Unexplained elevated maternal serum alpha-fetoprotein: what is the appropriate follow-up?

Unexplained elevations of maternal serum alpha-fetoprotein exist in approximately 1% of the obstetric population. A consensus has been reached that these women face an increased risk of adverse pregnancy outcome. Whether their overall risk can be altered by the currently available surveillance modalities, however, remains controversial. Current research has focused on identifying those pregnancies with the highest risks of either fetal growth restriction, pre-eclampsia, preterm delivery or intrauterine fetal demise. Markedly increased maternal serum alpha-fetoprotein (over 4.0 multiples of the median), elevations of other serum markers such as human chorionic gonadotropin and abnormal umbilical Doppler flow are associated with the greatest risk of poor pregnancy outcome. When initiating surveillance of the pregnancy with unexplained elevated maternal serum alpha-fetoprotein consideration of these factors is receiving increased attention.