The kidneys are an integral part of the body’s excretory system and perform the primary function of purifying the blood by removing toxins and nitrogenous waste products. These toxins are formed in the body as the byproducts of the various metabolic activities. The kidneys filter the waste material and water which flows through the ureters into the urinary bladder, where it is stored till it is excreted via the urethra.
Routine maternal sonography scans, especially during the early months of pregnancy may be associated with incidental findings like enlargement of the kidneys. This condition is also referred to as hydronephrosis and the severity of the condition may range from mild to severe.
During pregnancy, the fetus receives all of its nutrition from the placenta. The kidney system in the fetus develops by 10-12 weeks after which it starts producing urine; however most of the nutrition and excretion of waste is done via the umbilical cord. Generally, this urine is released into the amniotic fluid, which plays an important role in protecting the fetus and also provides nutrition.
Enlargement of the kidney is one of the most common problem found on ultrasound examination. In most cases, the condition may resolve and a kidney may return back to normal size on subsequent scan examinations or after birth. However, it is important to keep a track and evaluate the condition on regular basis.
Causes Of Enlarged Kidneys In Fetus
While in some cases, enlarged kidney may not be associated with any apparent cause, there are some common causes that have been identified,
- Vesicoureteral reflux: This condition is associated with faulty functioning of the valves which are present at the juncture of the ureters and the urinary bladder. The valves are meant to prevent urine from flowing backwards (i.e. from the bladder into the ureters), however defect in these valves can cause a reflux which in turn may result in hyderonephrosis or enlarged kidneys.
- Ureteropelvic Junction Obstruction: This condition is associated with the obstruction of the junction where the kidneys are connected to the ureters. This condition usually results in one kidney being enlarged.
- Bladder outlet obstruction: This condition is associated with blockage of the opening of the bladder into the urethra. In boys, abnormal fold of skin along with posterior urethral valve can result in the obstruction of the bladder opening.
- Ureterocele: This is associated with underdevelopment of the ureter, which creates a bulge and the condition is referred to as ureterocele.
Finally nerve damage can result in poor coordination of nerve signals which control the bladder. This condition is often associated with Spina Bifida or other forms of birth defects.
What Care To Take For Enlarged Kidneys In Fetus?
During the pregnancy there is a need to constantly monitor the progression of the condition. Regularly performing parental scanning is mandatory. In some cases amniocentesis or chorionic Villus Sampling may be performed to rule out genetic deformities like Down’s syndrome.
In addition the mother should ensure that she consumes adequate amount of water, to avoid shortage of amniotic fluid. Once the baby is born, the child should be immediately examined by a pediatric urologist. Surgical intervention may be required in cases of obstructions or other conditions.