Ultrasound has become an integral component of obstetric care, with the vast majority of patients having at least one ultrasound examination during pregnancy. From the determination of early pregnancy and gestational age to the evaluation of fetal growth and well being, ultrasound is a valuable diagnostic tool for the practicing obstetrician. Recent advances in obstetric ultrasonography have increased its importance in managing pregnancies at risk for aneuploidy, structural anomalies, preterm delivery, and blood flow abnormalities. Compiled of contributions from leading experts across the country, this issue of Obstetrics and Gynecology Clinics of North America demonstrates the expanding role of ultrasound in the field of obstetrics.
In the United States, ultrasound has been incorporated into prenatal screening programs aimed at identifying fetal chromosomal abnormalities. From their important work on the FASTER Trial (First and Second Trimester Evaluation of Risk), a multicenter prospective study comparing first and second trimester methods of screening for fetal aneuploidy, Karlla Brigatti and Dr. Malone provide a thorough review of first trimester screening including the ultrasonographic evaluation of nuchal translucency. The genetic sonogram, comprised of an evaluation of various sonographic markers during the second trimester, has been used to provide an individualized risk assessment for patients. An expert in both Maternal Fetal Medicine and Genetics, Dr. Stewart presents the potential benefits and obvious limitations of ultrasound in the detection of various fetal chromosomal abnormalities.
In addition to decreasing the likelihood of fetal aneuploidy, patients want reassurance that their infants will be born without major structural abnormalities. Dr. Goldberg, who has devoted his career to prenatal diagnosis, provides an excellent overview of the routine screening ultrasound examination and the expected detection rates for fetal anomalies. My chapter on screening for congenital heart disease follows with the conclusion that the evaluation of multiple cardiac views at the time of routine prenatal ultrasound has the highest probability of detecting heart defects prior to birth. In contrast to the prenatal detection of major fetal malformations, there are many ultrasonographic findings that may or may not represent true pathology. Drs. Rochon and Eddleman present a detailed review of the most controversial ultrasound findings and provide a useful evidence-based approach to their management.
Diagnostic and therapeutic interventions are often necessary for patients at risk for aneuploidy or when an ultrasonographic abnormality is identified. Experienced clinicians, Drs. Ralston and Craigo provide a comprehensive review of the various ultrasound-guided procedures that are in use today for fetal diagnosis and therapy.
Although the fetus is often the focus during obstetric ultrasound examination, an evaluation of the cervix may be of importance in some patients. Drs. Doyle and Monga present an excellent discussion on the utility of ultrasound in women with prior second trimester pregnancy loss, previous preterm delivery, and multiple gestation. They provide logical guidelines for the ultrasonographic assessment of cervical length in patients at risk for preterm birth, emphasizing that the transvaginal approach is the optimal way to evaluate the cervix during pregnancy. In addition to an evaluation of cervical length, obstetric ultrasound plays an important role in multiple gestations. Drs. Egan and Borgida provide an extensive review of the use of ultrasound in twins, from diagnosis to delivery, demonstrating its favorable impact on the management of these high-risk pregnancies.
Ultrasound evaluations in the third trimester involve assessments of fetal growth and well-being. An expert in ultrasonography, Dr. Lerner presents an overview of fetal growth and the accuracy of ultrasound to detect abnormalities such as intrauterine growth restriction and macrosomia. In addition to fetal growth, obstetric ultrasound permits an evaluation of the intrauterine environment. In a well-illustrated review, Dr. Marino discusses the use of ultrasound to evaluate the amniotic fluid volume, fetal membranes, umbilical cord, and placenta. This issue of Obstetrics and Gynecology Clinics of North America is concluded with a comprehensive presentation on fetal Doppler velocimetry. All leaders in the field, Drs. Mari, Detti, Cheng, and Bahado-Singh present the major applications of Doppler velocimetry in obstetrics. Although Doppler velocimetry is a relatively new technique, it has become an integral component of fetal testing and represents a significant advance in the field of obstetric ultrasound.
I would like to extend my sincere thanks to the authors who contributed to this issue on “Ultrasound in Obstetrics”. It provides a thorough update on recent advances in the field and it is my hope that the contents will be useful to practitioners providing care to pregnant women.
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