Use of the Genetic Sonogram in the United States in 2001 and 2007

Abstract

The genetic sonogram is performed in the second trimester to detect fetal aneuploidy. In a 2001 survey mailed to members of the Society for Maternal-Fetal Medicine in the United States, the responses indicated wide variation among physicians in their Down syndrome screening practices and choice of second-trimester sonographic markers used for the genetic sonogram (Am J Obstet Gynecol 2002;187:1230–1234). In the ensuing years, the reliance of practitioners on second-trimester sonography to screen for aneuploidy has increased. The objective of the present study is to assess changes in sonographic Down syndrome screening since the 2001 survey. A revised and updated version of the 2001 survey questionnaire was mailed in 2007 to Society for Maternal-Fetal Medicine members in the United States. Respondents were asked which sonographic markers they used for risk adjustment as part of the second trimester genetic sonogram. The responses between 2001 and 2007 were compared with descriptive statistics, the [chi square] test for categorical variables, and the Wilcoxon rank sum test for ordinal variables. The response rate was 32% (543 of 1638) in 2001 and 26% (448 of 1756) in 2007. From 2001 to 2007, there was a significant increase in the number of specialists who used the genetic sonogram as a screening tool for Down syndrome (P < 0.0001) and in the use of all sonographic markers (P < 0.0001) except choroid plexus cyst, clinodactyly, sandal gap, and widened pelvic angle, which were used at the same rate. The number of practitioners who would modify a woman’s risk of fetal aneuploidy based on specific likelihood ratios associated with the various sonographic findings almost doubled. The investigators believe that these findings and, especially, The American College of Obstetricians and Gynecologists recommendation for universal screening, predict a further increase in the utilization of second-trimester sonograms and in the demand for their use.