title: Fetal serum alpha-fetoprotein in alloimmunised pregnancies.
abstract: OBJECTIVE
  Maternal serum alpha-fetoprotein (AFP) levels have been known to be increased in red blood cell alloimmunisation. Since AFP is now thought be a pro-erythropoietic factor, we wished to evaluate fetal serum levels of AFP in cases of alloimmunised pregnancies.
  
  
  METHODS
  We studied AFP levels in 32 fetal serum samples from women with red blood cell alloimmunisation at the time of the first fetal blood sampling. We expressed the levels of AFP and haemoglobin as absolute numbers and as delta values (number of SDs by which the observed value differed from the normal mean for the same gestation). Main outcome measures were fetal serum AFP levels and fetal haemoglobin concentration.
  
  
  RESULTS
  Overall, fetal AFP level was higher than normal in the cases (delta values 2.4 +/- 5.5 SD). However, mildly affected non-hydropic cases had higher levels than severely affected fetuses with hydrops.
  
  
  CONCLUSIONS
  Fetuses affected by red blood cell alloimmunisation have increased levels of serum AFP but these levels fall back to low levels in severe anaemia especially with hydrops, which could represent the failing of a compensatory erythropoietic mechanism. Our results suggest that fetal haematopoiesis is activated early in red blood cell alloimmunisation but was subsequently impaired.
authors.affiliation: Fetal Medicine Research Unit, Department of Obstetrics and Gynaecology, St Michael's Hospital, University of Bristol, Bristol, UK. J.Bartha@bristol.ac.uk
authors.forename: Jose L
authors.initials: JL
authors.lastname: Bartha
authors.forename: Gayle
authors.initials: G
authors.lastname: Harrison
authors.forename: Phillipa M
authors.initials: PM
authors.lastname: Kyle
authors.forename: Peter W
authors.initials: PW
authors.lastname: Soothill
mesh_terms: D000328:Adult; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011296:Prenatal Diagnosis; D012016:Reference Values; D012203:Rh Isoimmunization / Q000097:blood*; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D006454:Hemoglobins; D000509:alpha-Fetoproteins