Pregnancy Q and A Forum

Ok, here is what I found.

During each menstrual cycle, a woman's ovaries release an egg, or ovum. This process is called ovulation. This typically takes place an average of about 14 days before the start of a woman's monthly period, but the timing varies from month to month even in the same woman (and sometimes does not occur at all). After ovulation the egg moves toward the uterus through the fallopian tubes, where fertilization may take place. An unfertilized egg may live for about 24 hours. If it isn't fertilized, the egg will be shed during the next menstrual period, along with the lining of the uterus.

A woman is most likely to become pregnant if sexual intercourse occurs just before or just after ovulation. Sperm can survive for several days -- typically two or three -- inside a woman's body. Under ideal circumstances, however, they may remain viable for up to five days. So if sperm are deposited early -- such as during a woman's period -- they can hang around a few days, waiting until conditions are right for conception.

In addition to the survival skills of sperm, a recent study in the british medical journal highlights another reason why couples sometimes conceive during the woman's period. Research results indicate that the "fertile window," or time during the month when pregnancy can occur, is highly unpredictable for most women.

During the three-month study, researchers collected data about the hormone and ovulation patterns of 221 healthy women who were trying to get pregnant. They found that, overall, an estimated 2% of women were in their fertile window by the fourth day of their cycle, and 17% by the seventh day. (day one of the menstrual cycle is the day a woman starts her period.) on every day between days 6 and 21, there was at least a 10% probability, on average, that a woman could become pregnant. In addition, women who reported regular periods had up to a 6% probability of being fertile on the day that menstruation was expected to start. Ovulation was even harder to predict in women with irregular periods, according to the study. The researchers concluded that timing intercourse to avoid (or achieve) pregnancy is quite difficult and cannot be done with precision.

Article cited from msn health!

Pregenancy