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The effect of fetal gender on second‐trimester maternal serum inhibin‐A concentration
Author(s) -
Hang Lam Yung,
Hoi Yin Tang Mary
Publication year - 2001
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.120
Subject(s) - fetus , gestation , medicine , down syndrome , obstetrics , pregnancy , endocrinology , biology , genetics , psychiatry
Second‐trimester serum inhibin‐A is increasingly used as a fourth marker in addition to the triple test to screen for Down syndrome. We investigated whether fetal gender had an effect on serum inhibin‐A concentration. A retrospective analysis was done on 316 normal pregnancies and 48 Down syndrome pregnancies in which maternal serum inhibin‐A assays were performed between 15 and 20 weeks of gestation and in which the fetal sex was known. The median inhibin‐A MoM (95% CI) for normal pregnancies in the presence of a male fetus was 0.93 (range 0.88–1.03). This was significantly lower than that in the presence of a female fetus (median MoM=1.04). The gender difference was not observed in the Down syndrome pregnancies. The increased inhibin‐A concentration would lead to a 2.3‐fold higher false‐positive rate in the presence of a female fetus (10.6% vs 4.6%; p <0.05, Chi‐square test). Because of the small number of cases studied, the results need to be substantiated by a larger series. If the gender effect is confirmed, adjustment for fetal sex may be necessary when inhibin‐A is used as a screening marker. Copyright © 2001 John Wiley & Sons, Ltd.