When is my baby due? The unborn baby spends around 38 weeks in the uterus (womb). The average length of pregnancy is calculated as 40 weeks because it is counted from the first day of the woman’s last period, not the date of conception, which generally occurs two weeks later.
Since some women are unsure of the date of their last menstruation, a pregnancy is considered full-term if birth is between 37 to 42 weeks of the estimated due date.
Remember this due date is an estimate. Most babies don't arrive exactly on their due date. The majority will arrive either three weeks before or two weeks after their due date.
For more information please refer to the BHC fact sheet on
Baby due date.
