What is basal body temperature?
Basal body temperature is slightly different than the general temperature a person takes, and can technically be taken in both men and women. But for conception and specifically ovulation, a basal body temperature refers to the temperature when a woman is fully at rest.
How does basal body temperature impact ovulation?
Experts have found that ovulation can cause a rise in a woman’s basal body temperature. Specifically, a woman’s temperature can begin to rise 2-3 days after the ovaries have released an egg. Knowing when a woman’s temperature is increasing can help a couple identify the best days to have sex and increase the chances of successfully conceiving. If a couple is solely focused on ovulation, a slight temporary increase of 0.4 degrees for a sustained 48-hour period is usually an indicator that a woman is ovulating. But a prolonged rise in temperature for 18 or more days can also serve as an early sign that a woman is pregnant.
How to track basal body temperature
As compared to other ovulation tracking methods, relying on the basal body temperature method requires consistency and diligence. For the best results, a woman should take a reading in the morning, ideally at the same time every day. Experts recommend that a woman get at least five hours of sleep before tracking the temperature. The type of basal body thermometer isn’t as important as using the same method every time, such as orally, rectally, or vaginally. However, keep in mind that many experts suggest that a woman may need to record basal body temperature readings for several months before determining a clear pattern to predict ovulation.
Basal body temperature and family planning
While tracking basal body temperature can give a woman or couple a general window where ovulation may occur, the method isn’t considered reliable if a couple is trying to avoid getting pregnant. Relying on this form of birth control is known as the fertility awareness method (FAM). Even if a woman can see a clear pattern in temperature changes, experts recommend relying on an additional birth control method or completely avoiding sex during the suggested ovulation window.
Reasons for temperature changes
While basal body temperature is considered relatively accurate for fertility monitoring, some scenarios and inconsistent test times and methods can impact temperature readings. Smoking, drinking, being sick, or even stress can change a woman’s temperature. So a woman could potentially assume ovulation is or isn’t occurring because of a faulty reading.
Ovulation tracking methods
Recording basal body temperature is one of several options that a woman can use to track fertility. However, being inconsistent with timing and tracking methods, along with environmental stressors can artificially alter readings. If a woman is unable to adhere to the rigorous requirements for basal body temperature tracking, an alternative method such as test strips that check for changes in hormone levels can be a more reliable option to pinpoint an ovulation window. To learn more about ovulation tracking, speak with a healthcare provider.