Over the last few months I’ve talked to several
women who have told me that they “count their days” as a natural form
of birth control. By this I assume they mean they are practicing some
form of the calendar or rhythm method. These methods attempt to use
past cycles to predict when a woman will ovulate and by abstaining from
intercourse during this time each month. I would like to make
something clear: although “counting days” can sound a lot like Natural
Family Planning (NFP), it is actually very different and a lot less
effective. Here is why:
1- The calendar method assumes a “normal" cycle with
ovulation occuring the same day each month, typically day 14. In
reality, even with a very regular cycle, a woman’s ovulation day can be
days earlier or later than this, and can fluctuate depending on diet,
stress and other factors – making the calendar/rhythm method even less
accurate. And if a woman does not have a “normal” 28-day cycle, proper
NFP methods become even more important.
2- The calendar/rhythm method leaves out several important factors. For instance, some women think that they can have intercourse up until the time they’ve ovulated. This seems reasonable because, how can pregnancy occur if there’s no egg yet for the sperm to fertilize? But sperm can live up to 5 days after intercourse, making the few days leading up to ovulation part of the most fertile phase – even though the egg is completely absent at the time of intercourse. Add to this the fact that the woman's egg can live for up to 24 hours after ovulation and you have a window that’s even harder to predict using the calendar or rhythm method. These factors are crucial in determining a woman's actual fertile time.
3- By miscalculating a woman’s fertile time, the calendar/rhythm method may actually lead couples to have intercourse during the days that pregnancy is most likely to occur.
4- It is possible that the calendar method may lead couples to abstain for longer than necessary since it is based on the woman's past cycles, not her current fertility signs.
Overall, the calendar method just isn't very effective. It’s an outdated guessing game that leaves couples at the mercy of a calendar. Although the calendar method is often equated with Natural Family Planning, NFP is actually very different. Instead of using past cycles to predict fertility, NFP uses a woman’s current biological indicators to determine when she is actually fertile. The difference between the two methods is evident when we examine their effectiveness rates-- NFP is 98% effective while the calendar method is only about 80%-90% effective.
For more on the effectiveness of NFP see my past blogs or read more here.
2- The calendar/rhythm method leaves out several important factors. For instance, some women think that they can have intercourse up until the time they’ve ovulated. This seems reasonable because, how can pregnancy occur if there’s no egg yet for the sperm to fertilize? But sperm can live up to 5 days after intercourse, making the few days leading up to ovulation part of the most fertile phase – even though the egg is completely absent at the time of intercourse. Add to this the fact that the woman's egg can live for up to 24 hours after ovulation and you have a window that’s even harder to predict using the calendar or rhythm method. These factors are crucial in determining a woman's actual fertile time.
3- By miscalculating a woman’s fertile time, the calendar/rhythm method may actually lead couples to have intercourse during the days that pregnancy is most likely to occur.
4- It is possible that the calendar method may lead couples to abstain for longer than necessary since it is based on the woman's past cycles, not her current fertility signs.
Overall, the calendar method just isn't very effective. It’s an outdated guessing game that leaves couples at the mercy of a calendar. Although the calendar method is often equated with Natural Family Planning, NFP is actually very different. Instead of using past cycles to predict fertility, NFP uses a woman’s current biological indicators to determine when she is actually fertile. The difference between the two methods is evident when we examine their effectiveness rates-- NFP is 98% effective while the calendar method is only about 80%-90% effective.
For more on the effectiveness of NFP see my past blogs or read more here.
