title: Fetal sex differences in human chorionic gonadotropin fluctuate by maternal race, age, weight and by gestational age.
abstract: Circulating levels of the placental glycoprotein hormone human chorionic gonadotropin (hCG) are higher in women carrying female v. male fetuses; yet, the significance of this difference with respect to maternal factors, environmental exposures and neonatal outcomes is unknown. As a first step in evaluating the biologic and clinical significance of sex differences in hCG, we conducted a population-level analysis to assess its stability across subgroups. Subjects were women carrying singleton pregnancies who participated in prenatal and newborn screening programs in CA from 2009 to 2012 (1.1 million serum samples). hCG was measured in the first and second trimesters and fetal sex was determined from the neonatal record. Multivariate linear models were used to estimate hCG means in women carrying female and male fetuses. We report fluctuations in the ratios of female to male hCG by maternal factors and by gestational age. hCG was higher in the case of a female fetus by 11 and 8% in the first and second trimesters, respectively (P<0.0001). There were small (1-5%) fluctuations in the sex difference by maternal race, weight and age. The female-to-male ratio in hCG decreased from 17 to 2% in the first trimester, and then increased from 2 to 19% in the second trimester (P<0.0001). We demonstrate within a well enumerated, diverse US population that the sex difference in hCG overall is stable. Small fluctuations within population subgroups may be relevant to environmental and physiologic effects on the placenta and can be probed further using these types of data.
authors.affiliation: 1Department of Epidemiology,Graduate School of Public Health,University of Pittsburgh,Pittsburgh,PA,USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Adibi
authors.affiliation: 1Department of Epidemiology,Graduate School of Public Health,University of Pittsburgh,Pittsburgh,PA,USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Lee
authors.affiliation: 3California Department of Public Health,Genetic Disease Screening Program,Program Development and Evaluation,Richmond,CA,USA.
authors.forename: S
authors.initials: S
authors.lastname: Saha
authors.affiliation: 4Statistical Analysis Core,UCSF Pepper Center,University of California,San Francisco,CA,USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Boscardin
authors.affiliation: 5Bioinformatics Core,Clinical Translation and Science Institute,University of Pittsburgh,Pittsburgh,PA,USA.
authors.forename: A
authors.initials: A
authors.lastname: Apfel
authors.affiliation: 3California Department of Public Health,Genetic Disease Screening Program,Program Development and Evaluation,Richmond,CA,USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Currier
mesh_terms: D006063:Chorionic Gonadotropin / Q000097:blood*; D005260:Female; D020567:Fetal Weight; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D011264:Pregnancy Trimesters / Q000097:blood; D012727:Sex Characteristics
chemical_list: D006063:Chorionic Gonadotropin
keywords: placental hormones; pregnancy; sexual dimorphism