The fetal thyroid: normal and abnormal sonographic measurements

Abstract

The thyroid of 31 fetuses at low risk for perinatal thyroid disease were evaluated sonographically. The transverse width and circumference of the fetal thyroid was measured prospectively to provide normative values for each gestational age. In addition, the thyroid of 23 fetuses at risk for thyroid disease were examined sonographically and compared to the control group. At birth, 18 of the neonates had no evidence of thyroid dysfunction, whereas 5 newborns had goiters and abnormal thyroid function. The fetal thyroid measurements for these 5 neonates were above the upper limit of the 95% confidence interval compared to the control group. The other 18 fetuses in the group at risk for thyroid disease but without evidence of thyroid dysfunction at birth had fetal thyroid measurement within the normal range.