Thursday February 21 2008
Women who expirience vaginal orgasms have a thicker urethrovaginal space
“Scientists find the G-spot but not all women have it” is the headline in The Independent. The article it relates to says scientists have found “a thickened area of tissue in those who said they had experienced vaginal orgasms, but not in those who had not”. Many other newspapers and news sources, including the New Scientist, cover the story that an Italian scientist believes he may have found the female G-spot, an elusive and controversial pleasure point, which some women say triggers powerful vaginal orgasms. The Times suggests that this research may also “explain why so many women have searched for their G-spot in vain”, suggesting that not all of them have one.
This was a small study of 20 healthy Italian volunteers who reported their own experiences of orgasm and agreed to have an ultrasound examination measuring the thickness of the tissue between their vagina and urethra, known as the urethrovaginal space. The study reported that the differences in the thickness of the tissue correlated with whether or not the women reported the ability to have a vaginal orgasm. However, this research doesn’t make clear any link between tissue thickness and vaginal orgasm, or the direction of causation (i.e. which factor causes which). If the G-spot does exist, its exact location is not revealed by this study.
Where did the story come from?
Dr Giovanni Gravina and colleagues from the Universities of L’Aquila and Rome, Italy, carried out this research. The study was partly supported by the Italian Ministry of Research and Education and an unrestricted grant from the drug company, Pfizer. It was published in the peer-reviewed medical journal: Journal of Sexual Medicine.
What kind of scientific study was this?
This was a cross-sectional study that compared two groups of women who were not allocated to groups in a randomised or controlled way. The researchers invited 20 women who were in the healthy control arm of a previous study of bladder-flow rates and control in women. Of the 37 possible volunteers in this study, the researchers selected those who were in stable, heterosexual relationships and who reported having sexual intercourse at least twice a week over the previous six months. They also scored highly (at least four or five out of five) on three specific questions asked by a sexologist: “How often do you reach orgasm?”, “How difficult is it for you to reach orgasm?” and “How satisfied are you with your ability to reach orgasm?”. It is not stated whether the researcher asking these questions was male or female.
For the next part of the study a male investigator asked further questions at a separate time and the answers were not revealed to the other investigators. He asked “Have you ever experienced a vaginal orgasm?” and responses were categorised as yes (at least once in the past month) or no (never).
A 20-minute vaginal ultrasound examination was performed halfway through the women’s menstrual cycle by a female investigator who was unaware of the answers given to the previous questions. The investigator measured the thickness of tissue between the vagina and the urethra (the tube leading from the bladder though which urine passes) at three points along its length. They called this the urethrovaginal space. They then analysed the differences between the two groups for statistical significance.
What were the results of the study?
All the women in the two groups were of a similar age (average 32–34 years). The nine women who reported an ability to achieve a vaginal orgasm had a urethrovaginal space that was on average 12.4mm thick. The 11 women without this ability had a thinner space, on average 10.4mm thick. The researchers found that this difference was statistically significant.
What interpretations did the researchers draw from these results?
The researchers conclude that “the measurement of the space within the anterior vaginal wall by ultrasonography is a simple tool to explore anatomical variability of the human clitoris-urethrovaginal complex, also known as the G-spot.” They claim to have correlated the thickness of this space with the ability to experience vaginal orgasm.
What does the NHS Knowledge Service make of this study?
Any associations or links demonstrated in cross-sectional studies of this sort should be considered tentative for a number of reasons:
- The self-reporting of vaginal orgasm may be subject to a reporting bias. This means that those who respond by answering “no” may differ in some way from those who answer “yes”, other than the nature of their orgasm, for example, they may not have understood the question or have been offended. These aspects are not reported.
- The ‘normal’ range of urethrovaginal space thickness is not given in this study, so it is not possible to exclude the possibility that either group had thinner or thicker spaces based on other physiological differences or medical conditions.
- The direction of any link shown cannot be determined from a cross-sectional study design. It’s possible that women who report vaginal orgasms develop thicker vaginal muscles.
- The sexual experiences of Italian women and men may differ from those of other nationalities.
Sir Muir Gray adds...
Further research is necessary is what the researchers usually say; I am sure there will be a call for more research on this topic.