Potter’s syndrome is a serious condition in which a baby develops with severely low or absent amniotic fluid, almost always because the kidneys fail to form or function properly during pregnancy. Without enough amniotic fluid, the baby’s lungs cannot develop normally, and physical compression in the womb leads to distinctive facial features and limb abnormalities. The classic form involves a baby born with no kidneys at all, a condition called bilateral renal agenesis.
How the Condition Develops
The sequence of events behind Potter’s syndrome starts with the kidneys. By the second trimester, a developing baby’s kidneys are the primary source of amniotic fluid because the baby swallows the fluid and urinates it back out. When the kidneys are absent, severely malformed, or blocked, the baby produces little to no urine, and amniotic fluid levels drop dangerously low. This fluid deficit is called oligohydramnios.
Amniotic fluid does more than cushion the baby. It plays a critical role in lung development. The baby “breathes” small amounts of fluid in and out of the lungs throughout pregnancy, and this stretching motion is what signals the lungs to grow. Without that fluid, the lungs remain small and underdeveloped, a problem known as pulmonary hypoplasia. At the same time, the walls of the uterus press directly against the baby without the normal fluid buffer, restricting movement and molding the face and limbs into characteristic shapes.
Types and Causes
Potter’s syndrome is classified into subtypes based on what went wrong with the kidneys:
- Classic Potter’s syndrome: The baby has no kidneys at all (bilateral renal agenesis). This is the most well-known form.
- Type I: Caused by autosomal recessive polycystic kidney disease, where both kidneys are massively enlarged with fluid-filled cysts.
- Type II: The kidneys are present but severely malformed and nonfunctional, a condition called renal dysplasia.
- Type III: Caused by autosomal dominant polycystic kidney disease, though this form typically causes problems later in life rather than before birth.
- Type IV: A blockage in the urinary tract (at the ureter or kidney pelvis) causes urine to back up and damage the kidneys, leading to a condition called hydronephrosis.
Some of these causes are genetic. Types I and III involve inherited mutations that cause polycystic kidney disease, meaning they can run in families. Bilateral renal agenesis can also have a genetic component, though it sometimes occurs without a clear inherited pattern. Type IV, caused by a physical blockage, is structural rather than genetic.
Physical Characteristics
Babies with Potter’s syndrome share a recognizable set of facial features often referred to as Potter facies. These include a flattened nose, a recessed chin, prominent folds of skin at the inner corners of the eyes, and low-set ears with unusually wide outer cartilage. These features develop because the baby’s face is compressed against the uterine wall for weeks or months without the cushioning effect of normal amniotic fluid levels.
Beyond the face, affected babies often have limb abnormalities caused by the same compression. Arms and legs may be positioned abnormally, and the hands and feet can appear clubbed or curved. The overall appearance reflects a baby who developed in an extremely tight space with little room to move.
How It’s Detected Before Birth
Potter’s syndrome is typically identified during routine prenatal ultrasound. The most obvious sign is severely low amniotic fluid, which makes the ultrasound image itself look unusual because amniotic fluid normally provides the contrast needed to see the baby clearly. A technician or doctor may also notice that the kidneys appear absent, abnormally shaped, or enlarged with cysts. In some cases, the bladder is not visible because no urine is being produced to fill it.
When these findings appear together, particularly very low fluid combined with absent or abnormal kidneys, the diagnosis is strongly suspected. Additional imaging or genetic testing may be offered to determine the specific type and guide conversations about what to expect.
Prognosis and Survival
The outlook depends heavily on the underlying cause and the severity of lung underdevelopment. In the classic form, where no kidneys are present, the condition has historically been considered fatal. Babies are either stillborn or survive only hours to days after birth because their lungs are too underdeveloped to support breathing.
For types caused by blockages or partial kidney function, the prognosis can be more variable. If some kidney tissue is working and amniotic fluid levels are not critically low, the lungs may develop enough to sustain life after birth, though long-term kidney problems are expected.
Experimental Treatment With Amnioinfusion
A recent clinical trial tested whether repeatedly injecting saline into the uterus (serial amnioinfusion) could replace the missing amniotic fluid and give the lungs enough room and fluid to develop. The trial, conducted at nine fetal therapy centers in the United States between 2018 and 2022, enrolled mothers carrying babies with bilateral renal agenesis, the most severe form.
The results were mixed. Of 18 pregnancies treated, 17 resulted in live births at a median gestational age of about 32 weeks. The amnioinfusions did help the lungs develop: 82% of the live-born infants survived at least 14 days and were able to start dialysis. However, survival dropped substantially over time. Only about half of the infants were still alive at 60 days, and just 35%, or 6 of the 17 live-born babies, survived long enough to go home from the hospital. Those who did survive were discharged on long-term dialysis at a median age of about 24 weeks.
The trial was stopped early because of concerns about the high rate of complications and mortality beyond the initial two-week window. Researchers concluded that while amnioinfusion can prevent lethal lung underdevelopment, the burden of having no kidney function at all creates additional life-threatening challenges that the procedure cannot address. For the babies who do survive, a kidney transplant remains the only path to life without dialysis.
Care After Birth
Babies born with Potter’s syndrome who survive delivery typically require immediate intensive care. Respiratory support, including mechanical ventilation, is almost always necessary because of underdeveloped lungs. If the baby has some kidney tissue but it is not functioning adequately, peritoneal dialysis (a process where fluid is cycled through the abdomen to filter waste) may be started in the first days of life.
For babies with type IV Potter’s syndrome caused by a urinary tract blockage, surgery to relieve the obstruction can sometimes improve kidney function significantly. Procedures to open a blocked valve or create a new outlet for urine can reduce pressure on the kidneys, potentially preserving enough function to avoid dialysis in the short term.
Long-term care for survivors centers on managing chronic kidney disease. This involves careful monitoring of growth and nutrition, maintaining the right balance of minerals in the blood, supplementing calcium and vitamin D, treating anemia, and managing blood pressure. Children whose kidney function continues to decline will eventually need dialysis or a kidney transplant, and transplantation is generally the preferred long-term solution when the child is large enough to receive a donor organ.