title: Unconjugated estriol as maternal serum marker for the detection of Down syndrome pregnancies.
abstract: The effectiveness of unconjugated estriol (uE3) as a serum marker for the detection of Down syndrome (DS) during the 2nd trimester of pregnancy was evaluated. A population of 18,764 normal singleton pregnancies was screened for alpha-feto-protein and human chorionic gonadotropin. In 9,311 women, uE3 was added. Using a risk of 1:250 at term as a cutoff value, the false-positive rates were 4.1 and 4.3% without and with uE3, respectively. The detection rates in 47 DS serum samples, some of which were studied retrospectively, were 66% without uE3 and 57% with uE3. In 12 of 25 younger women and in 19 of 22 older women, DS was detected without uE3. The uE3 contributed to the detection of 4 additional DS pregnancies (1 in the young and 3 in older women). On the other hand, 8 DS pregnancies (3 in younger women and 5 in older women) escaped detection. In our sample the addition of uE3 lowered the detection rate of DS pregnancies with only a small and insignificant effect on the false-positive rate. Our results call for special caution in the addition of markers for risk calculations. We suggest that pregnancies with a calculated risk of > 1:250 following maternal serum alpha-fetoprotein and human chorionic gonadotropin markers tests should be regarded as high-risk pregnancies, even in cases in whom the addition of uE3 lowers the risk beneath the cutoff value.
authors.affiliation: Simon Winter Institute of Human Genetics, Bnai Zion Medical Center, Technion, Haifa, Israel.
authors.forename: M
authors.initials: M
authors.lastname: David
authors.forename: R
authors.initials: R
authors.lastname: Merksamer
authors.forename: N
authors.initials: N
authors.lastname: Israel
authors.forename: H
authors.initials: H
authors.lastname: Dar
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004314:Down Syndrome / Q000175:diagnosis*; D004964:Estriol / Q000097:blood*; D005260:Female; D006801:Humans; D008423:Maternal Age; D008431:Maternal-Fetal Exchange / Q000502:physiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis / Q000379:methods*
chemical_list: D015415:Biomarkers; D004964:Estriol