Researchers in the US found that women who were overweight were more likely to report ever having sexual intercourse with a man, but apart from that women’s sexual behavior did not vary by body mass index.

The study was by researchers at the Department of Obstetrics and Gynecology, University of Hawaii, Honolulu, Hawaii, and other research centres in the US and is published in the journal Obstetrics & Gynecology.

For the study, the researchers looked at data from the 2002 National Survey of Family Growth, which interviewed a nationally representative cross section of women aged 15 to 44 years regardless of reproductive health status. The height and weight measures were also self-reported.

The researchers looked at the links between body mass index and a number of sexual behavior measures, including orientation, age at first intercourse, ever having had sex with a male partner, the number of partners and frequency of intercourse. The sexual behavior was categorized by body mass index (BMI) groups: Normal (under 25 kg/m2), overweight (25 to 30 mg/m2) and obese (over 30 kg/m2).

The results showed that:

  • BMI was not significantly linked to sexual orientation, age at first intercourse, frequency of heterosexual intercourse, and the number of lifetime or current male partners.
  • Overweight and obese women were more likely to report ever having had sexual intercourse with a male partner (p under 0.001).
  • 92 per cent of overweight women reported ever having had sexual intercourse with a male partner compared with 87 per cent of women of normal BMI.
  • This figure was unaffected by adjustments for age and type of residence.

The authors concluded that:

“With the exception of ever engaging in sexual intercourse with a man, sexual behavior differs little between women of different body mass indices.”

Lead author Dr Bliss Kaneshiro an assistant professor at the University of Hawaii told the press that:

“These results were unexpected and we don’t really know why this is the case.”

Kaneshiro first presented the results of this study at the American College of Obstetricians and Gynecologists (ACOG) 56th Annual Clinical Meeting in May this year where she won first prize for the paper.

At the presentation Kaneshiro said that some studies have suggested that women of higher BMI have a higher risk of unwanted pregnancy than women of normal BMI and that although factors like use and effectiveness of contraception may play a part it could also be explained by sexual behavior.

She said the study was important because there could be bias on the part of doctors advising overrweight and obese women who may not give them the same advice about pregnancy and STD prevention as they do women with a more normal BMI.

“This study indicates that all women deserve diligence in counseling on unintended pregnancy and sexually transmitted disease prevention, regardless of body mass index,” she said.

Click here for Abstract.

“Body Mass Index and Sexual Behavior.”
Bliss Kaneshiro, Jeffrey T. Jensen, Nichole E. Carlson, S. Marie Harvey, Mark D. Nichols, Alison B. Edelman.
Obstetrics & Gynecology, 2008;112:586-592. Sources: Journal Article, UPI, MNT archives.

Written by: Catharine Paddock, PhD.