In bilateral renal agenesis, neither kidney develops in the womb. (‘Bilateral’ means two sides.)
Babies with this condition have no working kidneys.
Bilateral renal agenesis: tests and diagnosis in pregnancy
The 20 week antenatal ultrasound scan looks at your baby growing in the womb. If the person doing the ultrasound cannot see kidneys, or can only see a small amount of tissue where the kidneys should be, bilateral renal agenesis will be suspected.
The scan also measures the amount of amniotic fluid (or liquor), the fluid that your baby floats in. The baby’s kidneys start making urine and pass this out into the amniotic fluid. This fluid protects your baby from getting hurt from the outside and helps his or her lungs mature so he or she is ready to breathe after birth. If there is very little or no fluid, this is another sign of a serious problem with the kidneys, such as bilateral renal agenesis.
Referral
If bilateral renal agenesis is suspected, you will be referred to specialist healthcare professionals as early as possible in the pregnancy. They may include:
- foetal medicine specialist – a doctor who specialises in the health of unborn babies (foetuses)
- obstetrician – a doctor who specialises in pregnancy, delivering babies and the care of women after childbirth
- paediatrician – a doctor who treats babies, children and young people
- paediatric nephrologist – a doctor who treats babies, children and young people with kidney problems
- neonatologist – a doctor who specialises in newborn babies.
Further tests
You may need more ultrasound scans during the pregnancy to help find out whether it is bilateral renal agenesis.
What happens
Sadly, babies with bilateral renal agenesis are unable to survive. Some die during the pregnancy or within days after they are born.
In such situations, some people decide to terminate (stop) a pregnancy. This is a very personal decision. A healthcare professional will speak with you and support whatever decision you make.
Why does this happen?
Normal kidneys remove waste products from the body, and make sure the body has the right balance of water and salts. They also control blood pressure, help keep bones and teeth strong and healthy, and control the production of red blood cells. If there are no kidneys, the body cannot do this work.
While a baby is growing in the uterus (womb), he or she floats in amniotic fluid. This protects the baby from getting hurt from the outside and helps the lungs mature so that he or she is ready to breathe after birth. The baby swallows or ‘breathes in’ the amniotic fluid.
Normally, the kidneys develop and start making urine. The baby passes the urine out, adding to the amount of amniotic fluid. If the baby does not have kidneys, he or she cannot produce urine, and this leads to not enough amniotic fluid – this is called oligohydramnios. This can stop the lungs fully developing.
Will it happen in future pregnancies?
Doctors are trying to understand what causes bilateral renal agenesis. It is sometimes caused by a genetic mutation, which means that it may be inherited from the mother or father.
However, it is not usually likely that a future pregnancy will result in renal agenesis, or other problems with the kidneys. Your doctor or healthcare professional will be able to give you more information.
Further support
This can be a difficult and stressful experience for you and your family.
If you have any concerns or need additional support, speak with your doctor or nurse.