The Standard Days method is a kind of calendar method. It’s simpler than other FAMs, but you can only use it if your cycles are a certain length and regular.
The Standard Days Method is based on reproductive physiology. A woman’s fertile window (the days in the menstrual cycle when she 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 a woman’s reproductive tract for up to five days, and the ovum can be fertilized for up to 24 hours following ovulation. Therefore, a woman’s fertile window is approximately 6 days long per cycle.
However, during any given cycle a woman’s potential fertile days can vary due to the fact that the exact timing of ovulation can vary from one cycle to the next. Most ovulations occur around the mid-point of the menstrual cycle (+/- 3 days).
Researchers at the Institute for Reproductive Health identified the potential fertile window in a woman’s menstrual cycle during any given cycle 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 days 8 through 19 of the cycle provided maximum protection from pregnancy while minimizing the number of days to avoid unprotected intercourse.
Women with menstrual cycles between 26 and 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.
How do I use the Standard Days method?
You can only use the Standard Days method if:
- Your menstrual cycle is really regular (your periods always come at the same time)
- Your cycle is never shorter than 26 days
- Your cycle is never longer than 32 days
- You’re okay with either not having vaginal sex or using birth control from day 8 through day 19 of each cycle.
To use the Standard Days method, you simply don’t have vaginal sex or use another method of birth control on days 8-19 of your cycle.
Most people using the Standard Days method by using an app or have a special string of beads, called CycleBeads, that helps them keep track of their cycles. CycleBeads have 33 coloured beads and a black rubber ring that moves from bead to bead.
Note: Breastfeeding, a recent pregnancy, and hormonal birth control (including the morning-after pill) can mess with your menstrual cycle and affect how well the standard day’s method will work.