The effect of fetomaternal bleeding on the risk of adverse pregnancy outcome in patients with elevated second-trimester maternal serum α-fetoprotein levels

Objective: Unexplained maternal serum α-fetoprotein elevation has been associated with an increased risk of intrauterine growth retardation, preterm delivery, and intrauterine fetal death. The purpose of this study was to determine whether patients with evidence of recent fetomaternal bleeding as a cause of elevated maternal serum α-fetoprotein level are at a lower risk for adverse pregnancy outcome than those without such evidence. Study Design: Patients with elevated maternal serum α-fetoprotein levels who had a singleton viable fetus without ultrasonographically detectable anomalies were offered inclusion in this study. Study participants had blood drawn for fetal cell analysis before amniocentesis. The pregnancy outcomes of patients with evidence of fetomaternal bleeding were compared with those of patients without. Results: Of 229 patients, 109 (47.6%) had evidence of fetomaternal bleeding as a possible cause of elevated maternal serum α-fetoprotein. Of these, 86 (78.9%) had a normal pregnancy outcome compared with 84 of 120 (70.0%) with a negative stain for fetal cells (p not significant). There was no significant difference in the incidence of preterm delivery (14 [12.8%] vs 15 [12.5%]), intrauterine growth retardation (5 [4.6%] vs 9 [7.5%]), or intrauterine fetal death (4 [3.7%] vs 8 [6.6%]) when patients with a positive stain for fetal cells were compared with those with a negative stain. Conclusion: Among patients with elevated maternal serum α-fetoprotein levels, those with evidence of recent fetomaternal bleeding do not appear to be at decreased risk for adverse pregnancy outcome compared with those without such evidence.