I was recently discussing birth control with friends of mine, about the various costs and advantages of each system. We discussed condoms, emphasizing their relative safety in use (for preventing both pregnancy and disease). We also discussed “the pill,” which the Germans call “the anti-baby pill,” as an effective anti-pregnancy method that unfortunately carries often unspoken ecological and potential health risks (it halves the size of the ovaries but has thus far not been associated significantly with any health risks).

Our discussion extended from effectiveness, health impacts, relative protection, and environmental consequences to the difficulty of acquisition and logistics in creation and distribution. Not entirely satisfied with all of the most common options (“the pill”, condom, completely avoiding sex, and the day-after pill), we then turned to the internet. More specifically: we turned to pubmed (which I can only recommend if you are trying to find evidence, instead of pseudoscience).

We looked into using biological indicators to track fertility, since our body relays information using hormones and that this would have some connection to a woman’s body in a measurable way.

We stumbled onto a piece of gold: a 2007 study by Frank-Herrmann et al (full text here) about a method that reduced the odds of pregnancy down to 0.4% per year without anyone buying anything or incurring any environmental costs. This translated to a 99.6% effectiveness, per year, for reducing pregnancy.

The trick is for the woman to first chart out her fertility cycle, and then use daily readings to determine her position in this cycle. From a total of 900 women, with 226 participating for 3 years and keeping a  daily log book of when they had sex and where they were in the cycle, there was only a total of 15 pregnancies. If we pretend that only the 226 were in the study, and then attribute all pregnancies to them, we still end up with a 94% effectiveness over a 3 year period: pretty damn good.


From Frank-Herrmann et al, 2007

So, how do you actually monitor your fertility cycle, and is this method a smart one? Well, monitoring your fertility cycle requires you to keep track of your basal body temperature, your menstrual cycle, and your cervical secretions (so, your down-under fluid production).

You should seriously inform yourself, and keep track of these cycles and your position in them, before actually trying this as a serious method of birth control. If you decide to use it, you will also need to exercise self-control during periods of higher fertility (unless you are trying to have a baby). You can track the parameters outside of a cycle to know, on a specific day, whether you are fertile or not.

If you really don’t want a kid then it is still advisable to use a more permanent means like an IUD or the pill. There are also women who have very irregular cycles, and they may want to rely on other methods for a greater measure of control. Well informed adults are most certainly capable of determining what is the best option for them.

The next question: is it a smart method? Well, if you are in a stable monogamous relationship and have good self-control and the capacity to monitor your physical signs: yes, it is then a smart method that is pretty highly effective and carries no negative health or environmental risks. If you are the kind of person that sleeps with multiple partners at irregular intervals: condom use is probably the smartest bet for both preventing pregnancy or catching anything nasty.