Mucus becomes clear, slippery, and stretchy, signaling ovulation is near. You are most likely to become pregnant during this period. (Sperm survive for two to five days after intercourse, which is why sex now can lead to pregnancy even though ovulation is still several days away.)
Estrogen rises dramatically, which boosts LH. LH stimulates the synthesis of progesterone, which causes FSH to rise. Within 12 hours of ovulation, body temperature rises between 4/10 and 8/10 of a degree and, if pregnancy does not occur, remains high until the next menstrual period.
Estrogen falls sharply and LH surges, which causes the ovary to release the egg—ovulation. The egg lives for about 12 to 24 hours.
Day 15 (may extend to day 24)
The empty egg follicle—the corpus luteum—secretes increasing amounts of estrogen and progesterone to help prepare the uterus for a possible pregnancy. FSH and LH levels begin to drop.
When your body temperature has stayed high for three days in a row, generally your fertile period is over.
Cervical mucus becomes cloudy.
Days 21 to 22
Progesterone level peaks.
The corpus luteum breaks apart. If the egg was not fertilized, progesterone begins to drop and cervical mucus is tacky. (If fertilization occurred, your progesterone level remains high.)
Mucus is absent or dry.
Estrogen level decreases and progesterone production rapidly drops. Mucus is thick. If you’re not pregnant, your period will begin tomorrow.