Ulrike Ehlert

Context Sex steroids (SS) typically rise during pregnancy and decline after birth, but no consistent reference values exist for these hormonal courses. We aimed to establish an overview of SS secretion patterns during the peripartum and to better understand how SS contribute to maternal and fetal pathologies. Evidence acquisition A systematic literature search was conducted in accordance with the PRISMA guidelines using PubMed, Cochrane Library, and PsycINFO. Additionally, we conducted a supplementary manual search of references. Observational studies published in English and assessing estradiol, progesterone, and testosterone over the course of the peripartum in physically healthy female subjects were included, without restrictions on year of publication. Extracted data were analyzed descriptively and visually. Evidence synthesis SS increase progressively during pregnancy, with an extremely wide range of reported concentrations, especially in the third trimester. In fact, reported concentrations varied up to 5000-fold at comparable measurement time points. Conclusions A comprehensive understanding of the influence of SS levels on associated maternal and fetal pathologies is currently hindered by 2 main factors. First, reported SS levels vary widely during the peripartum period. Second, the current state of knowledge on how SS are associated with pathologies in mothers and babies is largely based on correlational studies, and causality thus remains unclear. Consequently, we recommend the development of a systematic reference framework that follows the suggestions presented in this review. This would enable the establishment of SS reference values for a healthy population, resulting in the possibility to draw conclusions about deviations and related pathologies.