A 2005 study compared contraceptive use, sexual behaviors, and reproductive health outcomes among young adults and teens given emergency contraception (EC) to keep on hand to those given instructions on how to get it at a pharmacy or clinic.¹ A total of 2117 women aged 15-24 participated in the two-year study, conducted at four family planning clinics in the San Francisco area. Participants were interviewed, tested for pregnancy and STDs, and given information about EC as well as using condoms to protect against STDs at the time of enrollment; six months later, researchers administered questionnaires, did a second round of tests, and reviewed medical charts.

What was the purpose of the study?

What were the study's key findings?

Did the study find differences in emergency contraception use between young adults and teens who had it on hand and women who had to get it from a clinic or pharmacy?

Did the study find that having EC on hand changed use of regular contraception or increased sexual risk behavior among young adults and teens?

Were women who had EC on hand more likely to contract an STD?

Did the study find differences in pregnancy rates?

Do the pregnancy rate findings undermine claims that increasing access to emergency contraception (such as making it an over-the-counter drug) will improve public health?

How does this study differ from previous research?

What are the limitations of the study?

What was the purpose of the study?

Researchers at the University of California at San Francisco sought to better understand the impact of increased access to emergency contraception on important reproductive health outcomes, including STDs. The study was designed specifically to determine whether providing emergency contraception in advance or directly at a pharmacy would affect EC use or rates of STD infection or pregnancy among young adults and teens. The study also analyzed whether advance provision and pharmacy access affected use of contraception and condoms as well as sexual behaviors (frequency of intercourse, including unprotected sex, and number of sexual partners).

What were the study’s key findings?

Young adults and teens who had EC on hand were two times as likely to use back-up birth control than women who had to get the product from a pharmacy or a clinic (the "control group" in the study), even though rates of unprotected sex were similar for all three groups in the study. Neither advance provision nor pharmacy access undermined women’s use of regular contraceptive methods, including condoms, or increased sexual risk behaviors – and STD rates for women with increased EC access were comparable to the control group. There was no immediate, significant decline in unintended pregnancy rates among women in the advance provision or pharmacy access groups, a finding researchers believe reflects the fact that many women who were at risk still did not use back-up birth control.

Did the study find differences in emergency contraception use between young adults and teens who had it on hand and women who had to get it from a clinic or pharmacy?

Yes. Young adults and teens who were given three doses of EC in advance were almost twice as likely to use it at least once, compared to the control group of women who had to return to the clinic for it. At the same time, women who were given detailed instructions on how to obtain EC directly from a pharmacy were no more likely than the control group to use back-up birth control – indicating that requiring women to go to either a pharmacy or a clinic remains a barrier to EC use. Only a small fraction of women in either the advance provision or pharmacy access group used EC more than once.

Did the study find that having EC on hand changed use of regular contraception or increased sexual risk behavior among young adults and teens?

No. There were no significant differences in patterns of birth control or condom use or sexual behaviors by study group. Young adults and teens who had EC on hand or who had instructions on how to get it directly from a pharmacy were no more likely to miss a pill, switch birth control methods, or forego using a condom than women in the clinic access group. Frequency of intercourse, amount of unprotected sex, and number of sexual partners were also roughly equivalent among women in the advance provision, pharmacy access, and clinic control groups.

Were women who had EC on hand more likely to contract an STD?

No. Young adults and teens who received EC in advance or pharmacy access instructions had STD rates comparable to the clinic access control group. Overall, twelve percent of women in the study acquired an STD (chlamydia and genital herpes were identified through testing, self-reports, and chart reviews; gonorrhea, genital warts, trichomonas, and pelvic inflammatory disease were assessed through questionnaires and medical records).

Did the study find differences in pregnancy rates?

No. Overall, eight percent of study participants became pregnant – a slightly lower rate than the 10 percent researchers had anticipated based on previous studies. There were no significant differences in pregnancy rates between the advance provision, pharmacy access, or clinic control groups. Not surprisingly, pregnancy rates were higher among women who reported more acts of unprotected sex. Since incidents of unprotected sex were consistent across all three groups of women, the pregnancy findings underscore the need to encourage consistent contraception and EC use among women at risk for unintended pregnancy.

Do the pregnancy rate findings undermine claims that increasing access to emergency contraception (such as making it an over-the-counter drug) will improve public health²?

No. Actually, the findings of this study argue for an even greater national commitment to removing barriers to women’s use of emergency contraception and regular birth control methods. According to the UCSF researchers, women in the study were at a relatively high risk for pregnancy: More than a third (37.5%) reported engaging in unprotected sex at least "some of the time" during their six-month enrollment period, and only half of them (47%) reported using emergency contraception. Not surprisingly, women who reported having unprotected sex accounted for nearly three-quarters (73%) of the pregnancies. The UCSF researchers note that under-use of emergency contraception could account for the lack of an immediate, statistically significant difference in pregnancy rates (only 29% of all women in the study, including 37% of women in the advance provision group reported using EC). At the same time, the study shows that maintaining restrictions on emergency contraception – such as the prescription requirement – exacerbates under-use.

How does this study differ from previous research?

While several other studies examined the impact of advance provision of EC – and found it improves back-up birth control use – the UCSF study is the first to also evaluate whether pharmacy access influences women’s EC use (California is one of six states that now allow women to get this product directly from a pharmacist). In addition, UCSF researchers are the first to test whether improving EC access could increase STD risk by affecting a host of sexual behaviors – including frequency of intercourse, amount of unprotected sex, and number of partners – by correlating data from women’s own reports with outcomes measured using both biological markers (tests) and medical chart reviews. Previous studies found no association between advance provision of EC and increases in unprotected sex or less condom use based only on self-reporting.

What are the limitations of this study?

Several factors limit the ability of researchers to relate the results of this study to the general population of women [aged 15-24] in the U.S. First, there was a treatment "cross over" effect even though every participant was randomly assigned to one of three groups – advance provision, pharmacy access, or clinic access (two-thirds of study participants reported obtaining EC at last use consistent with their assigned treatment group). In addition, researchers found that women assigned to the clinic access control group had higher rates of EC use than controls in other studies. Finally, they note that the young adults and teens in the study visited a family planning clinic and were counseled about back-up birth control, information and services that all women in their age group may not receive.

¹ Raine T. et al, Increased Access to Emergency Contraception and Impact on Pregnancy and STIs: A Randomized Controlled Trial, Journal of the American Medical Association, 2005;293:54-62.

² Researchers have estimated that widespread awareness and use of emergency contraception could prevent as many as half of the roughly 3 million unintended pregnancies that occur each year in the U.S. These projections reflect what would happen if three-quarters of women who experience contraceptive failure and all women who had unprotected sex were to use emergency contraception, given that studies show EC reduces the chances of pregnancy after a single act of unprotected intercourse by at least 75 percent. Trussell J, et al, Emergency Contraceptive Pills. “A Simple Proposal To Reduce Unintended Pregnancies,” Family Planning Perspectives 1992, 24:269-273.