Prenatal diagnosis by ultrasound.

Prenatal diagnosis is defined as the determination of the nature of a disease in the fetus. Although only 3% to 5% of infants are born with a birth defect, prenatal diagnosis is an expanding field in health care practice. Prenatal diagnosis involves the disciplines of obstetric ultrasound, laboratory study for chromosome analysis/biochemical evaluation, and genetic counseling. To provide prenatal diagnosis, caregivers need state-of-the-art equipment, up-to-date procedures, and well-defined protocols. A critical tool used to provide prenatal diagnostic information is ultrasound, which is a widely accepted method for fetal diagnosis and assessment. This article describes the background of ultrasound, outlines fetal abnormalities that can be diagnosed with ultrasound, and discusses the relationship between diagnostic ultrasound and genetic counseling.