AFP and Down syndrome: A number of studies published in the 1980s showed that first trimester AFP levels are reduced in cases of Down syndrome.9–12 A meta-analysis was performed in 1999 encompassing 26 studies and 542 cases showing a geometric mean in Down syndrome pregnancies of 0.79 multiples of median (MoM).13 More recently, Nicolaides et al. 14 observed the first trimester AFP median MoM to be 0.78 in 65 cases of Down syndrome.