Sonographic measurement of corpus spongiosum in male fetuses

Abstract

We established measurements of the length of fetal corpus spongiosum and a correlation between the former and the penile length. These references can be useful when fetal genital anomalies are suspected.

Sonographic measure techniques of fetal penile length

“…Although we cannot make a physical examination like pediatricians, obstetric ultrasound allows the detailed evaluation of the male genitalia, including the size of the penis, the size of the scrotum, and the size and location of the testicles [ 22 ]. It is possible to measure variables of the penis such as its length, width, and diameter, as well as that of the comprising structures such as the corpus cavernosum, corpus spongiosum, and glans [ 23 ].…”

“…Other authors have reported measurement strategies using alternative features. The length of the fetal penis has been measured from the tip of the glans to the pubic symphysis [ 12 ], to the proximal edge of the corpus cavernosum [ 29 ], and to the proximal edge of the corpus spongiosum [ 23 ]. Although correlation between OPL and these measures of “total penile length” was high and authors provided instructions for simplifying these measurements, no later work has repeated these methods.…”

“…In case of fetal erection, it is a phenomenon that has not been studied in detail. It is known that fetal penises can have erections due to factors such as changes in blood flow or contraction of the pelvic muscles [ 30 ], and that it is a relatively frequent finding in the third trimester to observe an average of 1 to 3 erections hourly [ 23 ] No work has specified whether the measurements in their references tables were made with relaxed or erect fetal penises, and the scope of bias that this introduces is unknown.…”

“…The series by Perlitz et al [ 29 ], Vuillard et al [ 23 ], and the second report by Nemec et al [ 12 ] are not based on the OPL measure, but rather use alternative techniques. At first glance the results of Nemec et al [ 12 ] come closest to reference measurements, since both are based on the measurement from the tip of the penis to the edge of the pubic symphysis.…”

Prenatal management of disorders of Sex development

“…Later in pregnancy, assignment is based on direct visualisation of the genital anatomy, including the scrotum and midline raphe of the penis in males, and the three lines, representing the labial lines, and uterus in female fetuses. There are charts of fetal penile length available but their utility has yet to be proven and different publications give slightly different normal ranges [5,6]. Three-dimensional ultrasound is of limited use for sonographic sex determination in routine practice, but it may be useful in defining malformations of the external genitalia.…”