Oct. 31, 2008 -- Can women tip off men that they are fertile by subtle changes in their voice?
A new study looks into a possible link between how a woman's voice changes as she reaches her most fertile time of the month.
This study was co-authored by Gregory Bryant and Martie Haselton at the University of California, Los Angeles.
They got together 69 women, average age of 20, all of whom were having regular periods and not using hormonal birth control.
Researchers then collected two sets of voice samples from the participants.
One voice recording was made when women were at their peak fertile time. Another was made when they were at the low end of the fertility cycle.
All of the women were asked to say the sentence "Hi, I'm a student at UCLA." They were also told to utter a string of vowel sounds, like "eh" in "bet."
It turns out that when the women were at their most fertile, the pitch of their voices went up significantly when compared to the recording made during the low fertile time.
But this happened only when they said the sentence, not when participants said vowel sounds.
That difference in pitch was greatest during women's most fertile time, the two days before ovulation. That "window" is when women have the highest probability of conceiving a child.
Study authors write in an article published with the findings that their work adds to a body of research showing that women may engage in subtle, unconscious behaviors during their most fertile times.
The authors cite previous research that found that women dress more attractively when they are ovulating and that exotic dancers make the most tips when they are most fertile.
Researchers write that it's possible that hormones swirling around during high fertile times affect how the voice sounds.
The study appears in the December 2008 issue of the journal Biology Letters.