We consider pregnancy to be a normal physiological event in the life of a woman. Structural and hormonal changes that accompany the development and growth of a baby within the uterus occur rapidly. It is helpful if you know about these changes in advance and understand their effects. We are always available to answer your questions and discuss your concerns.
The Due Date
The due date, or estimated time of delivery, is calculated by adding 280–287 days to your last normal menstrual period. Adjustments may be made if you have menstrual cycles longer than 28 days, or if you were taking oral contraceptive pills just before you conceived. Although most lay people consider a pregnancy to last nine months, we have found that dating the pregnancy in terms of months is not precise enough. Instead, we prefer to date the pregnancy in weeks, beginning with the first day of your last normal menstrual period.
Most women will deliver within two weeks before or after the 40th week. Due dates, therefore, are only an approximation, and you should not fix your expectations on a specific day.
Pregnancy is divided into three approximately equal periods called trimesters. The first trimester extends from the first day of the last menstrual period to 12 weeks, the second trimester from 13–27 weeks, and the third trimester from 28 weeks until delivery.