Conception date can be date of ovulation, egg retrieval, or insemination.
The pregnancy due date is estimated by adding 280 days (9 months and 7 days) to the first day of the last menstrual period (LMP).
When the date of conception is known precisely, such as with in vitro fertilization, the estimated pregnancy due date is calculated by adding 266 days to the date of conception.
Please remember that your due date is only an estimate. Every pregnancy is unique and your baby will come when it's ready. Be sure to talk to your health care provider about your due date.