Severity of Premenstrual Symptoms Predicted by Second to Fourth Digit Ratio.

Yoshiki Kaneoke,Toshio Shimokawa,Akihiko Iwahara,Tomohiro Donishi

doi:10.3389/fmed.2017.00144

Abstract

Women of reproductive age often experience a variety of unpleasant symptoms prior to the onset of menstruation. While genetics may influence the variability of these symptoms and their severity among women, the exact causes remain unknown. We hypothesized that symptom variability originates from differences in the embryonic environment and thus development caused by variation in exposure to sex hormones. We measured the second to fourth digit ratios (2D:4D) in 402 young women and investigated the potential relationships of this ratio premenstrual symptoms using a generalized linear model. We found that two models (one with two predictors such as both hands’ digit ratios and the other with the difference between the two digit ratios, Dr-l) were significantly different from the constant model as assessed by chi-square test. The right digit ratio and Dr-l were negatively related to the symptom scores, and the left digit ratio was related to the scores. When premenstrual symptoms were classified into eight categories, five categories, including pain, concentration, autonomic reaction, negative affect, and control were associated with the digit ratios and Dr-l. Behavioral changes and water retention were not predicted by them. Arousal was predicted by Dr-l. The right 2D:4D is thought to be determined by the balance of testosterone and estrogen levels during early embryogenesis and is not affected by postpartum levels of sex hormones, while the left 2D:4D might be affected by the other prenatal environmental factors. We conclude that the embryonic environment, including the relative concentration of sex hormones an embryo is exposed to, is associated with the severity of premenstrual symptoms once menarche is reached.

Highlights

Up to 90% of women of reproductive age experience discomfort related to their menstrual cycle, with 20–40% of women manifesting severe symptoms that meet the criteria for “premenstrual syndrome” (PMS) [1]
The one- and two-predictors models showed that the right 2D:4D was negatively related to the total score and symptom categories of pain, concentration, autonomic reaction, and control (Figures 2 and 3; Table 1)
The results suggest that the severity of such premenstrual symptoms is associated with prenatal sex hormones exposure: several lines of evidence summarized by Hönekopp et al [19] and Manning et al [36] suggest that the human digit ratio is affected by the magnitude of prenatal sex hormone exposure and the sensitivity of androgen receptors to testosterone

Summary

Introduction

Up to 90% of women of reproductive age experience discomfort related to their menstrual cycle, with 20–40% of women manifesting severe symptoms that meet the criteria for “premenstrual syndrome” (PMS) [1]. Some women develop central nervous system complaints and others develop symptoms in their peripheral organs that exhibit sensitivity to fluctuations in hormonal status and cause a variety of symptoms in response to environmental stress. One possibility is that the embryonic environment, exposure to different levels of sex hormones, may determine individual sensitivity to fluctuation of sex hormones in women of reproductive age by the so-called organizational effects [5]. We hypothesized that if premenstrual symptoms originate from the development of the brain and other organs that are thought to cause vulnerability to fluctuations in sex hormones in females, exposure to prenatal sex hormones might affect their severity

Methods

Results

Conclusion