Panel Urges Steps to Reduce Risk of Inadvertent Harm to Potentially Normal Pregnancies

New recommendations have been issued for the use of ultrasound screening in determining when a first trimester pregnancy is nonviable.

These new diagnostic thresholds, developed by a panel of 15 medical specialists from the fields of radiology, obstetrics-gynecology and emergency medicine, and convened by the Society of Radiologists in Ultrasound (SRU; Reston, VA, USA), were published October 10, 2013, in the New England Journal of Medicine (NEJM). The new steps should help to avoid the possibility of physicians causing inadvertent harm to a potentially normal pregnancy.

“When a doctor tells a woman that her pregnancy has no chance of proceeding, he or she should be absolutely certain of being correct. Our recommendations are based on the latest medical knowledge with input from a variety of medical specialties. We urge providers to familiarize themselves with these recommendations and factor them into their clinical decision-making,” said Peter M. Doubilet, MD, PhD, from Brigham and Women’s Hospital (Boston, MA, USA) and Harvard Medical School (Boston, MA, USA), the report’s lead author.

Among the major points made by the expert panel: (1) Until recently, a pregnancy was identified as nonviable if ultrasound showed an embryo measuring at least 5 mm without a heartbeat. The new standards raise that size to 7 mm; (2) the standard for nonviability based on the size of a gestational sac without an embryo should be raised from 16–25 mm; (3) Lastly, the typically used “discriminatory level” of the pregnancy blood test is not effective for excluding a viable pregnancy.

The panel also warned physicians against taking any action that could injure an intrauterine pregnancy based solely on a single blood test, if the ultrasound findings are inconclusive and the woman is in stable condition.

Kurt T. Barnhart, MD, MSCE, an obstetrician-gynecologist at the Perelman School of Medicine at the University of Pennsylvania (Philadelphia, PA, USA), and a member of the SRU multispecialty panel, added, “With improvement in ultrasound technology, we are able to detect and visualize pregnancies at a very early age. These guidelines represent a consensus that will balance the use of ultrasound and the time needed to ensure that an early pregnancy is not falsely diagnosed as nonviable. There should be no rush to diagnose a miscarriage; more time and more information will improve accuracy and hopefully eliminate misdiagnosis.”

Michael Blaivas, MD, an emergency medicine physician affiliated with the University of South Carolina (Columbia, USA), and one of the panelists, stressed that, “These are critical guidelines and will help all physicians involved in the care of the emergency patient. They represent an up-to-date and accurate scientific compass for navigating the pathway between opposing forces felt by the emergency physician and his/her consultants who are concerned about the potential morbidity and mortality of an untreated ectopic pregnancy in a patient who may be lost to follow-up, but yet must ensure the safety of an unrecognized early normal pregnancy.”

Related Links:
Society of Radiologists in Ultrasound
Brigham and Women’s Hospital