- Fetal hydronephrosis is seen in approximately 0.1% to 5% of all pregnancies on prenatal
ultrasonography. - Fetal hydronephrosis is most often transient or clinically insignificant.
Measurement of the maximum renal pelvic anteroposterior diameter in the transverse plane is the
most accepted method to define fetal hydronephrosis. - In general, the likelihood of having a significant renal anomaly correlates with the severity of
hydronephrosis. - Because fetuses with hydronephrosis are at increased risk for Down syndrome and congenital
anomalies of the kidney and urinary tract, a comprehensive prenatal evaluation is required for these
conditions. - Fetuses with second-trimester unilateral hydronephrosis should undergo repeat testing in the third
trimester at 32 to 34 weeks to assess progression and select those who will benefit most from postnatal
testing. - MANAGEMENT
Management is based on the presence of extrarenal and other renal anomalies, amount of
amniotic fluid volume, gestational age, severity of hydronephrosis, and whether the FH is unilateral
versus bilateral. - Because mild hydronephrosis serves as a weak marker for Down syndrome, assessment of the fetal karyotype should be offered if additional fetal anomalies are detected, in women of advanced maternal age, and in women with abnormal maternal serum screening tests for Down syndrome.
- Fetuses with unilateral mild hydronephrosis should have a follow-up ultrasonographic scan at
32 to 34 weeks. Those with resolution have a low risk of clinically significant disease, whereas RPD
greater than 7 to 8 mm at this gestational age is an indication for postnatal evaluation.
Moderately severe FH, solitary kidney or bilaterality, progression on serial examinations, presence
of oligohydramnios, renal dysplastic changes such as hyperechogenicity or renal cysts, thickened
bladder wall, ureteromegaly, presence of urinoma, or urinary ascite necessitate close follow-up every
2 to 3 weeks to assess progression and amniotic fluid volumes. - Early delivery has been suggested for fetuses with severe oligohydramnios and documented
lung maturity and may be indicated to reduce the risk of other adverse outcomes from oligohydramnios
such as umbilical cord compression. Antenatal bladder drainage by a vesicoamniotic shunt for LUTO may increase the amount of amniotic fluid, thus potentially improving lung development and survival rate; however, further studies are needed to determine whether intervention improves survival.28 There remains a high rate of chronic renal disease in survivors, necessitating renal replacement therapy in almost two-thirds of cases.
FOETAL HYDRONEPHROSIS
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Superintendent, ICH.
Sir,how frequently we have to followup the hydronephrosis case postnatally?