The urinary system makes urine and removes it from the body. It includes the kidneys, ureters, urethra and the bladder. The kidneys make urine. The urine then travels through small tubes called ureters to the bladder. The bladder then empties the urine via urethra.
At 10 to 12 weeks of pregnancy, your developing baby begins to make urine. The baby’s urine normally leaves the bladder and goes into the amniotic sac of fluid that surrounds him or her. The amniotic fluid that surrounds and cushions a baby during pregnancy is mostly made of fetal urine.
A normal amount of amniotic fluid is a good sign of normal urinary function. When the amniotic fluid is low, this can mean there is a problem with the way the baby’s kidneys are working.
Image credit: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
The cause of urological problems is often not known. The conditions are referred to as congenital, meaning it happens before your baby is born. Urinary problems may occur alone or with other syndromes or birth defects.
A problem in the urinary system may be found during routine prenatal ultrasound but sometimes it is discovered after the baby is born. If your doctor suspects a problem, additional tests may be ordered. These may include:
• Fetal echocardiogram: A fetal echocardiogram is a special ultrasound used by a pediatric heart doctor (cardiologist) to look closely at your baby’s heart and surrounding blood vessels.
• Fetal MRI (magnetic resonance imaging): This type of imaging gives more detailed pictures of your baby’s organs.
Some congenital conditions are because of changes in DNA, or a baby’s genetic make-up. The doctors may suggest genetic testing to find out more about your baby’s DNA.
• Cell-Free Fetal DNA testing: Your doctor can take a sample of your blood to look for copies of fetal (baby) DNA. This is only a screening test. A positive result means that there could be problems with the DNA. This should be confirmed with another test to be sure of the result. Other testing can be done before or after birth depending on the needs of the baby.
• Amniocentesis: A small sample of the amniotic fluid that surrounds the baby in the womb is taken and tested for DNA problems. This test is usually done in the middle of the second trimester. An amniocentesis can be used to confirm findings on the cell-free fetal DNA test.
• Testing the baby: After birth, a test is done with a sample of your baby’s blood to look for chromosome problems. This is called either a “karyotype” (basic chromosome study), or microarray (a more detailed look and all genes).
If a test finds you are carrying a baby with a problem in the urinary system, you will continue to receive care from your obstetrician. Your obstetrician may refer you to the Ohio Fetal Medicine Collaborative (OFMC), which will help you connect with a team of experts at an area fetal medicine clinic or children’s hospital.
There, you will meet with a multidisciplinary team including neonatologists (doctors who specialize in treating newborns), pediatric urologist and or pediatric nephrologist and nurses to learn more about your baby’s care after he or she is born. Nurse coordinators will help answer your questions and concerns, guide you through your pregnancy, and prepare you for what to expect.
Most problems in the urinary system do not need treatment before birth, but do require frequent monitoring by a high risk obstetrician. A normal amount of amniotic fluid around the baby during pregnancy is reassuring. In rare cases, if the fluid gets very low, your physician will talk to you about whether there are any treatment options during the pregnancy.
Your doctor will watch your pregnancy closely. You will deliver your baby at a hospital that is ready to care for high- risk babies like yours. You should discuss your plans for labor and delivery with your obstetrician. Contact your doctor right away if you have any concerns.
Hydronephrosis: means a stretching in the area of the kidneys where urine collects. Hydronephrosis is not a specific diagnosis. Instead, it means that urine is overfilling the kidney. Some may refer to hydronephrosis as “swelling of the kidney.” Hydronephrosis may be caused by a blockage in a part of the kidney. A leaky valve in the ureters may also cause it. The leaky valve causes the urine to flow back from the bladder into the kidneys. In many children, the cause is never known. Often times when hydronephrosis is found in the prenatal period, the kidneys are normal after birth.
Hydroureter: is a condition in which the ureter is swollen. It can be due to the leaky valve or other conditions of the kidney.
Posterior Urethral Valves: is a congenital obstruction of the urinary tract. This condition occurs only in boys and affects about 1 in 8,000 babies. Posterior urethral valves (PUV) are excess flaps of tissue in the urethra. This excess tissue can block or reverse the flow of urine and can affect all of the urinary tract organs including the urethra, bladder, ureters and kidneys.
Vesicoureteral reflux (VUR): is the condition in which urine backs up from the bladder into the ureters and occasionally into the kidneys. Most children outgrow VUR. The goal of treatment for children with VUR is to prevent kidney infections and possible kidney damage.
Lower Urinary Tract Outlet Obstruction: is a rare condition that is caused by a blockage in the lower urinary tract, usually below the bladder. The baby is not able to release urine into the amniotic fluid and amniotic fluid levels can become very low. The most common cause of lower urinary tract obstruction in boys is posterior urethral valves. The long-term health of these infants depends on the severity of the effects from the low level of amniotic fluid.
Multicystic dysplastic kidney (MCDK): is a condition in which the kidney has been essentially replaced by multiple cysts. Most of the time, multicystic kidneys occur only on one side (left side). In this case, your child’s properly functioning On ultrasound, the kidney appears like a bunch of grapes with very little kidney tissue. The kidney usually has no function. Most of the time, multicystic kidneys occur only on one side (left side). In this case, your child’s properly functioning kidney can provide the required amount of amniotic fluid. Sometimes, it occurs on both sides, and these cases are very serious. It is generally thought to be caused by a urinary tract obstruction early in development during pregnancy.
Polycystic kidney disease (PKD): is an inherited genetic disorder. Clusters of cysts form in both kidneys. Polycystic kidney disease can also cause cysts in the liver and problems in other organs, such as the heart and blood vessels in the brain. The most serious complications of polycystic kidney disease are reduced kidney function and high blood pressure.
Bladder exstrophy: is an abnormality present at birth in which the bladder and associated structures do not form properly. If the abdominal wall does not correctly join during development, a baby can be born with the bladder and other structures exposed on the outside of the body. The condition is very rare. Bladder exstrophy usually involves several systems within the body, including abnormally shaped and weakened lower abdominal wall muscles; displacement of the belly button, usually immediately above the defect and lower than normal on the abdominal wall; shortened penis in boys; narrow vaginal opening in girls. Bladder exstrophy is treated surgically. Several surgical treatment options are available depending on the severity of the condition. Surgery is recommended after the baby is born.
After your baby is born, an ultrasound or other tests may be done to check on your baby’s urinary system. Some babies will need specialized attention in the neonatal intensive care unit after birth depending on the urinary problem. Some conditions will be treated with observation, some with medicine, and in some cases, surgery.
It is important that a pediatric urologist see your baby. The pediatrician in the hospital will let you know when your baby needs to be seen by a pediatric urologist; this is usually when your baby is 2 to 3 weeks of age. A kidney and bladder ultrasound or other tests may be done at that time.
Your baby will need regular follow-up appointments to measure growth, development and nutrition. You will want to find a local pediatrician to take care of the routine checkups, immunizations, and doctor’s visits. The program coordinator can help if needed. The pediatric urologist will provide follow-up care for your baby’s medical or surgical needs.