In findings being presented at the International Conference on Family Planning in Nusa Dua, Indonesia, researchers from the Johns Hopkins Bloomberg School of Public Health say that women of childbearing age in marriages or unions who use contraception are three times more likely to be having regular sexual intercourse than similar women who do not use contraception.

"We want women to have better, healthier, safer sex lives by separating sex from pregnancy and childbearing. Contraception does that," says study leader Suzanne Bell, MPH, a doctoral student at the Bloomberg School. "Knowing how often women have sex -- and what role contraception plays in that -- can give us a better understanding of how meeting our family planning goals of improving access and meeting demand might impact people's lives beyond decreasing lifetime fertility."

For their study, Bell and her co-author David Bishai, MD, PhD, a professor at the Bloomberg School, analyzed Demographic and Health Survey questionnaires completed since 2005 by more than 210,000 sexually active women of childbearing age in 47 countries. All women were married or in cohabiting relationships. Among other questions, the women were asked whether they had engaged in sexual intercourse during the previous four weeks and whether they were currently using contraception.

Of the women who were currently using contraception, 90 percent reported having sex in the previous four weeks. In contrast, of the women not using contraception, 72 percent reported having sex in the previous four weeks. Those most likely to have had sexual intercourse in the previous four weeks were women between the ages of 20 and 29, women with more education and those who wanted to have children in the next two years.

By country, the West African nation of Benin had the lowest proportion of married or cohabiting women reporting having had sex recently at 61 percent, followed by Lesotho in Southern Africa at 68 percent, whereas Jordan in the Middle East had the highest at 94 percent, preceded by Rwanda in East Africa at 92 percent.

While the frequency of sexual intercourse and use of contraception are linked, Bell cautions against assuming that improved access to contraception would lead to more frequent sexual intercourse. She says women have a variety of reasons for not using contraception -- and it is not only because they don't have access to it. Concerns about side effects and other health issues that could arise from the use of hormone-based contraception -- for example the misconception that contraception can cause infertility or cancer -- are oft-cited reasons for non-use. Findings suggest that some women who cannot or do not want to use contraception may be substituting less regular sex to reduce their risk of pregnancy. But many women also report they aren't using contraception because they are having infrequent sex, not the other way around.

Bell says that before modern contraception was widely accessible in Europe and the United States, birth rates were already on the decline, as couples likely engaged in periodic abstinence, withdrawal or other non-modern contraceptive methods to reduce fertility. The extent to which women and couples in the developing world may be using these traditional methods today is often overlooked in current measures of contraceptive demand, Bell says.

Researchers have long considered a concept of "unmet need" for family planning, which posits that sexually active women of childbearing age who do not wish to become pregnant in the next two years, if at all, need contraception. Bell says her research suggests that need may be more nuanced and that current estimates, which put unmet need at over 220 million in developing countries, actually overestimate contraceptive demand because many of these women with unmet need are not having regular or any sex.

"We need to put sex into conversations about family planning in order to understand how that factors into a woman's decision to use contraception or not," she says. "Risk of pregnancy is not uniform across users and non-users, as our results suggest."

Modern contraception presents an opportunity to reduce the risk of pregnancy without having to reduce sexual frequency, Bell adds. "Healthy sex lives are good for relationships but we often leave that out of conversations about the benefits of family planning," she says.

She says that contraceptive counseling is often inadequate in the developing world and women need better information about their contraceptive options to empower them to make the best decision on how to prevent unintended pregnancies.

If future research is able to establish that more available contraception actually increases the likelihood of engaging in more frequent sex, then increasing its availability "could mean good things for the sex lives of men and women worldwide," Bell says.

Adds Bishai, the senior author: "For too long development specialists told policymakers that investing in family planning would create prosperity for the next generation. Now it's time for a message focused on this generation. More family planning means more sex for married couples now."