4 ms·

Because people of reasonable intelligence also realize that ovulation has occasional hiccups in timing, that on rare occasions sperm can live a surprisingly lon

by mcherm 10y ago

Because people of reasonable intelligence also realize that ovulation has occasional hiccups in timing, that on rare occasions sperm can live a surprisingly long time, and that as a result"fertility awareness" (on its own) is a less reliable means of contraception than most other options.

y7 10y ago
I'd really like to learn the proper numbers on this. What are the precise risks of a timing hiccup or second ovulation during a menstrual cycle? Also, how does regularity of one person's period affect these risks? How accurate are the indicators for ovulation most methods use (body temp, cervical mucus, etc.)?
- LyndsySimon 10y ago
  Well... it depends. If you only rely on this method for a few days each month immediately after the end of menses, the chances of it failing are MUCH lower than if you rely on it for a week prior and a week after menses. That said, wiki claims[1] that the latter approach is >95% effective in perfect use, and 88% effective in typical use. Compare this to withdrawal[2], which wiki claims is 96%/78% effective respectively. [1]: https://en.wikipedia.org/wiki/Calendar-based_contraceptive_methods#Standard_Days_Method https://en.wikipedia.org/wiki/Calendar-based_contraceptive_m... [2]: https://en.wikipedia.org/wiki/Coitus_interruptus https://en.wikipedia.org/wiki/Coitus_interruptus
  - MustardTiger 10y ago
    You linked to the rhythm method, not fertility awareness. Fertility awareness means actually measuring the physiological changes resulting from the hormonal changes that precede ovulation (temperature, saliva, cervical mucous). This is much more reliable than guessing based on the date, which is obviously going to fail relatively often as ovulation isn't reliably regular even in the most "regular" cycles.
LyndsySimon 10y ago
With a typical amount of deviation in the time of ovulation, the rhythm method still allows 1-2 weeks per month with very low risk of pregnancy. Combined with withdrawal when the risk is unacceptably high, it can be acceptably effective. > "fertility awareness" (on its own) is a less reliable means of contraception than most other options You're absolutely correct, of course - but some people's situations don't require such a high level of reliability. For instance, my wife and I used the rhythm method for four years after marriage without incident, until we decided to try for our first child. During that time an unexpected pregnancy would not have been unwelcome. We weren't where we wanted to be financially, but we would have been fine. Our ballpark assumption of a 10% chance of conception per year was an acceptable level of risk to outweigh the negatives of a barrier method or hormone-based option.
MustardTiger 10y ago
You are thinking of the rhythm method, that has nothing to do with fertility awareness, which is finding out for sure when ovulation is occurring, not guessing based on dates. Fertility awareness is more reliable than condoms, but nobody goes around acting like condoms are not a reasonable option: https://en.wikipedia.org/wiki/Comparison_of_birth_control_methods https://en.wikipedia.org/wiki/Comparison_of_birth_control_me...

by mcherm 10y ago

y7 10y ago

I'd really like to learn the proper numbers on this. What are the precise risks of a timing hiccup or second ovulation during a menstrual cycle? Also, how does regularity of one person's period affect these risks? How accurate are the indicators for ovulation most methods use (body temp, cervical mucus, etc.)?

LyndsySimon 10y ago
Well... it depends. If you only rely on this method for a few days each month immediately after the end of menses, the chances of it failing are MUCH lower than if you rely on it for a week prior and a week after menses. That said, wiki claims[1] that the latter approach is >95% effective in perfect use, and 88% effective in typical use. Compare this to withdrawal[2], which wiki claims is 96%/78% effective respectively. [1]: https://en.wikipedia.org/wiki/Calendar-based_contraceptive_methods#Standard_Days_Method https://en.wikipedia.org/wiki/Calendar-based_contraceptive_m... [2]: https://en.wikipedia.org/wiki/Coitus_interruptus https://en.wikipedia.org/wiki/Coitus_interruptus
- MustardTiger 10y ago
  You linked to the rhythm method, not fertility awareness. Fertility awareness means actually measuring the physiological changes resulting from the hormonal changes that precede ovulation (temperature, saliva, cervical mucous). This is much more reliable than guessing based on the date, which is obviously going to fail relatively often as ovulation isn't reliably regular even in the most "regular" cycles.

LyndsySimon 10y ago

With a typical amount of deviation in the time of ovulation, the rhythm method still allows 1-2 weeks per month with very low risk of pregnancy. Combined with withdrawal when the risk is unacceptably high, it can be acceptably effective. > "fertility awareness" (on its own) is a less reliable means of contraception than most other options You're absolutely correct, of course - but some people's situations don't require such a high level of reliability. For instance, my wife and I used the rhythm method for four years after marriage without incident, until we decided to try for our first child. During that time an unexpected pregnancy would not have been unwelcome. We weren't where we wanted to be financially, but we would have been fine. Our ballpark assumption of a 10% chance of conception per year was an acceptable level of risk to outweigh the negatives of a barrier method or hormone-based option.

MustardTiger 10y ago

You are thinking of the rhythm method, that has nothing to do with fertility awareness, which is finding out for sure when ovulation is occurring, not guessing based on dates. Fertility awareness is more reliable than condoms, but nobody goes around acting like condoms are not a reasonable option: https://en.wikipedia.org/wiki/Comparison_of_birth_control_methods https://en.wikipedia.org/wiki/Comparison_of_birth_control_me...