U. S. Sen. Hillary Rodham Clinton, D-NY, and, former President Bill Clinton, blow out the candles on a cake at Hillary Rodham Clinton's 59th birthday party at Tavern on the Green in New York, Thursday, Oct. 26, 2006.
The unborn baby spends around 38 weeks in the uterus, but the average length of pregnancy, or gestation, is counted at 40 weeks. Pregnancy is counted from the first day of the womanâs last period, not the date of conception which generally occurs two weeks later.
So when we say a womanâs estimated gestational age is six weeksâ LMP, we mean she conceived about four weeks ago, around the time of ovulation. The expected duration of a pregnancy is 40 weeks from the first day of LMP (four weeks more than the traditional nine months by which many count). Medical professionals consider delivery premature when it occurs before 36 weeks, and extremely premature when it occurs before 28 weeksâ LMP.