Rapid B-scan (real-time) ultrasonography in the identification and evaluation of twin pregnancies.

Real-time ultrasonography utilizing a hand-held linear array transducer provides a highly accurate method of identifying and evaluating the twin gestation. The rapidity of real-time scanning eliminates interpretational problems caused by fetal movements. Additionally, the versatility of transducer positioning facilitates recognition of appropriate fetal planes for assessment of viability and growth. A prospective study of 595 consecutive pregnancies yielded no misdiagnoses of the number of fetuses present and only one false positive diagnosis of fetal viability.