Summary of Key Points Continued advancement of ultrasound technology including increase in frequency and choice of focal position have improved visualization of fetal anatomy and therefore have also increased the required anatomic knowledge of these structures for those performing and…
Summary of Key Points Early diagnosis and determination of chorionicity in the first trimester are critical for the optimal management of multiple gestations. Dichorionic twins may be either monozygotic or dizygotic, whereas essentially all monochorionic twins are monozygotic. In addition…
Summary of Key Points In the first trimester, gestational age should be assigned to the pregnancy based on sonographic findings or mean sac diameter prior to the visualization of the embryo and by embryonic or fetal crown-rump length (CRL) thereafter.…
Summary of Key Points Evaluation of fetal anatomy, including a detailed fetal cardiac examination, is possible in the late first trimester. Many anatomic abnormalities can be detected in the first trimester, giving families time to make important decisions regarding pregnancy…
Summary of Key Points The progression of transvaginal sonographic findings in normal early first trimester pregnancies follows a highly predictable pattern, with a gestational age variability of approximately ±0.5 week: gestational sac at 5.0 weeks, yolk sac at 5.5 weeks,…
Summary of Key Points Major fetal malformations are highly associated with fetal chromosomal abnormalities, particularly central nervous system anomalies, facial abnormalities, cystic hygroma, diaphragmatic hernia, cardiac defects, gastrointestinal abnormalities, genitourinary anomalies, nonimmune hydrops fetalis (NIHF), and abnormalities involving the extremities.…
Summary of Key Points In the population, 2% to 3% of newborns have a congenital malformation or genetic disease identified at birth. Despite advances in genetics, the cause of more than half of human congenital abnormalities remains unknown. Chromosomal abnormalities…
Summary of Key Points Recent years have seen dramatic advances in ultrasound technology, including improved spatial and contrast resolution, routine use of three-dimensional (3D) and four-dimensional (4D) imaging, volumetric scanning, expanded indications for color and spectral Doppler, new and improved…