A failing pregnancy may present with vaginal bleeding and the passage of fetal tissue. Alpha-fetoprotein (AFP) concentration in fetal serum is at least 1000 times higher than it is in maternal serum. The objective of this study was to determine if vaginal blood mixed with fetal tissue has a relatively higher concentration of AFP than vaginal blood in the case of a threatened abortion.
The study group was women with incomplete abortion or with missed abortion that started to have vaginal bleeding. The control group was women with threatened abortion (ie, not passing fetal tissue and with a fetal heartbeat). In each group, every woman's maternal serum AFP concentration was compared to the AFP concentration in the vaginal blood. Values were expressed as mean±SEM. Paired t
test was used.
In the study group (17 women), the mean AFP concentration in blood sampled from the vagina was 17,043±11,048 ng/mL vs 11±2.7 ng/mL in the maternal serum (P
<.001). In the control group (9 women), the mean AFP concentration in the blood sampled from the vagina was 71 ± 18 ng/mL vs 112 ± 32 ng/mL in the maternal serum (P
=.1). In the study group, the AFP concentration in the vaginal blood was 8–8,620 times higher than in the maternal serum, whereas in the control group the ratio was around 1 (range 0.37–1.36).
AFP concentration in vaginal blood that is at least 8 times higher than AFP concentration in maternal serum may indicate a passage or dissolving fetal tissue (ie, pregnancy failure).