Alpha-fetoprotein, vaginal bleeding and pregnancy risk.

To assess the interrelation between maternal serum alpha-fetoprotein (MSAFP) levels and vaginal bleeding as a combined pregnancy risk factor, we studied 6829 singleton pregnancies without fetal malformations during the second trimester. The predictive powers of the two risk factors, analysed separately, are consistent with published reports in relation to fetal death and low birthweight. Until now, however, these two risk factors have not been analysed together. The present study demonstrates that MSAFP and vaginal bleeding are largely independent of each other as predictors of fetal death, relative risks being 0.7 (MSAFP less than 0.7 multiples of the median (MoM), vaginal bleeding absent), 3.5 (MSAFP less than 2.0 MoM vaginal bleeding present), 5.8 (MSAFP greater than or equal to 2.0 MoM, vaginal bleeding absent), and 12.6 (MSAFP greater than or equal to 2.0 MoM, vaginal bleeding present). Corresponding risks for low birthweight are: 0.7, 1.8, 2.5 and 1.6 (mean birthweights in the four categories are 3516 g, 3407 g, 3238 g, and 3176 g).