Ultrasound accuracy for dating

20-Nov-2017 05:42

5 ½ weeks gestation means 5 ½ weeks from the first day of the last menstrual period, which is usually about 3 ½ weeks from the date of conception (confusing, isn’t it!

Even average babies can differ by up to 2 to 3 "weeks of growth";.With transvaginal ultrasound, checking for embryonic development known to occur within a certain time frame more accurately dates a pregnancy.