Maternal serum biochemical screening for pregnancy complications other than aneuploidy.

The link between a wide range of pregnancy complications and unexplained elevated mid-trimester levels of maternal serum alpha-fetoprotein (MSAFP) and maternal serum human chorionic gonadotrophin (MShCG), with its subunits, is becoming established. This link seems to be stronger when levels of both MSAFP and MShCG are elevated. In addition, it seems that the greater the change in levels of MSAFP or MShCG, or both, the greater the subsequent risk of pregnancy complications. By using these markers as a screening test it may be possible to identify high-risk pregnancies as early as 15 weeks' gestation and manage them more intensively.