Symmetrical women have higher potential fertility

Jasienska, Grazyna; Lipson, Susan F.; Ellison, Peter T.; Thune, Inger; Ziomkiewicz, Anna

doi:10.1016/j.evolhumbehav.2006.01.001

« PreviousEvolution & Human Behavior
Volume 27, Issue 5 , Pages 390-400, September 2006

Symmetrical women have higher potential fertility

Grazyna Jasienska
- Department of Epidemiology and Population Studies, Jagiellonian University, Collegium Medicum, 31-531 Krakow, Poland
- Radcliffe Institute for Advanced Study, Harvard University, Cambridge, MA 02138, USA
- Corresponding author. Radcliffe Institute for Advanced Study, Harvard University, 34 Concord Ave., Cambridge, MA 02138, USA. Tel.: +1 617 495 8182; fax: +1 617 495 8136.
Susan F. Lipson
- Department of Anthropology, Harvard University, Cambridge, MA 02138, USA
Peter T. Ellison
- Department of Anthropology, Harvard University, Cambridge, MA 02138, USA
Inger Thune
- Institute of Community Medicine, University of Tromso, Tromso, Norway
- Ulleval University Hospital, Oslo, Norway
Anna Ziomkiewicz
- Department of Epidemiology and Population Studies, Jagiellonian University, Collegium Medicum, 31-531 Krakow, Poland

Received 2 November 2005; accepted 10 January 2006. published online 13 March 2006.

Abstract

Fluctuating asymmetry (FA) is believed to reflect developmental stability and thus may serve as a marker of the biologic quality of individuals. To test the hypothesis that degree of FA is related to a woman's potential fertility, we measured finger length together with levels of estradiol in saliva samples collected daily for an entire menstrual cycle in 171 Polish urban and rural women. We show that women who are more symmetrical, as assessed by the degree of inequality in the fourth-digit length of their right and left hands, have 13% higher average levels of estradiol over the menstrual cycle than less symmetrical women (19.4 and 17.1 pmol/l, respectively; p=.0001). Among urban women, mid-cycle levels of estradiol were 28% higher in the symmetrical group than in the asymmetrical group. Because higher hormone levels in women may lead to a substantial rise in the probability of conception, low FA may therefore be associated with increased fertility.

Keywords: Fluctuating asymmetry, Health, Hormones, Menstrual cycle, Premenopausal women