High-frequency transvaginal sonographic examination for the potential malformation assessment of the 9-week to 14-week fetus.

A study was undertaken to evaluate the ability of the high-frequency transvaginal scanning method to consistently image first- and early second-trimester fetal structures, such as body contours, long bones, fingers, face, palate, feet, toes, and the four-chamber view. Ninety-seven low-risk pregnancies were scanned from 9 weeks to 14 menstrual weeks inclusive. Accurate dating was ascertained. The results showed that consistent detection of the respective structures was achieved at the following menstrual ages: sagittal contours at 9 weeks to 10 weeks, long bones at 10 weeks to 11 weeks, fingers at 12 weeks, face and palate at 12 weeks, feet and toes at 13 weeks, and the four-chamber view at 14 weeks. The organs and structures examined could be detected at 9 weeks to 14 weeks inclusive. An increasing number of structure were detected consistently with the increasing menstrual age. The study supports the possibility of searching for specific malformations at or after the menstrual ages mentioned, or performing a more comprehensive malformation evaluation after 13 weeks.