How accurate is this method of screening for calculating gestational age, sex of the baby etc?


The results of an ultrasound scan are only as accurate as the person interpreting the data, the machinery in use, and the purpose of the test. As a screening tool, ultrasounds being non-invasive serve to provide no definitive answer to whether a specific problem exists. It simply provides estimates of the risk level. It is a precursor to diagnostic testing should the concerned party go ahead for one. When it comes to calculating the gestational age of the baby, your doctor will base it on your LMP, hormone levels in your blood and sometimes ultrasound results. However since each pregnancy is different and there is a variation in a woman's cycle the accuracy is not 100% correct. With regards to gender, which can only be determined during the anomaly scan at the earliest can sometimes be dubious owing to the position of the fetus and quality of testing.