PRENATAL DETECTION OF CONGENITAL RENAL DISEASE

Urogenital anomalies in human male fetuses

BACKGROUND

There are few studies in the literature performed in human fetuses evaluating the incidence of genitourinary anomalies.

AIMS

Analyze the incidence of congenital urogenital malformations in human male fetuses. STUDY DESIGNS AND SUBJECTS: We analyzed 166 human male fetuses well preserved. The gestational age was determined in weeks post conception (WPC) according to the foot length criterion and ranged from 10 to 35 WPC. The fetuses were dissected with the aid of a stereoscopic lens with 2.5x magnification. We performed abdominal and pelvic incisions to expose the urogenital organs. We studied the incidence of renal, ureteral, vesicle, urethral, testicular, epididymal, vas deferens, prostate and penile anomalies.

RESULTS

Of the 166 fetuses, 7 (4.2%) presented some kind of anomaly of the urogenital system. Renal anomalies were found in two fetuses (1.2%). Unilateral renal agenesis was found in a 25 WPC fetus. Horseshoe kidney was found in a 20 WPC fetus. In a 23 WPC fetus (0.6%) the two testes were absent. Epididymal disjunction anomalies were found in four fetuses (2.4%).

CONCLUSIONS

The urogenital anomalies in human male fetuses are rare and have an incidence around 4%.

Predictive value of amniotic fluid cystatin C levels for the early identification of fetuses with obstructive uropathies

OBJECTIVE

To compare the diagnostic accuracy of cystatin C with that of creatinine in discriminating renal function in fetuses without ultrasononographic evidence of renal malformations from those with obstructive uropathies.

DESIGN

Prospective, observational cohort study.

SETTING

Prenatal morphologic and functional evaluation of fetal obstructive uropathies throughout pregnancy.

POPULATION

A total of 96 healthy pregnant women at different stages of pregnancy, without any pregnancy-related maternal disease. Eighty-one pregnant women without clinical and ultrasonographic evidence of any fetal anomaly, confirmed at birth, were defined as controls; 15 pregnant women with various fetal obstructive uropathies, evidenced by repeated ultrasound examinations and confirmed at birth, were defined as cases.

METHODS

Creatinine was measured by a kinetic Jaffe picric acid method and cystatin C by a nephelometric immunoassay. Variables were analysed by applying conventional statistical tests; the non-parametric receiver operating curves (ROC) analysis was used to evaluate the diagnostic efficiencies of the biochemical markers.

MAIN OUTCOME MEASURES

Incidence of confirmed, diagnosed, neonatal obstructive uropathy by measuring baseline levels of cystatin C and creatinine in amniotic fluid.

RESULTS

Baseline levels of cystatin C in amniotic fluid were significantly higher (P = 0.0015) among cases than in controls with comparable gestational age; no significant difference was found for creatinine levels (P = n.s.). The maximum diagnostic accuracy of serum cystatin C in discriminating controls from fetal uropathies was 96%, while that of creatinine was 62%.

CONCLUSION

Cystatin C may be considered a sensitivebiochemical marker for the early identification of fetuses with obstructive uropathies.

Urinary tract anomalies and dysfunctional voiding: a spectrum dictated by the influence of amniotic pressure upon fetal urodynamics

The etiologic basis of urinary tract anomalies and dysfunctional voiding largely remain unknown. However, the travel of urine from renal pelvis into the amniotic cavity under the pressures exerted by amniotic fluid satisfactorily explains the etiologic basis. Amniotic pressure is affected by the changes in maternal intraabdominal pressure. The intraabdominal pressure of the fetus is also dictated by the amniotic pressure. Amniotic pressure compresses the urethra throughout the length, and may increase both bladder leak point pressure and urethral resistance. Furthermore, the urine is propelled against amniotic pressure. These factors closely simulate outflow obstruction. Since the pressure within the bladder with minimal urine content reflects the intraabdominal pressure, intravesical pressure is also elevated during fetal life. Additionally, elevated intravesical pressures impair ureteral drainage. The compressive effect exerted by fetal intraabdominal pressure upon ureters, further elevate the pressure within the renal pelvis. While forwarding the urine against these pressures may result in anomalies of the urinary tract, the increased work load of the detrusor may act as a state of injury that forms the basis of dysfunctional voiding.