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CycleBeads® and the CycleBeads smartphone apps are based on a fertility awareness-based method called the Standard Days Method®. This method was developed by the Institute for Reproductive Health at Georgetown University to fulfill the need for an effective, easy-to-use, natural birth control option. It is designed for cycles between 26 and 32 days long.


The Scientific Basis for the Standard Days Method


The Standard Days Method is based on established research of reproductive physiology and statistical analysis.. The fertile window (the days in the menstrual cycle when a person can get pregnant) begins approximately five days prior to ovulation and lasts up to 24 hours after ovulation. This is because sperm remain viable in the female reproductive tract for up to five days, and the ovum can be fertilized for up to 24 hours following ovulation. Therefore, the fertile window is approximately 6 days long per cycle.

However, during any given cycle, the potential fertile days can vary due to the fact that the exact timing of ovulation can vary from one cycle to the next. Ovulation usually occurs around the mid-point of the menstrual cycle (+/- 3 days).

Researchers at the Institute for Reproductive Health identified this extended, potential fertile window by using a computer simulation that took into account the probability of pregnancy, probability of ovulation occurring on different cycle days, and variability in cycle length from woman to woman and from cycle to cycle. Their analysis found that avoiding unprotected sex on cycle days 8 through 19 provided maximum protection from pregnancy while minimizing the number of days needed to avoid unprotected intercourse.

People with menstrual cycles 26 to 32 days long can use CycleBeads and the Standard Days Method to prevent pregnancy by avoiding unprotected intercourse during the 12 fertile days identified by the method, cycle days 8 through 19.

Effectiveness of the Standard Days Method

In efficacy studies conducted in several countries, researchers found the Standard Days Method to be more than 95% effective in preventing pregnancy when used correctly and 88% effective with typical use. This means that when the family planning method is used correctly, fewer than 5 of every 100 persons who track their cycles consistently and do not have unprotected intercourse on cycle days 8 through 19 will become pregnant during the first year of using the Standard Days Method.  In typical use, when the method is sometimes used incorrectly or inconsistently, 12 in 100 people will become pregnant.

To read the original research article, click here: Efficacy of a New Method of Family Planning: The Standard Days Method. Based on this research, CycleBeads compares favorably to other contraceptive options both in Correct Use effectiveness and Typical Use effectiveness.


Implications for Using this Natural Family Planning Option 


If a person does not want to get pregnant, they should use a back-up method of birth control, such as condoms, or not have sex on cycle days 8 through 19. On the other hand, if a person does want to get pregnant, these are the days when pregnancy is most likely. CycleBeads and the CycleBeads smartphone apps based on the Standard Days Method help enable correct and effective use of this method. See  CycleBeads and CycleBeads Smartphone App.

1. Arevalo M. et al., Contraception, 2002;65;333-338.
2. Wilcox AJ, Weinberg CR, Baird DD. Post-ovulatory ageing of the human oocyte and embryo failure. Human Reproduction, 1998;13(2):394-397.

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