Women who take birth control pills every day may soon be able to end their ongoing worry of: “Did I take my pill today?” New research shows that a weekly contraceptive patch is just as effective as daily oral contraceptive pills in preventing pregnancy.
In the largest trial to date, researchers compared the effectiveness, menstrual cycle control, compliance and safety of two types of contraceptive methods: an oral contraceptive, called Triphasil, and a weekly contraceptive patch, called Ortho Evra. Researchers showed that the patch had some advantages over birth control pills, while maintaining the same contraceptive effectiveness.
“The patch brings ease of use and freedom to a woman trapped in the daily inconvenience of taking the birth control pill without sacrificing contraceptive efficacy,” says co-author, William Koltun, MD, of the Medical Center for Women’s Clinical Research in San Diego, California.
Researchers say oral contraceptives are effective, but poor compliance (such as missed pills) on the part of users increases rates of pregnancy during treatment. By using similar hormones found in the pills (estrogen and progestin), the patch blends the hormones with transdermal delivery–a technology that supplies the hormones for absorption through the skin into the bloodstream.
In the study, researchers looked at 1,417 healthy adult women of childbearing age at 45 clinics in the United States and Canada from October 1997 to June 1999.
Researchers randomly assigned 812 women to receive the patch, which is designed to deliver 20 micrograms of ethinyl estradiol (estrogen) and 150 micrograms of norelgestromin (a chemical that breaks down into a type of the hormone progestin), while 605 women received oral contraceptives for either 6 or 13 menstrual cycles.
Women were told to wear the patch once a week either on the buttocks, upper outer arm, lower abdomen, or upper torso (excluding breasts). The patch was worn for a week at a time and was changed on the same day of each week 3 times a month with the fourth week patch-free.
Women in the patch group could maintain their usual activities but were told not to apply oils, creams or cosmetics on or around the area where the patch was placed. If the patch fell off, it could be immediately reapplied. The fall off rate was less than 2%, according to researchers.
The study shows the difference in the number of pregnancies that occurred among women in the patch group and the birth control pill group was not statistically significant, at 5 and 7 pregnancies respectively. They also note that 3 out of the 7 pregnancies in the pill group were due to failure to comply with the birth control method while only 1 out of the 5 pregnancies in the patch group was for the same reason.
“It is important women have birth control options they are comfortable with and can use accurately,” says Koltun. “The weekly dosing was associated with significantly better compliance than is observed with daily dosing regimens.”
Both treatments were similarly well tolerated, but symptoms such as application site reactions, breast discomfort, and pain or discomfort during or just before a menstrual period were significantly more common in the patch group, according to researchers.
Florence Haseltine, PhD, MD, director, Center for Population Research at the National Institute of Child Health and Human Development in Bethesda, Maryland, says that the findings are very encouraging. They show that women are becoming armed with increasingly more choices of contraceptive methods.
“It’s great to have a new delivery system for contraception,” says Haseltine. “Anything that makes the use of contraception easier and at the same time reversible has tremendous value. The patch will be an important addition to the available contraceptive methods.”
Haseltine says that patches have worked well in postmenopausal hormone replacement therapies. Whether contraceptive patches have long-term efficacy and better compliance in the long-run remains to be determined by future studies. “Post marketing surveillance will continue to be important,” says Haseltine.
Researchers say that better compliance may have played a role in the lower number of pregnancies in the patch group, but cautioned that this finding needs to be confirmed by further research. They also point out that there is an indication in the data that a larger sample size may suggest that better compliance would eventually lead to evidence of increased efficacy.
Currently, the US Food and Drug Administration is reviewing the commercial use of Ortho Evra contraceptive patch, according to researchers.
The study is published in the May 9 issue of The Journal of the American Medical Association (JAMA).
Article By: Hong Mautz, Medical Writer