Pregnancy is counted from approximately 2 weeks before you actually conceive a baby. Sounds confusing, doesn’t it?
- The conception date is the day your baby was conceived, generally during the time you ovulate. Most women on a 28 day cycle ovulate 14 days from the first day of their period.
- Gestational age is the approximate conception date with two weeks added on. It’s counted from your LMP (last menstrual period), which is the first day you started bleeding.
Because most women know when their last period was, it’s easier for doctors to calculate from this date. Most women don’t know when they ovulated or the exact date they conceived, so doctors use the period as the date to calculate pregnancy from.
This also means that it’s close to impossible to find out that you’re pregnant before 3-4 weeks gestation. However it’s possible to find out you’re pregnant 1-2 weeks after conception.
Still confused? Here’s a diagram to help you out.