How do doctors calculate your due date?

Answer by  LauraLS (195)

Most doctors calculate a due date by adding 40 weeks to the first day of your last period. The actual day of conception might be later, so most babies are born within 2 weeks of the due date.

Answer by  snessia (991)

Initially doctors calculate your due date as 40 weeks from the first day of your last period. Based on baby's size and development during pregnancy, this date may be adjusted.

Answer by  amswplusone (652)

If you have a regular menstrual cycle, you can calculate your due date based on when you'd be ovulating (which happens about two weeks after your last period). External measurements, like measuring your belly, are usually consistent for a given developmental age. Lastly, measurements of the actual baby from an ultrasound are accurate ways to predict your delivery date.

Answer by  Ali41 (1593)

Your due date is forty weeks from the date your last period in a 28-day cycle. First, they may just ask you for your last period and assume you have a 28 day cycle. Second, if you have an early ultrasound (6-10 weeks), they can measure the fetus's progress to determine a date.