Urethral and bladder development during the 2nd gestational trimester applied to the urinary continence mechanism: translational study in human female fetuses with neural tube defects

Introduction and hypothesis We hypothesized that anencephaly impacts female lower urinary tract development during the human fetal period. The aim of the present study is to compare the biometric parameters of the bladder and urethra in female human fetuses with and without neural tube defects. Methods We studied 34 female fetuses (22 normal and 12 anencephalic), aged 12 to 22 weeks post-conception (WPC). After pelvic dissection and individualization of the urinary tract structures, we evaluated the bladder and urethra length and width using Image J software. Means were statistically compared using the Wilcoxon-Mann-Whitney test, and linear regression was performed. Results We identified statistical significance between the groups regarding bladder length [normal: 6.58–19.98 mm (mean = 12.13 ± 3.21 SD) vs. anencephalic: 4.59–15.27 mm (mean = 8.79 ± 3.31 SD, p = 0.0048] and urethral length [normal: 2.22–7.04 mm (mean = 4.24 ± 1.45 SD) vs. anencephalic: 0.81–6.36 mm (mean = 3.25 ± 1.71 SD, p = 0.05]. We did not observe significant differences in bladder and urethra width between the two groups. The linear regression analysis indicated that the bladder length in anencephalic fetuses increased faster than in normal fetuses. Conclusions We observed significant differences in the development of the bladder and urethra in fetuses with anencephaly during the fetal period studied, proving that anencephaly can affect the development of the female fetal lower urinary tract.