The taking of the basal temperature, the one that has the body under normal circumstances, can help to know which days are most fertile, although on its own it is not infallible, and should be combined with the observation of cervical mucus to have greater certainty. The reason is that body temperature is slightly lower from the moment menstruation ends to ovulation and then rises slightly, around 0.2-0.5 degrees. When this elevation is maintained for three days in a row, it is the unequivocal sign that the fertile period has ended. The temperature drops again immediately before or after menstruation.

Gynecologists always recommend that couples seeking pregnancy have sex between days 7 and 20 of the menstrual cycle, although most couples focus on days 11 to 14. Keep in mind that, even if the menstrual cycle is very regular, ovulation rarely occurs regularly mathematically, as it can be anticipated or delayed and even double ovulation occurs on successive days. Measuring the basal temperature and cervical mucus observation will help pinpoint when fertile days begin and end.

It is also necessary to consider that the half-life of sperm is 4-5 days, while that of the egg ranges between 12 and 24 hours, although it is easier to develop fertilization of the same between 4 and 6 hours after it has been released.

How to measure basal temperature

As has already been said, basal temperature will rise after ovulation, so before using it as a reference for fertile days, it will be necessary to take temperature and annotation the value obtained for at least one month to know what the variations are throughout the cycle Menstrual. To do this, the following steps must be followed:

  • Use a digital thermometer. He’s the most accurate.
  • Do it every day and always at the same time, as the body temperature varies throughout the day. It’s best to do it every morning when you wake up.
  • Always perform temperature measurement in the same place: mouth, anus or vagina. It is not recommended to do so in the armpit because it can be more inaccurate.

basal temperature

  • If you’ve slept less than four hours.
  • If you’ve had alcohol.
  • If he’s out at night.
  • If she’s sick.
  • If you’re stressed.

This will check that the temperature rises between 0.2 and 0.5 degrees the day after ovulation and will remain so until or after menstruation. To find out what the fertile days are you will have to observe the cervical mucus, inserting the index finger into the vagina to obtain a sample. The mucus will have the appearance of egg white, with a clear (almost transparent) coloration, a thick consistency and, if pressed slightly with the thumb, when separating it, fine threads that do not break form.