It got me wondering: How accurate are due dates, anyway? What percentage of babies are born within a day of their due date? When can I realistically expect this kid to arrive, in other words? But it might surprise you to know that doctors still calculate the expected date of delivery using a method formulated at the start of the 19th century.
Introduction The most important step in the initial evaluation of any pregnant patient is establishing an accurate delivery date due date . Accurate knowledge of the gestational age is important for numerous reasons. For example, certain antenatal screening tests like the quadruple marker screen screening test for fetal aneuploidy and open neural tube defects must be performed with accurate knowledge of the gestational age for an accurate calculation of lab values. Anatomy Pregnancy ultrasound involves an anatomic survey of uterus and adnexa . If ultrasound is performed beyond 18 weeks of gestation, a full fetal anatomic survey is possible .
Pregnancy math can be a little murky. After all, unless you went the IVF-route, your physician has no way of knowing the exact time of conception. Because of this, pregnancy is calculated from the first day of your last menstrual period or LMP.
The thing is, because the date carries such meaning to us, we hang everything on it, and rightly so. Let me tell you why. There are other due date calculation methods that exist that are based on science and research, but these tend not to be used. But even if you were asked — do you actually KNOW your ovulation cycle. Some women know this..