Hormonal birth control was a world changing invention that gave women a lot of new freedom and power. I am so, so glad it was invented. I am less glad that we as a society somehow got stuck on hormones as the ultimate way to prevent babies. Hormones are weird and unpredictable and involved in every part of metabolism. It would be extremely weird if they didn’t have side effects beyond preventing ovulation. And yet the past 40 years of contraceptive history are mostly people refining hormones, rather than inventing something more awesome.
If you want permanent birth control there are some very good options, but temporary and reversible options are pretty scarce. There’s condoms, which are amazing at some things and cause inconveniences way less than those caused by hormones, but more than zero. There vagina based barrier + spermicide methods, which are more convenient but less effective, and regularly putting anti-microbials in the vagina has its own health costs. There’s the copper IUD, which is great at preventing pregnancy but causes horrendous cramping in the vast majority of users.
This is how I got interested in fertility tracking. There are actually only a few days each cycle sex can lead to pregnancy. If it’s more than 5 days before ovulation or 1 day after, you can put all the sperm you want anywhere in the body, and it’s not going to cause a pregnancy. The old way to try and find these days was “counting”, but that doesn’t account for inter- and intra- person variation in cycle length and has a subsequently high failure rate. Luckily (?) there’s a lot of changes in the body that precede and follow ovulation, because ovulation is caused by hormones which are as previously mentioned extremely complicated and involved in a lot of different things. These include temperature, cervical mucous, and saliva electrolyte level (seriously). Tracking all of those still seems like a lot of work, especially since they need to be done first thing on waking up to avoid contaminating the very subtle signals by doing something like moving. But there are some newer options on the market that ovulation with a lot less work, and those seemed worth investigating.
The first of these is to directly measure hormone changes in the urine to detect imminent ovulation. Conveniently, there are hormonal changes that start 5-6 days before actual ovulation. There is no way to do this yourself.
The second option is temperature monitoring. Your temperature dips right before ovulation, and is slightly higher for the ~two weeks after ovulation than the ~two weeks before. For years if not decades, people have tracked this themselves using regular thermometers and paper, and it theoretically works, but you have to do it the second you wake up to dodge the wake up temperature increase, and I personally don’t want to stake contraception on my ability to do fine motor work and record three significant digits exactly when I wake up.
There’s a few other scattered options including monitoring cervical mucus, cervical position, and the shape your saliva dries in (no, seriously). But science x capitalism have provided me with magic computers to track the first two things, and not the any of these, so I’m going to ignore them. Science has patented a toothbrush that will look at your spit for you (no, seriously), but capitalism has yet to put it into production. There are also tools that could be combined with graph paper to turn them from fertility devices to contraception devices, but I’m going to focus on the options that require the least thought possible.
Note that none of these devices are available in the US for the purposes of contraception. You can buy hormone tests to predict ovulation for the purposes of creating babies, but not preventing them. Purely for educational value I’ve looked up the prices on amazon.co.uk, but you should definitely not circumvent the wise and benevolent FDA by ordering from them.
Persona tracks hormones alone. It costs 52 pounds (~$76) for a starter kit and an additional 13 pounds (~$20) per month. It requires peeing on a stick 16 mornings out of your first month and 8 on subsequent months, and you have a good six hour window in which to do it. You feed the sticks into the magic computer machine and it tells you when you are close enough to ovulation that you should abstain from unprotected sex. It reports 94% success rate.
Lady Comp tracks temperature alone. It costs 415 pounds and claims 99.3% rate. That’s higher than a hormonal IUD, which does everything short of going back in time and murdering your partner’s mother to prevent pregnancy, and it seems unlikely that that could be matched by something that could be confused by me using my mattress heating pad.*
Cyclotest is tracks temperature and optionally several other indicators. It costs 150 pounds (~$220 dollars). You need to monitor your temperature for approximately half your cycle. It allows you to enter your cervical mucus viscosity and cervical position to provide additional data but declines to teach you how to do so. Its display is nuanced enough to be used both for contraception and trying to conceive, and if you’re trying to conceive you can supplement the temperature data with hormone tests (~15 pounds/month). It too reports a 94-99% success rate, which makes me think that is either the hard limit of predicting ovulation (maybe failures come from super long lived gametes rather than bad timing), or that Persona and Cyclotest are using the same data to support their different methods.
Of these three, Cyclotest was my favorite before I even looked at the data, because Cyclotest’s website explains both the science of how it works and the mechanics of using their system, whereas Persona organizes it very counterintuitively and Lady Comp just repeats Natural and No Side Effects until your ears bleed. I think I went to amazon to find out what it actually did.
I managed to find the study Lady-Comp must have gotten their 99.3% success rate from. To be fair, that is what it says (full text PDF). And it’s the real world success rate, not the theoretical rate. But it was a retrospective study, meaning they just reached out to people who have previously purchased the device and asked them if they had gotten pregnant. A number of people were unreachable, and not all that were reachable returned the survey. They don’t even report the full number of surveys they sent out, which makes the data completely unusuable. The paper also indicates Lady-Comp requires significantly more data than temperature alone, which would sure be a good thing to indicate on the website.
Persona has a publications section on their webpage, but their contraception page only has articles on awareness, not efficacy, so really this is just one more reason to hate the word awareness. I was unable to find the source of their quoted 94% success rate, but I did find a paper criticizing it.
Cyclotest’s quoted 1-6% failure rate is as good or better than condoms, which surprises me. This paper doesn’t give an absolute failure rate but does say it misidentified fertile periods as non-fertile a vanishingly small percent of the time, which would be more impressive if that were based on hormones or actual conception rates rather than simple calendar checks.. This paper puts the actual failure rate of temperature only methods at up to 3% per month, which is way too high, but not necessarily worse than actual use rates of other methods.
This paper puts the correct use pregnancy rate of an unknown computer aided system at 2%/year and the actual use rate at 12%/year. It’s always hard to parse the real world failure rates. Take condoms. I don’t think someone simply forgoing condoms half the time counts as a strike against condoms. But “correct” use of condoms is actually a lot of work, and at a certain point I feel like condom manufacturers are just trying to pass the buck. Using lube to reduce friction to prevent breakage is a reasonable action you either do or don’t, but no one has ever defined for me exactly how much “vigorous or prolonged thrusting” necessitates changing a condom. And it’s just bad design to have something break exactly when people are least likely to want to check or fix it.
I was really hoping for better than this. Another beautiful theory, killed by an ugly gang of facts
*Which is, side note, the best thing ever and you should totally get one.