Originally Posted by clavicula
I have a question.
We are planning on using condoms until ovulation and then nothing (after 3 hight temps). Would you consider this as a safe method? I really do not want to get pregnant in the next 4-5 years.
I assume there is very little chance to ovulate again when temps are nice high, am I right?
Check out this link for more information on using temperature only. It is a very effective method, but do pay attention to things such as illness that can cause an artificial temp rise not related to ovulation. It would be unusual that it would last 3 days unless you were really sick, but that seems to be the most common source of error with the temperature-only method. I would also be careful about looking for a significant temperature rise, not just three "higher" temperatures, but 3 temperatures that are .4F (or .2C) above the highest of the previous 6. If these conditions are met, I would consider temperature only to be a very safe method, over 99% effective.
Condoms, on the other hand, I have more concerns about. The statistics on the efficacy of using condoms to prevent pregnancy are lower than for most other methods of family planning. It is a well-known fact that using barrier methods during the fertile period greatly reduces the effectiveness of FAM (and makes it look a lot more like the statistics for condoms). These are not FAM failures, per se. They are condom failures.
With perfect use, a condom is 98% for a year. When judged over the course of 5 years (.98^5x100), the condom is about 90.93% effective over the course of 5 years with perfect use. That leaves almost a 1 in 10 chance that you would get pregnant using condoms perfectly for 5 years. With typical use, a condom is 85% effective per year in preventing pregnancy. Over the course of 5 years, it is only 44.37% effective. You are more likely to become pregnant than not. A lot of things affect the effectiveness of condoms, so it would be up to you to make a decision on that. Most people get an effectiveness out of condoms that is somewhere between the perfect use and typical use numbers, but in general, condoms are not terribly effective in postponing pregnancy for a long period of time, and the risks should be considered seriously if you have a serious reason to avoid pregnancy for that whole time.
To be fair, the typical-use statistics for NFP (abstinence during the fertile period) are not that great either. It is really something that works well (over 99% for the commonly-used methods) if the rules are followed perfectly, but DTD on the other days is exactly how you try for a baby, so if you don't follow the rules, you are very likely to end up pregnant. Typical use estimates are usually close to 75% effectiveness per year, but with good knowledge of the methods and a healthy amount of sexual self-control, it is very easy to control your ability to get the perfect use effectiveness.
What I can't judge for you is how effective a method you need. With what you are proposing, the effectiveness of the condoms is certainly the limiting factor (You are much more likely to get pregnant due to a condom failure than a temp-only method failure), so it's more about how safe you feel using condoms during your fertile period. It should be noted that no method of birth control besides complete abstinence is 100% effective, and every time we choose to DTD, we are accepting whatever probability there is that we could become pregnant. It's up to each couple to discern what effectiveness they need and take appropriate action.
Edited by JMJ - 9/27/11 at 2:37pm