Penile Length can be Estimated by the Foot-Length? Study in Human Fetuses with Neural Tube Defects

BACKGROUND: There are no reports comparing penile length with foot-length between normal and anencephalic fetuses. AIM: To compare the penile length with foot-length in fetuses with anencephaly and without anomalies. Materiais and methods: We studied 32 fetuses without anomalies, aged 11-22 weeks post-conception (WPC) and 13 anencephalic fetuses, aged 13-19 WPC. We evaluated penile free portion length and width, penile root length and width and total penile length with a digital caliper and the aid of computer programs (Image Pro and Image J). The Shapiro-Wilk test was employed to ascertain the normality of the data and to compare quantitative data between normal vs. anencephalic fetuses. Simple linear correlations were calculated for penile measurements according to foot-length. OUTCOMES: This is a morphometric study of human fetuses using a standardized technique to measure the penis in human fetuses. RESULTS: Total penile length varied from 4.69 to 29.77mm (mean =15.67) in normal fetuses and from 7.49 to 18.46mm (mean=11.48) in anencephalic fetuses without significant differences. The linear regression analysis indicated that the total penile length has a strong and significant correlation with the foot length in the control group (r2=0.8505, p<0.001) and a moderate correlation of total penile length and foot length in the anencephalic group (r2=0.6813; p=0.0032) and the penile body and root width increased significantly and positively with fetal foot length in normal and anencephalic fetuses. CLINICAL IMPLICATIONS: This study may suggest a correlation between foot size and penis size in human fetuses during the 2nd gestational trimester of development. Strengths & Limitations: Sample size was small; however, anencephalic fetuses are rare, so observations of a small sample are still relevant. CONCLUSIONS: Penile length increased significantly and positively when correlated with foot length during the 2nd trimester of gestational development. We can suggest that foot size can be considered an indicator of penis size in human fetuses.