A foetal age determination test is often carried out to estimate the gestational age, and in turn, the foetal age and this is often carried out by way of an ultrasound, during the first trimester or about 8 weeks into the pregnancy. If you are worried about your pregnancy, and feel the need to know about the due date as well as the health of the foetus, you can consult your doctor and get a foetal age determination test done at the earliest. There are several methods by which your obstetrician can check on your pregnancy from ultrasound exam, bimanual exam to serum HCG tests. However, one of the most commonly used methods to accurately predict the age of the foetus happens to be an ultrasound exam