Potter syndrome, or Potter sequence, refers to the characteristic physical features of a fetus or newborn that develop as a direct result of oligohydramnios (a severe lack of amniotic fluid) or anhydramnios (a complete absence of amniotic fluid) in the womb. The key to understanding Potter sequence is to recognize that from the second trimester onward, amniotic fluid is almost entirely composed of fetal urine. A baby continuously swallows the fluid, which is then processed by their kidneys and excreted back out into the amniotic sac. This cycle is absolutely critical for normal development.

A helpful analogy is to think of the amniotic sac as a personal, custom-fit “swimming pool” in which the baby develops. The baby’s own kidneys are the “faucets” that keep this pool filled with water (fetal urine). This fluid-filled environment is not just for floating; it is essential. It provides a cushion to protect the baby and gives them the space they need to move their limbs and grow without being compressed by the walls of the uterus. Most critically, the baby constantly “breathes” the amniotic fluid in and out of their lungs. This process of inhaling and exhaling fluid is what stretches the lung tissue and allows the lungs to develop and mature, much like inflating and deflating a balloon over and over to make it strong and pliable.

In the conditions that lead to Potter sequence, the “faucets” the baby’s kidneys are either missing or completely non-functional. No urine is produced, and the swimming pool remains empty. This has two catastrophic consequences:

1. Without the fluid cushion, the baby is compressed by the uterus, leading to a characteristic set of physical deformities.
2. Without fluid to breathe, the lungs cannot develop. They remain tiny, solid, and non-functional, a condition called pulmonary hypoplasia. It is this severe lack of lung development that is the ultimate life-limiting factor in Potter sequence.

In my experience, explaining Potter syndrome to families is incredibly delicate. It refers to a group of features caused by reduced or absent amniotic fluid due to poor fetal kidney development.

The direct cause of Potter sequence is always the lack of amniotic fluid. The underlying cause is any condition that leads to a complete failure of fetal urine production. This is almost always due to a catastrophic problem with the development of the baby’s kidneys.

The most common underlying causes include:

• Bilateral Renal Agenesis (BRA): This is the classic cause, where both of the baby’s kidneys fail to form at all during embryonic development.
• Autosomal Recessive Polycystic Kidney Disease (ARPKD): A severe genetic disorder where the kidneys are massively enlarged and completely replaced by thousands of tiny cysts, rendering them non-functional.
• Obstructive Uropathy: A severe, early blockage in the baby’s urinary tract, such as from posterior urethral valves, that prevents any urine from exiting the bladder into the amniotic sac. The kidneys may have formed, but the plumbing is completely blocked, leading to the same outcome of anhydramnios.

Clinically, the most common cause I’ve encountered is bilateral renal agenesis, where both fetal kidneys fail to form, leading to severe oligohydramnios and the cascade of physical abnormalities.

A baby develops the features of Potter sequence due to having a severe congenital abnormality of their renal system. This is not a condition that is contagious or acquired. Its origins lie in early fetal development.

Many of the underlying causes of renal failure, such as bilateral renal agenesis and ARPKD, are genetic disorders.

• They are typically inherited in an autosomal recessive pattern.
• This means that for a baby to be affected, they must inherit two copies of a mutated gene associated with kidney development, one from their mother and one from their father.
• The parents are almost always unaffected carriers, meaning they each have one normal copy of the gene and one mutated copy and are perfectly healthy.
• When two carriers of the same faulty gene have a child, there is a 25% chance with each pregnancy that the child will inherit two mutated genes and be affected with the condition.

Because both parents must carry a mutation in the same rare gene, the chances of having a child with an autosomal recessive condition that can lead to Potter sequence are higher in populations where marriage between close relatives, such as first cousins, is a common cultural practice. This is because related individuals have a greater likelihood of carrying the same inherited genetic traits.

In my experience, Potter syndrome arises during fetal development, often due to a genetic mutation or a spontaneous error affecting kidney formation, it’s not inherited in most cases.

The signs and symptoms of Potter sequence are the physical characteristics that result directly from the lack of amniotic fluid and compression in the womb. These features are often recognizable on a detailed ultrasound or immediately at birth.

