How accurate are dating scans at 7 weeks
Therefore, we will tell you how to calculate pregnancy weeks and months . Your pregnancy due date is calculated by adding 40 weeks (i.e., 280 days) to the first day of your last menstrual period (LMP).
This is done with an assumption that you have a 28-day menstrual cycle.
As you near the due date, you may have to start counting your pregnancy by days as – 39 weeks one day, 39 weeks two days, and so on (6).Also known as dating scan, it will provide the number of weeks remaining for your due date (7).If the scan does not give the correct results, your doctor may ask you to wait for some more time.The due date calculation works ideally if your periods are regular, i.e., follow a 28-day cycle.If your periods are irregular or you do not remember your last period, you should wait for your first ultrasound pregnancy scan.