The most accurate measurement for dating is the crown-rump length of the fetus, which can be done between 7 and 13 weeks of gestation.After 13 weeks gestation, the fetal age may be estimated by the diameter of the head and the length of the femur.
The nuchal translucency is a measurement of an area of fluid behind the baby’s neck.It can determine if a baby is present, the position of the fetus and if there is a multiple pregnancy.It can also help to diagnose abnormalities or problems, help determine the age of the pregnancy and subsequent due date as well as showing the position of the placenta in relation to the birth canal.Anomaly scan and fetal sex determination (20 weeks scan) This scan is a routine scan in the UK which takes place at around 20 weeks.This is one of the best times to have an ultrasound done as most infants are the same size at this stage of development.Dating a pregnancy accurately at the earliest possible time is important.
In a normal pregnancy it does not matter what the dates are, but if anything should go wrong it becomes very important as to what treatments may be prescribed.
You will lie on your back on an examination couch and the transducer moved back and forth across your stomach in order to gain the best possible image of the fetus.
Ultrasound imaging in pregnancy is widely used to evaluate the baby.
A thorough examination of the fetus’s brain, heart, spine, kidneys, organs and limbs will be carried out and the placenta checked for its position.
Measurements of the fetus will also be taken to ensure it is growing normally.
For instance, if your period starts on the 5th April, then your estimated due date for delivery is the 12th January.