How to calculate your date of conception

By Staff Account on
This is the best explanation I've found about how a pregnancy is dated .... The medical community uses a 28 day cycle to figure out when conception happens. It is assumed that your period is day 1 and conception happens on day 14. This is for the average woman who has regular periods.Having an ultrasound at 18 weeks would mean that the average woman would have conceived 16 weeks ago, not the 18 that most people think. The number of weeks starts from the first day of your last period, so on...Read Full Story