any potentially sensitising event occurring AFTER 20 weeks (miscarriage or antepartum haemorrhage, therapeutic termination, external cephalic version, instrumentation including cordocentesis or amniocentesis, maternal fall or abdominal trauma, intrauterine death and stillbirth). This includes a bleed following standard RAADP. Prior to this, fetal blood volume is unlikely to exceed the capacity of a standard dose of anti-D immunoglobulin. It would not be necessary in RhD positive women, with a known RhD negative baby, or when the mother has known immune anti-D.

Reference:

Austin E, Bates S, de Siilva M. Guidelines for the Estimation of Fetomaternal Haemorrhage (2009). British Committee for Standards in Haematology approved document.