Congenital anomalies of the kidneys and urinary tract are among the most frequently ultrasound-indentified malformations in the prenatal period.

Thanks to the introduction of fetal ultrasound in pregnancy screening programs, the diagnosis of these abnormalities in utero allows early manegement. In fact, prenatal diagnosis allows evolutionary control of the pathology and appropriate counseling, putting in place the best therapeutic strategies at birth. However, the predictive value of prenatal ultrasound findings is often difficult to establish.

Therefore, the investigators want to evaluate the postnatal outcomes in fetuses prenatally diagnosed with unilateral nephropathy, specifically the rate of live births, gestational age at delivery, neonatal weight, and the need for admission of the infant to the neonatal intensive care unit (NICU).

The data collected will allow investigators to assess postnatal outcomes in fetuses prenatally diagnosed with unilateral nephropathy, identifying the prenatal ultrasound findings most associated with poor postnatal prognosis to define the role of ultrasonography in predicting outcomes of fetal nephropathy.

Clinical data of single-pregnancy patients who were referred to the Pregnancy at Risk Outpatient Clinics of our center between 2007 and 2023 will be considered.

These patients were evaluated with serial ultrasound checks at the outpatient clinics for the presence of suspected unilateral nephropathy that emerged during morphologic ultrasound performed between the 19th and 21st weeks of gestation. Therefore, we will analyze the ultrasound data that emerged during serious outpatient checkups, the delivery data of patients who delivered at our center, and the postnatal data of newborns.

Information on the following will be collected for each patient:

• Age
• Type of suspected nephropathy (pyelectasis, hydronephrosis/hydroureteronephrosis, multicystic kidney, dysplasia)
• Gestational age at the time of suspected diagnosis
• Gestational age at the time of diagnosis
• Assessment of amniotic fluid
• Centile of affected kidney (<5°, normal, >95°)
• Centile of unaffected kidney (<5°, normal, >95°)
• Presence of associated abnormalities in the other anatomical districts
• Performance of invasive prenatal diagnostic methods (Karyotype analysis and CGH-array)
• Progression of nephropathy
• Involvement of contralateral kidney
• Gestational age at the time of delivery
• Mode of delivery (vaginal/caesarean section)
• Sex of the newborn at birth
• Infant's weight at birth
• Ph of newborn at birth
• APGAR index at 5 and 10 minutes
• Possible admission to neonatal intensive care unit.

Inclusion Criteria:

• Single pregnancy
• Age greater than or equal to 18 years
• Detection of Unilateral Renal Abnormalities during Confidential Ultrasound
• Delivery performed at the O.U. of Obstetrics and Prenatal Age Medicine
• Acquisition of informed consent form

Exclusion Criteria:

• Request for voluntary termination of pregnancy

Patients evaluated with serial ultrasound checks at the outpatient clinics of this center for the presence of risk factors for unilateral fetal nephropathy will be considered.