Oestrogen good for keeping tabs on the competition

Women with higher levels of oestrogen can spot when another woman is ovulating, new evidence shows.

Research suggests men find a woman more attractive when she is ovulating but few studies have investigated whether other women react.

Now Swiss researchers say there is evidence to show that while women do not tend to find an ovulating woman more attractive, some may find her more threatening.

Results from their online study of 160 women suggest women with naturally higher levels of oestrogen are more in tune with another woman’s menstrual cycle and are better at determining when she is ovulating.

This suggests an evolutionary trait, say the researchers, as an ovulating woman would be deemed to pose a reproductive threat.

“Because gonadal hormones influence competitive behaviour, we examined whether oestradiol, testosterone and progesterone levels predict women’s choices,” write the researches in Biology Letters.

“The women found neither the late follicular nor the luteal version more attractive, however, naturally cycling women with higher oestradiol levels were more likely to choose the ovulatory woman as the one who would entice their date than women with lower oestradiol levels.”

The researchers, from the University of Bern, say these results imply a role of oestradiol when evaluating other women who are competing for reproduction.