New natural method of family planning over 95% effective in preventing pregnancy, study finds

The Standard Days Method (TM), a new natural method of family planning, is more than 95% effective at preventing pregnancy, according to an international study conducted by Georgetown University Medical Center’s Institute for Reproductive Health. Results of the study are published in the current issue of Contraception, the journal of the Association of Reproductive Health Professionals.

Based on sophisticated computer modeling of reproductive physiology data, the Standard Days Method identifies the 12-day “fertile window” of a woman’s menstrual cycle. These 12 days take into account the life span of the woman’s egg (about 24 hours) and the viable life of sperm (about 5 days) as well as the variation in the actual timing of ovulation from one cycle to the next. The study found the efficacy of the Standard Days Method to be comparable to or better than a number of other widely used methods of family planning, including the diaphragm and condom.

The two-year clinical trial evaluated the effectiveness of the Standard Days Method of family planning for 478 women in Bolivia, Peru and the Philippines. The women were of childbearing age with menstrual cycles between 26 and 32 days long. The study followed the women over 13 cycles.

“Millions of women worldwide use no form of family planning whatsoever, even though they do not want to become pregnant. And millions more rely on periodic abstinence as their primary form of family planning, but do not have a clear understanding of which days in their cycle they should avoid unprotected intercourse,” said Victoria Jennings, PhD, Georgetown professor of obstetrics and gynecology and principal investigator of the study. “Clearly there is a need for a simpler, easier method of natural family planning–and that is where the Standard Days Method can really fill a void.”

To help women keep track of which days to avoid unprotected intercourse, the Institute for Reproductive Health developed CycleBeads (TM), a string of 32 color-coded beads with each bead representing a day of the menstrual cycle. Beginning with the red bead, which represents the first day of her menstrual period, the woman moves a small rubber ring one bead each day. The brown beads are the days when pregnancy is very unlikely, and the glow-in-the dark white beads (beads 8-19) represent her fertile days. The 478 women who participated in the clinical trial relied on CycleBeads to track their cycles.

The method works best for women whose cycles are usually between 26 and 32 days long. Women use the CycleBeads and the Standard Days Method the same way every month.

“In our research, CycleBeads were found to be an easy way for women to use the Standard Days Method. They are an effective tool for women who want to use a reliable, inexpensive, non-invasive, non-hormonal method of family planning,” said Dr. Jennings.

The Standards Days Method differs from the rhythm method in that the rhythm method requires that the woman collect detailed information about the last six menstrual cycles and perform monthly calculations to figure out which days in the current cycle she is most likely to get pregnant. The Standard Days Method requires no such calculations. No reliable, scientific effectiveness trial of the rhythm method has been reported.

According to the 1998 edition of Contraceptive Technology, 85% of women who use no method of family planning will get pregnant in one year. The percent of women who will become pregnant during the first year of perfect use of a “user-controlled” method is as follows:

Cervical cap, 9 – 26%
Spermicides, 6%
Diaphragm, 6%
Female condom, 5%
Male condom, 3%
Birth control pills, 0.1 – 0.5%
Standard Days Method, 5% (2002 Georgetown study)

Several thousand women in 14 countries currently use the Standard Days Method and CycleBeads. Plans to manufacture and distribute CycleBeads in numerous countries, including the United States, are currently underway. More information about the Standard Days Method and CycleBeads can be found at www.irh.org.

Co-authors of the new Standard Days Method study published in Contraception are Marcos Arevalo, MD, MPH and Irit Sinai, PhD, both assistant professors of obstetrics and gynecology at Georgetown University Medical Center. The study was funded by the U.S. Agency for International Development.

Georgetown University Medical Center includes the School of Medicine, School of Nursing and Health Studies, the Lombardi Cancer Center and a $120 million biomedical research enterprise. The Institute for Reproductive Health (www.irh.org) conducts research, advances scientific information, and provides policy support in natural family planning and fertility awareness.