Normal Fetal Development and the Time of Origin of Some Structural Abnormalities

Abstract

One branch of contemporary Fetal Medicine is ‘to search out and see’: that is, to use ultrasound scanning to visualise the embryo and fetus in utero to determine whether it is developing normally, both temporally and structurally. Structural anomalies, or congenital malformations, can affect all systems of the body and many of them originate in the very early stages of embryonic development during organogenesis. However, a few do originate later in pregnancy when a normally formed structure is altered in some way. Ultrasound scanning is becoming increasingly refined and excellent views of the fetus can now be obtained. By using vaginal probes, good views may now be obtained at very early stages of pregnancy, right back to the embryo. However, no imaging technique yet provides the equivalent of a photograph of the embryo or fetus.