Sex without contraceptives? There’s an app for that.

Would you trust an app and thermometer to have sex without rubbers, pills or coitus interruptus as a way to prevent unintended pregnancies? According to Swedish startup Natural Cycles, there’s a 100% natural and 99.9% proven method to prevent pregnancies – once you use their app to get the timing right.

The science behind Natural Cycles follows the principle of fertility awareness (FA), a field of studies that observes the regularities and chemical states of the female menstrual cycles. If you’ve ever been around a couple having difficulty making a baby, you’d know that there are only a few days per menstrual cycle when a woman can actually get pregnant. A woman’s “fertile window” ends with ovulation, and sperm can only live in a woman’s body for two to five days. For most women, this leaves only around six days per menstrual cycle where unprotected sex is able to get pregnant. For any other day, you’re “good to go”, so to speak.

An issue, however, is that due to the changing nature of the human body and irregular menstrual cycles, it’s hard to accurately predict when a woman will be ovulating based on historic data. But there are signs that a woman is preparing to ovulate, which includes basal body temperature, cervical mucus, and cervical position.

Natural Cycles harnesses the research of predicting ovulation based on basal body temperature and combined a thermometer with their own algorithm and app to accurately predict when it’s safe to have sex without protection, and when it’s not.

In practice

It’s not as simple as taking your temperature whenever you remember to do so. Natural Cycle users must measure their temperatures each morning after making sure they have had enough sleep (optimally eight hours). It’s important to make the measurement right after waking up because the body reaches basal temperature during sleep, and this temperature will start increasing the moment we open our eyes in the morning.

Too short periods of sleep, large amounts of alcohol, and illnesses cause irregularities in the body temperatures, which is why if this is the case, it’s better not to submit temperature data to prevent corrupted information from displaying false results. You could, however, submit the temperature and warn the algorithm about known irregularity factors, so that the data consistency remains without the data submission affecting the accurate fertility predictions.

There are several details on top of temperature a user can/should submit into the algorithm: menstruation, intercource, personal notes and Ovulation (LH) Test results. The Ovulation test means testing the LH hormone with ovulation test strips the days before expected ovulation (which is recommended as it will better isolate the fertile window and yield more green days).

Future of birth control?

Natural Cycles does offer an interesting alternative to hormone-based birth control since it has no side effects, regardless of your genetic inheritance or medical condition tendencies. In extreme cases, the negative effects of pills can even cause blood clots that have been known to result in fatalities!

The Natural Cycle method claims to be 99.9% effective if used correctly, which means doing everything strictly by the book. In comparison, studies have shown that typical use of condoms have a roughly 14% failure rate. Nonetheless, condoms are so far the only thing that guarantees high protection from STD’s, so lustful singles with several partners should keep that in mind.

Other significant benefits in FE is that it’s relatively cheap, and if you’re still troubled by the abstinence problem, there’s always the option of using other protection methods during the fertile periods. In terms of price, a simple comparison seems to be in place: Natural Cycles offers a one year package, which includes the thermometer, for $59.90. In comparison, imagine buying a years worth of birth control pills, your occasional morning after pill and a bagful of condoms. Prices may vary, but it’ll be hard to get a years supply for less than $60.

In addition to price, if you do decide to put the buns in the oven, the Natural Cycles method will easily let you know when’s best time to do it, so there’s that as well.

We were fairly skeptical when first finding out about the company (and joked about their return policy) but after doing some research Natural Cycles looks like a reliable form of birth control for couples unless STD’s worry you. The company has office presence in Switzerland and Sweden, run by the three main players behind the startup, Dr. Elina Berglund and Dr. Raoul Scherwitzl, CTO and CEO of Natural Cycles respectively, as well as Prof. Dr. Göran Berglund who works as the medical adviser of Natural Cycles.

As quite an impressive side note, according to Natural Cycles, CTO Elina Berglund seems to have been among the physicists who discovered the Higgs boson at CERN. Call me naive, but I think I could trust my birth control in an application build by her.

Woman texting while her partner is sleeping next to her photo by shutterstock