What is Renal Agenesis ? 

What is Bilateral Renal Agenesis?


Bilateral Renal Agenesis is when both kidneys fail to develop during the early weeks of pregnancy.

Most people have 2 kidneys, one on the left side of the body and one on the right, which along with the bladder, ureters and urethra form the renal / urinary system, a system which eliminates waste from the body in the form of urine.

The renal system has other important functions which include regulating the volume of blood in the body and the blood pressure, it also regulates blood PH levels which stops the blood becoming too acidic or too alkaline.

And finally the renal system helps control the levels of natural salts, called electrolytes, and metabolites, which are products from metabolism, which also occur naturally in the body. All of these functions keep our blood and body in a state of balance every day.













Bilateral renal agenesis is usually diagnosed at a 20 week anomaly scan where there is an absence of both kidneys seen on scanning and either Oligohydramnios, which is too little amniotic fluid or Anhydramnios which is the complete/near complete absence of amniotic fluid.

During pregnancy, the mothers body will provide amniotic fluid until around 12-14 weeks. After this time, the baby will begin to swallow the fluid and then, with the presence of a renal system, pass the fluid out as urine. This is a continuous cycle until the baby is born. 

Swallowing the amniotic fluid creates a positive pressure in the baby's developing lungs, this pressure enable the lungs to develop, grow and mature ready for birth.

With the absence of any kidneys, any fluid which has been swallowed is absorbed by the baby until there is either very little or no fluid remaining, resulting in under-developed lungs called Pulmonary Hypoplasia.

The placenta will replace the kidneys in filtering waste out of the baby's blood until the baby is born.