How to Determine a Due Date From a Date of Conception
- 1). Add 280 days to the first day of your last period, if your cycle averages every 28 days, to find the due date.
- 2). Add 40 weeks to the date you think you conceived, and that is your estimated due date.
- 3). Add 266 days to the date you ovulated, if you have been keeping track of your basal temperature.
- 4). Tell your health care provider the date of the first day of your last period, the average length of your cycle and your estimated date of conception. Allow her to do a pelvic exam and an HCG (Human Chorionic Gonadotropin, also known as "the pregnancy hormone") test, for a more accurate estimation of the gestational stage.
