Published on November 21st, 20130
How hormones influence the female sexual activity during a month?
Hormones stimulate women to have more sex during fertile periods, but practical concerns such as work and your partners wishes could have a more pronounced effect on the rate of female sexual activity.
These are the results of a new study on the unclear relationship between hormones and female sexuality. The research is the first to compare women with partners and single women. The study also included an impressive number of participants: 1,957 women, each of them repeatedly studied with ultrasound to determine exactly when they ovulate.
Previous research on sexuality and the menstrual cycle used less accurate methods such as measuring days from last menstruation to guessing when ovulation occurs, which led to disputable conclusions, explains Salvatore Caruso of the University of Catania . “They weren’t made very well“, says Caruso on older studies .
Many mammals come into heat when they are fertile, signaling their sexual interest. A horse, for example, produces a hormone-rich urine. The scent reveals a stallion that is ready to mate. Female baboon shows her red back side and from the point of view of the male, the bigger, the better.
In addition to these phases, these mammals are not interested in sex. People differ in this respect. Women ovulation is hidden (although they may provide accidental clues by the way they move, how they dress), and women have sex during the entire month, no matter if they recently ovulated or not.
However, research so far is not clear whether typical mammalian hormonal impulses influence human sexuality. Some studies have shown that women’s sexual activity are consistent throughout the menstrual cycle. Other research, however, revealed the possible correlation between hormone levels, ovulation and sexual interest.
The results were not clear, partly because ovulation is so discreet. Accurately measuring time when women ovulate makes a study a costly endeavor that requires a lot of time, which is why many researchers have resorted to the use of estimates.
Caruso and his colleagues decided to make the extra effort required. Between 2004 and 2001, they recruited 1,957 heterosexual women, excluding those who used hormonal contraceptives. About three quarters of the women were in a long term relationship (longer than six months). The other women were without a partner or had short-term relationships.
Women, who were aged between 18 and 40 years, researchers told their sexual histories and agreed to keep a diary of their sexual activity and moments of excitement for one month. During that month, the ovaries of women were studied three times with a transvaginal ultrasound. Before ovulation, an unfertilized egg develops into a follicle, visible as a small bump on the outside of the ovary. Ultrasound detect this follicle and recorded its bursts, releasing the egg, in a process called ovulation.
The researchers also tested the women’s blood before ovulation, during ovulation and after ovulation to measure hormone levels.
Scientists have discovered that women in relationships had some sexual activity (including masturbation) of 1.9 times per week on average, while single women had a sexual activity of 1.5 times per week. Women with partners were more likely to have sex on the weekend, highlighting the importance of the daily routine in sexuality - there is simply more time to be spent in bed on Saturday and Sunday.
“Probably the couple is affected by psychosocial factors more than the single woman, for example, family management and leisure of both the woman and the partners“, says Caruso .
However, hormones and the menstrual cycle appears to play a small role. As sexual activity increased so did the level of male hormones in the blood, of which testosterone is most known. Testosterone is usually raised during ovulation, but can vary from woman to woman during the menstrual cycle.
Single women, especially, had more sex during ovulation. This finding suggests that women without partners may be more affected than coupled women who are forced to take into account the partner’s needs and family responsibilities, says Caruso.
“Ovarian steroids may modulate sexual activity of women, but increases the likelihood that the sexual activity to occur more often when fertile than when not“, said the researcher, referring to the sex hormones like testosterone and estrogen.
Other research has shown that testosterone influences women’s interest in masturbation, but not necessarily interest in sex with a partner.
Caruso and his colleagues are now expanding their study to women using hormonal birth control, post-menopausal women and women with hormone disorders. The goal, he said, is to tease out how much hormones matter to a woman’s sexuality — and to what extent culture can override the biological influences.
Research results are published in the Journal of Sexual Medicine.