Dating your pregnancy know you are dating a control freak
Your due date is based on the first day of your last period; even though you weren't pregnant then.
The goal of prenatal care is to monitor the progress of a pregnancy and to identify potential problems before they become serious for either the mother or the baby.
They went in for their first doctor's appointment and he/she gave them some other date. We start out with the first day of your last menstrual period. Those were some really fun inauguration/commiseration parties.
Then they went for an ultrasound and were told yet another. What if you have no idea when your last period was or your doctor wants to double-check. The ultrasonographer waves his/her magic wand over your belly and takes measurements of the little squiggle in your uterus.
Correspondingly, this calculator will also give the range of days during which sexual intercourse might have led to the conception, based on the factor that sperm can live inside a woman for three to five days.
If you want to find your conception window in order to get pregnant, please use our Conception Calculator.