ShelbyK

From the fertility newsletter, the following is not quite correct:

While it is possible, it is very rare to have regular periods and not be ovulating, so many people with regular periods don’t need to do any specific testing to make sure. From here, estimating the day of ovulation involves some quick math; no matter how long your menstrual cycle is, the second half (after ovulation) is about 14 days. So you can subtract 14 from the day that you anticipate your period to get a rough idea of when ovulation will occur.

What is correct is that no matter the time it takes to ovulate, your second half of the cycle is usually the same number of days from cycle to cycle. However, that number is not necessarily 14 for many people! This is called the luteal phase and short luteal phases can be a big reason why people don’t get pregnant, either because they are incorrectly assuming when their ovulation window happened or because their short luteal phase is not long enough to support an early pregnancy. Working backwards 14 days may be a recipe for missing peak ovulation–kind of disappointing to see it recommended in this newsletter.