Maternal serum alpha-fetoprotein and human chorionic gonadotrophin in pregnancies conceived after intracytoplasmic sperm injection and conventional in-vitro fertilization

Data in the Caucasian population suggest that maternal serum alpha-fetoprotein (AFP) and unconjugated oestriol concentrations are reduced and human chorionic gonadotrophin (HCG) concentrations are elevated in pregnancies conceived after in-vitro fertilization (IVF), leading to a higher than expected Down's syndrome screen-positive rate. There are no previous reports on the serum marker values in pregnancies conceived after intracytoplasmic injection (ICSI). Between 1996 and 1998, we measured maternal serum total HCG and AFP concentrations between 15 and 20 weeks gestation in 42 in-vitro fertilization (IVF) pregnancies and 23 ICSI pregnancies with known normal outcome. The results were compared with that of 2799 naturally occurring singleton pregnancies who were known to have a normal outcome. Median AFP multiple of the median (MOM) in ICSI pregnancies was significantly reduced to 0.76 compared with both that of the controls and that of the IVF pregnancies. For the IVF pregnancies, median HCG MOM was elevated to 1.15, and median AFP MOM was reduced to 0.88 compared with the controls, but these differences were not statistically significant. In both the IVF and ICSI pregnancies the changes might result in a falsely high Down's syndrome risk. In particular, the reduced AFP concentration in ICSI pregnancies was substantial. If this preliminary finding is substantiated by other series, the appropriate adjustment needs to be made to allow for valid interpretation of the screen result and to avoid an unnecessarily high false positive rate.