Use of diagnostic ultrasound, X-ray examinations, and electronic fetal monitoring in perinatal medicine.

Obstetrical technologies such as electronic fetal monitoring (EFM) and selected diagnostic imaging procedures can be integral components of perinatal care. The Center for Devices and Radiological Health, a unit within the Food and Drug Administration, collaborated with the National Center for Health Statistics in the design and conduct of a National Maternal and Infant Health Survey to collect information from prenatal care providers, hospitals, and mothers on the use of EFM, diagnostic ultrasound, and x-ray examinations during pregnancy, labor, and delivery. A pretest, conducted some months before the survey began, showed that 78.8% of the pregnancies surveyed received a diagnostic ultrasound examination during pregnancy. Approximately 58.3% of the ultrasound-exposed mothers had two or more such examinations. Approximately 10.1% of the ultrasound examinations were performed in the first trimester of pregnancy, 57.0% in the second trimester, and 32.9% in the third trimester. The most common indication for an ultrasound examination was to establish dates or gestational age. Approximately 15.3% of the pregnancies surveyed received an x-ray examination. Approximately 74.6% of the pregnancies were monitored with EFM during labor. External EFM was used alone during 54.9% of the labors and along with internal EFM during 19.7% of the labors. The implications of these pretest findings are discussed, along with a review of the medical literature on the safety and effectiveness of these medical device technologies.