Diagnostic Ultrasound and Human Reproduction

Abstract

Diagnostic ultrasound plays a central role in present day of obstetric care. Embryonic development can be established as early as 5 weeks of gestation using transvaginal transducers. Fetal cardic activity can be observed at 6 weeks and fetal movements at 7–8 weeks. At about 10 weeks embryonic development is more or less completed. As from 14–15 weeks of gestation, reasonably detailed information can be obtained about fetal anatomy. At that time, ultrasound studies have clearly demonstrated the presence of an extensive number of dynamic properties in the fetus such as eye movements, swallowing, stomach and urinary bladder filling and emptying, breathing movements. Combined morphologic and dynamic studies of the fetus by ultrasound have lead to the possibility of detecting a large number of structural anomalies as early as 16–17 weeks of gestation. During the second half of pregnancy diagnostic ultrasound has demonstrated its value in the diagnosis of intrauterine growth retardation. Serial measurements on fetal head and upper abdominal circumference will provide information of fetal growth. Growth retardation usually is the result of poor placental perfusion i.e. chronic fetal hypoxia. Sometimes, however, growth retardation is associated with serious structural anomalies. Recently, the introduction of combined real-time and pulsed Doppler equipment has lead to studies on uterine and fetal blood flow. Reproducable changes in uterine artery and arcuate artery flow velocity waveforms as well as various fetal arteries such as umbilical artery, aortic and internal carotid artery have been collected during fetal hypoxia before growth retardation sets in. Diagnostic ultrasound also plays a very important supportive role with respect to the performance of various invasive procedures: chorionic villus sampling, amniocentesis and cordocentesis (umbilical cord punture).