The estimated date of delivery EDD , also known as expected date of confinement  , and estimated due date or simply due date , is a term describing the estimated delivery date for a pregnant woman. Confinement is a traditional term referring to the period of pregnancy when an upper-class, noble, or royal woman would withdraw from society in medieval and tudor times be confined to their rooms with midwives, ladies-in-waiting and female family members only to attend them. Except in threatened pregnancies for example, in pre-eclampsia , "lying-in" or bedrest is no longer a part of antenatal care. According to American Congress of Obstetricians and Gynecologists , the main methods to calculate gestational age are: . Childbirth on average occurs at a gestational age of days 40 weeks , which is therefore often used as a standard estimation for individual pregnancies. There is in any case considerable variation among individual pregnancies.
Whats more accurate? LMP Due date or ultrasound?
Whats more accurate? LMP Due date or ultrasound? - June Babies | Forums | What to Expect
A dating scan is an ultrasound examination which is performed in order to establish the gestational age of the pregnancy. Most dating scans are done with a trans-abdominal transducer and a fullish bladder. If the pregnancy is very early the gestation sac and fetus will not be big enough to see, so the transvaginal approach will give better pictures. Dating scans are usually recommended if there is doubt about the validity of the last menstrual period. By 6 to 7 weeks gestation the fetus is clearly seen on trans-vaginal ultrasound and the heart beat can be seen at this early stage 90 to beats per minute under 6 to 7 weeks, then to beats per minute as the baby matures. Ultrasounds performed during the first 12 weeks of pregnancy are generally within 3 - 5 days of accuracy.
You can calculate your due date by subtracting three months from the first day of your last menstrual period LMP and then add a week. Use our pregnancy calculator. A pregnancy is based on being days long, which is 40 weeks more like 10 months not 9! When we give you a due date we consider 37 to 42 weeks to be full-term, so even if your baby is born two weeks before your due date it is not considered premature. Because few women know the exact day they ovulated or conceived, an ultrasound done in the first trimester of pregnancy has been shown to the be the most accurate way to date a pregnancy.
This baby was a huge surprise and I was breastfeeding when I got pregnant. But since then I have been measuring weeks ahead and when she did my fundal today she was surprised that I was measuring so far ahead again. My first came over two weeks early when I actually knew my conception date, and consistently measured small.