Usually, a missed period is the first sign that a woman can attribute to the suspicion she may be pregnant. Imagine the shock she may get when she finds out that some women still experience their periods, even after they are pregnant. Often these periods are lighter and shorter than a normal period. In fact, because a woman's first trimester is affected by many of the same symptoms as premenstrual cycles, she may not even notice anything strange aside from frequent bouts of nausea.
Typically, a woman who does not suspect pregnancy yet still experiences her period may not find out she's pregnant until she is nearly two months into her first trimester. Obviously, this can affect the development of the child if she has a lifestyle that includes heavy drinking or smoking. Women who do this should tell their health care providers immediately about the potential for development of fetal alcohol syndrome.
Women who experience light bleeding may also have it done so while the blastocyst is implanting on her uterine wall. This overlaps with the time line of a woman whose menstrual cycle is on a 28- to 31-day cycle.
Women who are pregnant and experience bleeding during their pregnancy should contact their health care providers immediately as it may be an indication of a miscarriage or other pregnancy complication.