Types of Natural Family Planning: Fertility Awareness Methods: 2: another method to predict ovulation using the changes in cervical mucus that occur naturally with ovulation Before ovulation each month, the cervical mucus is thick and does not stretch when pulled between the thumb and finger. Just before ovulation, mucus secretion increases. With ovulation ( the peak day), cervical mucus becomes copious, thin, watery, and transparent. It feels slippery and stretches at least 1 inch before the strand breaks All the days on which cervical mucus is copious, and for at least 1 day afterward, are considered to be fertile days, or days on which the woman should abstain from coitus to avoid conception. In addition, breast tenderness and an anterior tilt to the cervix occur.