(571) What Are the Ideal Fetal Parameters for the Testicular Migration Process to Be Completed?

Introduction We evaluated a very large series of human fetuses during various stages of fetal development. Objective To evaluate the weight, crown-rump length (CRL), presence of epididymal anomalies, fetal age and assess in which situations the testicles completed the migration process to the scrotum. Methods The position of testes in 240 human fetuses (480 testis) aged between 10 and 35 weeks post-conception (WPC) was analyzed. We performed the measurements of the weight(g), CRL(cm) and fetal foot length (mm) to estimate the fetal age. After dissection testicular position was classified as: a) Abdominal - testis in the abdominal cavity up to the inner ring; b) Inguinal – testis between the inner and the outer ring and c) Scrotal – testis inside the scrotum. Epididymal anatomy was classified as: a) Normal Anatomy: epididymis united to the testis by its head and tail and epididymis totally united to the testis, and b) Epididymal Anomalies: disjunction of epididymal tail; disjunction of epididymal head and total disjunction between testis and epididymis. Means were statistically compared using Fisher and Man-Whitney test (p<0.05). Results The fetuses had weight ranging between 14g and 2860g and CRL ranging between 6.4cm and 34cm. We observed 60 testes (12.5%) situated in scrotum. The 1st testicle located in the scrotum was from a 26WPC fetus with 741g and 23cm of CRL. All fetuses over 31WPC, weighing >1500g and with CRL>30.5cm had both testicles in the scrotum. We observe a 30WPC fetus with disjunction of epididymal tail bilaterally (2 only cases of epididymal anomaly in our sample) with both testicles in abdomen. We observed a strong and significant correlation between age, weight and CRL with the location of the testicle in the scrotum (p<0.001). Conclusions Fetal age, weight and CRL are factors that positively influence the testicular migration towards the scrotum. The presence of epididymal anomalies is as a factor that can interfere in the process of testicular migration. *Supported by Grants from: National Council os Scientific and Technological Development (CNPq-Brazil) and Rio de Janeiro Foundation for Research Support (FAPERJ). Disclosure No