Real-time ultrasonographic evaluation of normal fetal adrenal glands.

Using real-time ultrasonography, the normal fetal adrenal glands can be consistently imaged after 30 weeks of gestational life. It was found that the normal fetal adrenals had specific size, shape, and echogenicity and could be consistently separated from the adjacent kidneys. The long axis of the adrenal gland had a range of 14 to 22 mm, compared with a range of renal lengths of 27 to 42 mm, with a ratio of the long axes of fetal adrenal to fetal kidney of .48 to .66. These figures compare favorably with dimensions of the adrenals and kidneys found in newborn autopsies. Since certain in utero abnormalities change the size and shape of normal fetal adrenal glands, these data should serve as a reference to evaluate adrenal disturbances. In addition, it would be expected that failure to image either the kidney or adrenal gland after 30 weeks would strongly imply abnormality in that gland.