Doubilet PM, Benson CB, Bourne T, Blaivas M
Over the past two to three decades, pelvic ultrasonography and measurement of the serum concentration of human chorionic gonadotropin (hCG) 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.
Doubilet PM, Benson CB, Bourne T, Blaivas M. Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester. N Engl J Med 2013; 369:1443-1451