Maternal serum alpha-fetoprotein and spontaneous abortion.

The relationship between spontaneous abortion and maternal serum alpha-fetoprotein (AFP) levels was investigated between 9 and 25 weeks of pregnancy. Seven out of 126 (5-6 per cent) women who had spontaneous abortions had raised maternal serum AFP levels at their antenatal booking visit compared to 4 out of 247 (1-6 per cent) control patients who were delivered of single liveborn infants, a statistically significant differences. The raised AFP concentrations were, however, associated with spontaneous abortion only if the serum samples had been taken immediately before, or at sometime after the abortion was first clinically suspected. This suggests that high levels do not predict the development of abortion in women who have not already threatened to abort. It is therefore unlikely that women who have not already threatened to abort. Therefore, when maternal serum AFP levels are used to screen for fetal neural tube defects, women referred for a diagnostic amniocentesis on account of a high level are unlikely to have been selected on the basis of a tendency to abort.