The Food and Drug Administration recently approved Natural Cycles, an app that uses a woman’s body temperature to tell her when she is ‘fertile’ or ‘not,’ as a form of birth control.
But doctors are not fully on board with this contraceptive.
Women have been planning around their periods and ovulation for thousands of years.
During ovulation, a woman’s body temperature goes up several degrees, before falling again once her most fertile days are past.
So many other confounding factors also influence body temperature, but the app, of course, is not sensitive to all of these, and may be more vulnerable to error than other forms of birth control.
The FDA approved Natural Cycles, an app that uses a woman’s body temperature to track when she is ovulating, but experts say that the system is imperfect and gives women false security
Natural Cycles is an app sold for $79.99 per annual subscription (and includes a basal thermometer) and intended to help women establish when they can have unprotected sex without getting pregnant and when they are most fertile.
The app’s interface is sleek and modern in predominantly white and fuchsia but the concept is anything but.
Natural family planning is just the practice of tracking a woman’s menstrual cycle as a way to determine when she is most likely to get pregnant.
On average, a menstrual cycle lasts 28 days, with most women bleeding as they shed the uterine lining on day one, then ovulating on or around day 14.
Ovulation, when an egg is released into the Fallopian tube and moves toward the uterus, is when a woman is most fertile, and the egg can survive for about a day in the Fallopian tubes.
During ovulation, and for anywhere between 48 and 72 hours on either side, a woman’s temperature goes up by abut one degree.
This is what Natural Cycles tracks.
The app requires women to use a basal thermometer – which is more sensitive than a regular thermometers – to take her temperature at the exact time every day.
When it registers a higher temperature, it will give a red ‘fertile’ signal, reminding women that they may get pregnant if they try to have sex before their temperature goes back down.
Typically after 48 hours, the egg is no longer viable and the uterine lining is shed.
This is ‘really just a different way to talk about family planning,’ explains Dr Haywood Brown, president of the American College of Obstetricians and Gynecologists (ACOG).
‘The Catholics have practiced it for years and years and years,’ he says, eluding to the propensity for family planning to fail them, among others.
But first, a woman has to get used to the normal trajectory of her menstrual cycle, unregulated by hormones.
Natural Cycles advises taking two to three cycles (abut a month each) to wait . Dr Brown says that sounds about right.
‘Women have different types of cycles. the whole fertile part of the cycle is after ovulation, but some omen have a cycle every 26 days, and that means ovulation is probably on day 12, or 14 days and then they don’t have another period,’ says Dr Brown.
‘If you have deviations from that fertile period, that’s why.’
Plus, ovulation is not the only factor in a woman’s world that could cause her temperature to go up a single degree.
‘Obviously, this is not very precise because a lot of things can affect your temperature, like getting a cold, or if you’re a runner,’ Dr brown says.
That’s not to mention the wide margin for human error.
In theory, taking your temperature at exactly the same time every day should help to establish an accurate baseline.
The app notifies users on days that they they may be close to ovulating and, therefore, fertile, that they should use protection, but these days can be thrown off easily by temperature shifts
In practice, life happens. Some mornings you might wake up fighting off a cold, others you might just be running late, getting your heart pumping and your temperature up, still others you might have to step outside into the chilly morning air.
‘That’s why purists in natural family planning also use cervical mucus,’ Dr Brown says.
The mucus in a woman’s vagina changes consistency during ovulation and a woman can learn to notice for herself and use this measure along with temperature to more accurately track her fertility.
But Natural Cycles includes no measure or tracking of cervical mucus.
Even if it did, ‘this is not like traditional birth controls that have a 99.9 percent chance they’re not going to fail,’ Dr Brown says.
‘These things are not perfect.’
This is, in part, because sex takes two.
‘Sperm lives about 72 hours, so you would really need to abstain not for 48 hours, but for more like a week,’ Dr Brown explains.
Natural Cycles’s website says women end up with an average of 10 ‘red’ days during each cycle and should be ‘comfortable’ using protection with their partners during these higher risk days.
‘The longer you abstain, the more your partner is involved, the more likely this is to work,’ says Dr Brown.
‘But you’re dealing with two people with sex, not just one.’
Natural Cycles claims that it is 93 percent effective at preventing pregnancy, a number that Dr Brown says he is a bit dubious of.
Before the FDA approved Natural Cycles, a Swedish hospital reported that 37 women had come there for abortions after using Natural Cycles.
‘Women using this have to be aware of other pregnancy prevention methods like the morning after pill, if they’re not opposed to that,’ says Dr Brown.
Despite its vulnerabilities for failures Natural Cycles falls into a sort of regulatory loop hole.
‘It’s very safe for the FDA to approve it, because it’s not a drug,’ which would have to be proven not to have any dangerous side effects, Dr Brown explains.
‘Anybody can develop an app like this, because it’s not really birth control, it’s a way to monitor natural family planning, so I don’t know why you would seek approval for it,’ he adds.
‘I wouldn’t say it’s irresponsible for the FDA to approve it, but devices like this can lure women into a false sense of security.’