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Lookup NU author(s): Dr Gareth RichardsORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
The sex difference of the 2D:4D digit ratio (female > male)–a proposed marker for prenatal testosterone exposure—is well established. Studies suggest it already exists in utero and is of moderate effect size in adulthood. However, evidence for the claim that 2D:4D reflects prenatal androgen action is limited, and the sex difference may exhibit lability during child- hood. In the present study, 244 mothers were recruited in the course of an amniocentesis examination (performed between gestational weeks 14 and 18). Prenatal testosterone (T) and estradiol (E) levels were determined from amniotic fluid for boys and girls. The majority (97.4%, n = 114) of available female T levels (n = 117) were found below the level of quantifi- cation. Therefore, only male amniotic fluid data (n = 117) could be included for the analysis of associations between amniotic sex hormones (T levels and T to E ratio (T/E)) and 2D:4D. The families were then invited to each of the five consecutive follow-ups (ages: 5, 9, 20, 40, and 70 months) where children’s 2D:4D was measured for both hands. The alternative marker D[r-l] reflects the directional asymmetry of 2D:4D (right subtracted by left 2D:4D) and was subsequently calculated as an additional measure for prenatal T exposure. No signifi- cant correlations between amniotic T or the T/E ratio (measured between week 14 and 18 of gestation) with 2D:4D respectively D[r-l] were observed for any time point. There was a signif- icant sex difference (females > males) and a significant age effect with moderate correla- tions of 2D:4D between time points. 2D:4D increased between 20 and 40 months and between 40 and 70 months of age. The findings raise questions regarding the applicability of 2D:4D as a marker for prenatal androgen action and are discussed in terms of the reliability of obtained digit ratio data as well as in terms of the developmental timing of amniocentesis.
Author(s): Ernsten L, Körner LM, Schaper ML, Lawrenz J, Richards G, Heil M, Schaal NK
Publication type: Article
Publication status: Published
Journal: PLoS ONE
Year: 2023
Volume: 18
Issue: 3
Online publication date: 23/03/2023
Acceptance date: 07/02/2023
Date deposited: 26/03/2023
ISSN (electronic): 1932-6203
Publisher: Public Library of Science
URL: https://doi.org/10.1371/journal.pone.0282253
DOI: 10.1371/journal.pone.0282253
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