title: Maternal serum steroid levels are unrelated to fetal sex: a study in twin pregnancies.
abstract: Increased prenatal exposure to testosterone (T) in females of an opposite-sex (OS) twin pair may have an effect on the development of sex-typical cognitive and behavioral patterns. The prenatal exposure to T due to hormone transfer in OS twin females may occur in two ways, one directly via the feto-fetal transfer route within the uterus, the other indirectly through maternal-fetal transfer and based in the maternal-fetal compartment. Although some studies in singletons indeed found that women pregnant with a male fetus have higher T levels during gestation than women pregnant with a female fetus, many other studies could not find any relation between the sex of the fetus and maternal serum steroid levels. Therefore at present it is unclear whether a pregnant woman bearing a male has higher levels of T than a woman bearing a female. Up to this point, no-one has investigated this issue in twin pregnancies. We examined the relationship between maternal serum steroid levels and sex of fetus in 17 female-female, 9 male-male and 29 OS twin pregnancies. No differences were observed between the maternal serum steroid levels of women expecting single-sex and mixed-sex offspring. It is concluded that the source of prenatal T exposure in females probably comes from the fetal unit, which is the direct route of fetal hormone transfer.
authors.affiliation: Department of Child and Adolescent Psychiatry, University Medical Center Utrecht, and the Rudolf Magnus Institute of Neuroscience, the Netherlands. celina_cohen@yahoo.com
authors.forename: Celina C C
authors.initials: CC
authors.lastname: Cohen-Bendahan
authors.forename: Stephanie H M
authors.initials: SH
authors.lastname: van Goozen
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
authors.forename: Peggy T
authors.initials: PT
authors.lastname: Cohen-Kettenis
mesh_terms: D000328:Adult; D000735:Androstenedione / Q000097:blood; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D005330:Fetofetal Transfusion / Q000097:blood; D005333:Fetus; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000097:blood*; D011374:Progesterone / Q000097:blood; D012723:Sex; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood; D014427:Twins
chemical_list: D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D000735:Androstenedione; D011374:Progesterone; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate