Can You Get Pregnant on Unfertile Days?

Every woman has times of fertility and infertility in her cycle. Though a woman only ovulates for one day, she is considered fertile for about a week prior to ovulation. Understanding ovulation, the symptoms and its time frame, can help you pinpoint your fertile days.

Function

• The average woman experiences a 28-day fertility cycle, however, variations are common. The first day of menstruation signifies day one. After menstruation, estrogen causes the cervical lining to build up and the luteinizing hormone (LH) stimulates the ovarian follicle to release an egg. Soon after ovulation, the follicle that released the egg becomes yellow and is called the corpus luteum. The corpus luteum creates a surge of progesterone that remains elevated for the rest of the cycle.

Time Frame

• During a 28-day cycle, a woman menstruates during the first week. During this time, she is not fertile. The next week, though, is her most fertile time. The egg is released toward the end of this week. The last two weeks of the cycle are also highly unfertile. After ovulation, progesterone suppresses subsequent ovulation. An egg will live for about 12 to 24 hours, so after the egg dies, a women enters another unfertile period, the luteal phase. Some women experience delayed ovulation---ovulation that occurs after day 20---so checking for fertility symptoms is important for women who have longer cycles.

Unfertile Days

• During menstruation, ovulation is still several days away; however, the lighter the flow gets and the further away from day one a woman is, the more likely it is that a longer-living sperm may be around when the egg is released. Unexpected pregnancies can happen when intercourse has occurred in the days immediately following menstruation before symptoms of fertility are present. In addition, after ovulation has occurred and the unfertilized egg dies, the surge of progesterone released from the corpus luteum inhibits a subsequent ovulation, so pregnancy is very unlikely at this time.

Fertile Days

• A few days after menstruation, a woman will be at her most fertile for several days. During this time, intercourse could lead to pregnancy. Though ovulation is only one day, a woman is considered fertile for several days prior, as cervical mucus helps sperm in their migration. Also, as stated earlier, sperm may live up to seven days. Even if intercourse doesn't happen on the day of ovulation, some sperm may be present to fertilize the newly released egg. Once the egg is released and the corpus luteum starts to secrete progesterone, the egg only will live for 12 to 24 hours. Once her egg dies, she will not be fertile again until the next cycle.

Considerations

• Consistently checking your basal body temperature and cervical mucus, over time, can help pinpoint your most fertile days. Immediately after ovulation, progesterone triggered by the corpus luteum causes your resting body temperature, also called your basal body temperature, to rise approximately 0.4 degrees. A woman's most fertile time is the seven days leading up to this temperature spike. Also, cervical mucus, both internal and external, will be thick and stretchy to help with sperm mobility. Check mucus at least once a day to determine if you may be fertile.