Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester

Determining the viability of a pregnancy is a major challenge, especially with a pregnancy of unknown location. This review provides specific guidance, including stringent criteria for nonviability, that can reduce the risk of inadvertent harm to a potentially normal pregnancy. Over the past two to three decades, pelvic ultrasonography and measurement of the serum concentration of human chorionic gonadotropin (hCG) (Table 1) have become mainstays in the diagnosis and management of early-pregnancy problems. These tests, which allow earlier detection of pregnancy and more accurate diagnosis of its complications than were previously possible, have revolutionized the management of intrauterine pregnancies and markedly reduced the morbidity and mortality associated with ectopic pregnancy. 1 , 2 Although these tests have indisputable benefits, their misuse and misinterpretation can lead to interventions that inadvertently damage pregnancies that might have had normal outcomes. 3 , 4 There are well-documented instances . . .