Does amniotic fluid alpha-fetoprotein have diagnostic or prognostic value at the time of second midtrimester genetic amniocentesis?

In order to assess the usefulness of amniotic fluid alpha-fetoprotein (AFP) levels at the time of midtrimester genetic amniocentesis, 4,430 cases were retrospectively studied to compare the high, normal or low AFP values with the karyotype characteristics and fetal anatomy using ultrasound (US) scanning and confirmed by postnatal evaluation or necroscopy in the case of termination of pregnancy. All the cases presenting malformations were correctly diagnosed by US examinations. AFP levels over the 2nd standard deviation (SD) were found in 112 cases (2.52%) and below the 2nd SD in 11 cases (0.24%). The characteristics of these cases are presented and discussed. According to our results, it is concluded that routine assessment of AFP at the time of midtrimester genetic amniocentesis, if coupled with optimal US scanning, is no longer justified.