There is no definite estimate of ultrasound scan accuracy, especially when detecting disabilities of a fetus, according to British College of Obstetricians and Gynaecologists member Dr. Joseph S.K. Woo. However, NHS Choices states that internal and endoscopic procedures are more reliable than external ultrasounds.
Ultrasound accuracy significantly depends on the type of ultrasound test performed, the timing of the test, the patient’s condition and the organs tested. According to NHS Choices, an ultrasound can be performed to examine a fetus during pregnancy, detect certain heart conditions or help a surgeon perform a biopsy.
During pregnancy, an ultrasound can be used to assess a delivery date, detect fetal abnormalities or other pregnancy complications and ascertain the sex of the baby. According to the American Pregnancy Association, the results of the ultrasound scans may be inconsistent in the first few weeks of pregnancy. Patients are advised not to rely on ultrasound results when determining paternity, as the dating of conception can be off by at least five to seven days.