Obese women who are not in a relationship are four times more likely to fall pregnant accidentally than women of a normal weight, despite having sex less often, a study has found.
The largest ever study into obesity and sexual health also found women who are unhealthily overweight are also 63% less likely to seek advice on contraception, two-thirds less likely to take the contraceptive pill and generally view sex as less important.
In addition, it was revealed that obese women were five times more likely to have met their partner online, and were more likely to have an obese partner than women of a healthy weight.
Furthermore, they were 29% less likely to report having had a sexual partner in the previous 12 months.
Obesity was also shown to have a significant impact on men, with obese men being 69% less likely to report more than one partner in the previous year compared with men of normal weight.
The study found they were almost three times more likely to report erectile dysfunction as men of a normal weight and were more likely to say they had picked up a sexually-transmitted infection.
The research, published online in the British Medical Journal (BMJ), involved more than 12,000 men and women in France.
But a British expert said the findings had far-reaching implications, and called for greater understanding of how obese people feel about their sex lives and the impact of obesity on health.
In an accompanying BMJ editorial, Dr Sandy Goldbeck-Wood, from the Sexual Problems Clinic at Camden and Islington Mental Health Trust in north London, said: “In particular, we need to know why obese women use less contraception and have more unwanted pregnancies despite having fewer sexual partners.”