title: Meta-analysis of sex difference in testosterone levels in umbilical cord blood.
abstract: This meta-analysis reviewed published literature comparing human male and female umbilical cord total testosterone (T) levels. A total of 18 studies using 1,229 samples from 602 male and 627 female newborns were analysed using the RevMan 5 statistical package. Analysis using the inverse variance method based on a random-effects model revealed significantly higher cord T in boys than girls at a moderate effect size (Hedges' g = 0.57). There was significant heterogeneity between the 18 studies, although the five studies using direct assays showed no heterogeneity. For studies using extraction and chromatography, those that combined T from arterial and venous cord blood found a larger sex difference than those using only cord venous samples (Hedges' g = 0.94 vs 0.32); this suggests umbilical cord venous T is of maternal/placental origin and arterial T is of fetal origin. The wide range of T values between studies suggests high cross-reactivity in the assay methods reviewed.
authors.affiliation: Department of Psychology, City University, University, London EC1V 0HB, UK. j.a.barry@city.ac.uk
authors.forename: J A
authors.initials: JA
authors.lastname: Barry
authors.forename: P J
authors.initials: PJ
authors.lastname: Hardiman
authors.forename: M R
authors.initials: MR
authors.lastname: Siddiqui
authors.forename: M
authors.initials: M
authors.lastname: Thomas
mesh_terms: D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010920:Placenta / Q000378:metabolism*; D011085:Polycystic Ovary Syndrome / Q000378:metabolism*; D011247:Pregnancy; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood*; D014469:Umbilical Arteries / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism
chemical_list: D013739:Testosterone