The most common way to calculate your due date is to start with the first day of your last menstrual period (LMP). Add 7 days, and then count backward 3 months. For example, if your last period started on March 20, you would add 7 days to get March 27. Then subtract 3 months to get a due date of December 27.

Is pregnancy dated from last period?

Your weeks of pregnancy are dated from the first day of your last period. This means that in the first 2 weeks or so, you arent actually pregnant – your body is preparing for ovulation (releasing an egg from one of your ovaries) as usual. Your getting pregnant timeline is: day 1: the first day of your period.

How accurate is dating a pregnancy?

The earlier the ultrasound is done, the more accurate it is at estimating the babys due date. Ultrasounds performed during the first 12 weeks of pregnancy are generally within 3 - 5 days of accuracy. The most accurate time is between 8 and 11 weeks gestation.

When do most second time moms give birth?

The average first mom will give birth at 40 weeks and 5 days. Second-time moms average delivery date is 40 weeks and 3 days—that is an entire week earlier!