The position of the testis during the fetal period. An additional parameter to estimate fetal weight.

PURPOSE To establish a correlation between testicular position and fetal weight, in order to provide an additional prenatal parameter for fetal weight estimation. MATERIALS AND METHODS We studied 288 testes from 144 human fetuses. The fetuses were assessed as regards weight, total length, crown-rump length and foot length. Fetal age was calculated according to the foot length criteria. The position of the testis was classified as abdominal, inguinal or scrotal. RESULTS One hundred and ninety seven testes (68.4%) were abdominal, 43 (14.9%) were inguinal and 48 (16.6%) were scrotal. In the fetuses weighing up to 500 grams, 147 testes (93.5%) were abdominal and 5 testes (6.5%) were inguinal. In fetuses weighing between 501 and 1000 grams, 54 testes (68.6%) were abdominal, 28 testes (32.5%) were inguinal and 4 testes (4.6%) were scrotal. In fetuses weighing between 1001 and 1500 grams, 4 testes (13.3%) were abdominal, 3 (10%) were inguinal and 23 (76.6%) were scrotal. All fetuses weighing more than 1500 grams presented the testes with a migration to the scrotum (10 fetuses - 20 testes). CONCLUSIONS To our knowledge, this is the first study correlating the testicular position to the fetal weight during testicular migration in human fetuses. Identification of the testes during the prenatal period could be a useful alternative parameter for estimating fetal weight.