Second-trimester maternal serum marker screening: Maternal serum α-fetoprotein, β-human chorionic gonadotropin, estriol, and their various combinations as predictors of pregnancy outcome

Abstract

Objective: We evaluated the value of all 3 common biochemical serum markers, maternal serum α-fetoprotein, β-human chorionic gonadotropin, and unconjugated estriol, and combinations thereof as predictors of pregnancy outcome. Study Design: A total of 60,040 patients underwent maternal serum screening. All patients had maternal serum α-fetoprotein measurements; β-human chorionic gonadotropin was measured in 45,565 patients, and 24,504 patients had determination of all 3 markers, including unconjugated estriol. The incidences of various pregnancy outcomes were evaluated according to the serum marker levels by using clinically applied cutoff points. Results: In confirmation of previous observations, increased maternal serum α-fetoprotein levels (>2.5 multiples of the median) were found to be significantly associated with pregnancy-induced hypertension, miscarriage, preterm delivery, intrauterine growth restriction, intrauterine fetal death, oligohydramnios, and abruptio placentae. Increased β-human chorionic gonadotropin levels (>2.5 multiples of the median [MoM]) were significantly associated with pregnancy-induced hypertension, miscarriage, preterm delivery, and intrauterine fetal death. Finally, decreased unconjugated estriol levels (<0.5 MoM) were found to be significantly associated with pregnancy-induced hypertension, miscarriage, intrauterine growth restriction, and intrauterine fetal death. As with increased second-trimester maternal serum α-fetoprotein levels, increased serum β-human chorionic gonadotropin and low unconjugated estriol levels are significantly associated with adverse pregnancy outcomes. These are most likely attributed to placental dysfunction. Conclusion: Multiple-marker screening can be used not only for the detection of fetal anomalies and aneu-ploidy but also for detection of high-risk pregnancies. (Am J Obstet Gynecol 1999;181:968-74.)