Second and Third Trimestric Scan Versus Second Trimestric Scan Alone in Detection of Congenital Fetal Anomalies

The third-trimester ultrasound scan ,traditionally performed at 32-34weeks, can assess fetal viability , presentation, anatomy , growth, amniotic fluid volume, placental location and fetoplacental Doppler.

There are multiple other indications that can trigger a third-trimester scan, including antepartum bleeding , reduced fetal movements, preterm rupture of the membranes and suspected abnormalities of fetal growth based on physical examination. In addition, ultrasound may be used to guide other procedures in the third trimester, such as external cephalic version. However, as yet, there is no convincing evidence that routine universal third-trimester ultrasound examination in a low-risk population improves either perinatal or maternal outcome especially in low socioeconomic countries with limited resources