Pregnancy outcome for women with very low levels of maternal serum unconjugated estriol on second-trimester screening

OBJECTIVE: Our purpose was to assess pregnancy outcome for women whose second-trimester triple screen results revealed very low unconjugated estriol levels. STUDY DESIGN: Of 44,146 women screened for α-fetoprotein, human chorionic gonadotropin, and unconjugated estriol, a group of women with isolated very low unconjugated estriol levels were selected as the study group. Pregnancy outcome was obtained by contacting the referring physicians. RESULTS: During the study period 62 women had unconjugated estriol levels at or below the sensitivity of the assay. Fetal detah was the most common explanation, accounting for 37.1% of cases. Six cases of early death followed uneventful prenatal visits. Eighteen women had unexplained very low unconjugated estriol levels. Of these 18, four cases of placental sulfatase deficiency were diagnosed. Sixteen of these 18 women gave birth to male infants (p = 0.03). CONCLUSION: A very low unconjugated estriol level in the second trimester is associated with increased risk for early death and placental sulfatase deficiency.