When did you conceive if your ultrasound says are fourteen weeks pregnant?

An ultrasound that indicates a gestational age of 14 weeks means that the embryo was likely conceived 14 weeks prior to the scan. Since pregnancy is typically calculated from the first day of the last menstrual period, which occurs about two weeks before ovulation, you probably conceived your baby approximately 12 weeks before the day of your ultrasound scan. To determine the approximate conception date, count back 12 weeks from the ultrasound date, but keep in mind that ovulation and conception dates can vary.