Hydronephrosis of the kidney in the fetus
Prenatal (prenatal) examination of the fetus makes it possible to diagnose anomalies in the development of the baby in the womb in 1% of cases, with 20% falling precisely on the genitourinary system. Half of such anomalies are manifested in the form of hydronephrosis, an expansion of the renal pelvis and calyces, which arises from a violation of the urinary flow.
The degree and development of hydronephrosis in a fetus may depend on various factors, but in any case, the detection of this anomaly is not a cause for panic, but for actions – prevention of development or treatment.
The bladder and kidneys of the future baby are detected with ultrasound from the 15th week of pregnancy, and in more detail they can be considered at the 18-20 week gestational period. It is then that the probability of detecting an anomaly increases.
Fetal ureters begin to form in the form of hard cords, which then turn into channels for unimpeded drainage of urine. Approximately on the eighth week of pregnancy until the completion of this process, the fetus begins to excrete urine, so there is a temporary obstruction (blockage) with the manifestation of hydronephrosis.
When the sewerage of the ureters is completed, this phenomenon is eliminated, and hydronephrosis must pass. But any factors that disrupt the formation of internal organs and fetal systems can lead to persistent hydronephrosis.
In the absence of other anomalies in the genitourinary system, in 80-85% of cases, congenital hydronephrosis is isolated and can cause a physiological expansion of the ureters at any stage of fetal development.
Methods for identifying this deviation in the development of the future baby can be divided into two groups:
- Laboratory methods
- Instrumental methods
In the first case, the fetal urine is evaluated. Correctly developing fetus detects hypotonic urine (such a density is lower than the density of blood plasma), and in renal dysfunction urine becomes isotonic. It increases the indicators of calcium, sodium and chlorides.
To assess the urine used vesicotsentez – puncture the walls of the bladder for fetal urine collection. This study allows you to accurately determine the condition of the fetus and the need for intrauterine intervention, but it can only be carried out in the case of serious malformations of the fetal urinary system.
The instrumental method for determining hydronephrosis in a fetus is prenatal ultrasound. This method has been used since 1970 and at the moment is an obligatory part of the complex examination of the fetus.
When ultrasonic abnormalities are detected, development of the structure and size of the kidneys, the volume of the amniotic fluid, the echogenicity of the renal parenchyma, the condition and filling of the bladder should be performed.