Antenatal hydronephrosis tests before birth
The 20 week antenatal ultrasound scan looks at the baby growing in the womb and measures the size of the renal pelvis. Antenatal hydronephrosis may be suspected if this is larger than usual.
The ultrasound cannot give precise information about the problem or what is causing it. Although your doctor will not always know how your baby will be affected at birth, they are less likely to have serious problems if:
- they are growing well in the womb
- no other problems have been found
- the amount of amniotic fluid (the liquid that the baby floats in when in the womb) is normal
Often, the expectant mother will need more ultrasound scans during her pregnancy. These will check whether the problem goes away or gets worse.
Referral
Your obstetrician may refer you to specialist healthcare professionals, such as a paediatric nephrologist (a doctor who treats children with kidney problems) or a paediatric urologist (a surgeon who treats children with problems of the urinary system). You can speak with these doctors about possible complications and their management.
Antenatal hydronephrosis tests after birth
You may need to come back to the hospital for your baby to have imaging tests (scans). These use special scanners that take pictures of the inside of their body.
Ultrasound scan
The first test is normally an ultrasound scan, which is similar to the scan mothers have in pregnancy. It looks at the shape and size of the kidneys and other parts of the urinary system. A small handheld device is moved around your baby's skin. A machine attached to the probe directs sound waves into their body – your child cannot feel these. These sound waves are turned into pictures that can be seen on a screen.
Other tests
Your doctor may also arrange a DMSA scan, which checks for any damage in the kidneys, and/or a MAG3 scan, which is used to find out how well urine is draining from each kidney. These are normally done when a baby is a few months old. In each test, a chemical that gives out a small amount of radiation (energy) is injected into one of your baby’s blood vessels. A special camera takes images (pictures) of your baby’s kidneys.
An MCUG (sometimes called a VCUG) checks how your baby is passing urine, and whether there is any reflux (when urine passes back up towards the kidneys). A thin flexible tube called a catheter is passed through your baby’s urethra and a dye is put through to reach the bladder. This does not hurt your baby. A special X-ray machine takes a series of images of your baby’s bladder while it is emptying.
Antenatal hydronephrosis treatment before birth
In most cases, no treatment is needed before birth.
In a very small number of cases, an operation may be recommended during pregnancy if there is little or no amniotic fluid around the baby growing in the womb. Your healthcare team will talk with you about this.
Antenatal hydronephrosis treatment after birth
Most babies can be discharged home as normal.
A small number of babies who had antenatal hydronephrosis in the womb have complications after birth. These babies may be monitored or treated in a neonatal unit, a special area of the hospital for newborn babies.
Occasionally, a baby needs an operation to correct the problem that is causing the hydronephrosis. If your baby needs treatment, a paediatric urologist will explain what will happen.
Preventing and treating UTIs
Some babies are at higher risk of urinary tract infections (UTIs). In rare cases, frequent UTIs may cause damage to a kidney.
Your baby may need to take a small dose of antibiotic medicine each day – this is called a prophylactic antibiotic. Antibiotics kill the bacteria (germs) that cause UTIs, and so help prevent these infections.
Sometimes UTIs can happen even when your child is taking these antibiotics. It is important that UTIs are diagnosed and treated quickly to try to prevent them causing kidney damage. If you think your child has a UTI, contact your doctor or local NHS services.
Follow up
Many babies with antenatal hydronephrosis are followed-up in clinic or hospital to check that there are no long-term problems.
About the future
In most cases, antenatal hydronephrosis does not cause any problems for the pregnancy or birth, and the baby and mother will not have any long-term problems.
Your child will be able to do all of the things that other children their age do. They can go to nursery and school and can play with other children and stay active.
Your healthcare team will speak with you and your family about any long-term effects. This depends on the severity of the hydronephrosis and the cause.
Long-term effects
A small number of children who had antenatal hydronephrosis caused by other problems have long-term problems with their bladder or kidneys. Your doctor will give you more information.
Further support
This may 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.