The Billings method.
A type of ovulation method of birth control that monitors changes in the mucus secreted by a woman’s cervix as a guide to when ovulation has taken place; a type of natural family planning employing periodic abstinence during a woman’s fertile period as a means of contraception, or using the same techniques to identify the most likely time for conception, in dealing with infertility.
Fertility awareness-based contraception is a method that relies on identifying specific days during which sexual intercourse is avoided to prevent pregnancy. This technique involves monitoring the changes in the mucus secreted by a woman’s cervix as a means to track fertility and determine fertile and non-fertile periods.