The classic collection of features, often called Potter facies, includes:

• A flattened, “squashed” facial appearance.
• A flattened, beak-like nose.
• A recessed chin (micrognathia).
• Large, low-set ears that are deficient in cartilage and may seem “floppy.”
• Prominent skin folds (epicanthal folds) at the inner corners of the eyes.

Other physical findings resulting from compression and lack of movement include:

• Limb Abnormalities: The hands and feet are often malformed or held in abnormal positions, such as clubfoot.
• Pulmonary Hypoplasia: This is the most significant and defining feature of the sequence. It is the severe underdevelopment of the lungs. This is not a visible external sign but is the reason the condition is fatal.

During prenatal care, I’ve seen warning signs like low amniotic fluid and abnormal fetal positioning on ultrasound after birth, the classic “Potter facies” and respiratory distress are key findings.

The diagnosis of Potter syndrome and its underlying cause is almost always made during pregnancy on a prenatal ultrasound.

• The Key Ultrasound Finding: The diagnostic process often begins when a routine mid-trimester ultrasound reveals severe oligohydramnios or anhydramnios (very little or no amniotic fluid).
• Confirming the Cause: A sonographer will then perform a detailed examination to try to find the cause of the absent fluid. In classic Potter sequence, the key findings are:
  • Persistent inability to visualize fetal kidneys.
  • The persistent inability to visualize the fetal bladder filling with urine.

When these findings are present, a diagnosis of a fatal renal abnormality leading to Potter sequence is made. The diagnosis should be confirmed at a high-risk perinatal center with expertise in maternal-fetal medicine. Genetic counseling will be offered to the parents to discuss the diagnosis, prognosis, and potential for identifying the specific genetic cause through further testing, which can be important for understanding the risk in future pregnancies.

Clinically, I typically diagnose it prenatally through ultrasound findings such as absent kidneys and oligohydramnios. Genetic testing may help rule out associated syndromes.

It is essential for parents to understand that Potter sequence, due to the severe and universal presence of pulmonary hypoplasia (underdeveloped lungs), is considered a condition that is incompatible with life after birth. There is no surgery or medical intervention that can grow a baby’s lungs in the womb when there is no amniotic fluid. A baby born with no functional lung tissue cannot be resuscitated or supported by a ventilator.

Given this devastating prognosis, the entire focus of care shifts away from curative or life-prolonging interventions and toward perinatal palliative care.

• The Goal of Palliative Care: The goal is to provide comfort, honor the baby’s life, however short, and provide comprehensive emotional, psychological, and spiritual support for the parents and family.
• Management of the Pregnancy: A multidisciplinary team, including maternal-fetal medicine specialists, neonatologists, genetic counselors, social workers, and spiritual care providers, will meet with the family. They will provide clear information about the baby’s condition and support the parents in making decisions about the remainder of the pregnancy and a plan for delivery. The focus is on aligning medical care to the family’s values and wishes.
• Care After Birth: The plan after delivery is focused entirely on comfort care. This means:
  • The baby is dried, kept warm, and placed in their parents’ arms.
  • No heroic measures, such as resuscitation or mechanical ventilation, are performed, as these would be futile and would only prolong the dying process.
  • The family is given private time to be with their baby, to hold them, to take pictures, and to create memories.
  • The medical team focuses on ensuring the baby is kept comfortable and free from any distress, allowing for a peaceful and dignified passing in the arms of their parents.

Support for the Family

The grief associated with a fatal prenatal diagnosis is profound. It is imperative that families have access to support. This includes bereavement counseling, and connecting with support groups for perinatal loss, which can provide a community of understanding from other parents who have walked a similar path.

I’ve sadly seen that in severe forms, particularly with bilateral renal agenesis, treatment is supportive, survival beyond birth is rare due to lung underdevelopment.

A diagnosis of Potter syndrome is one of the most heartbreaking pieces of news an expectant family can receive. It represents a cascade of developmental failures stemming from the absence of kidney function and amniotic fluid, leading to a condition that is ultimately incompatible with life. The medical journey following this diagnosis is not one of fighting for a cure, but one of shifting to a philosophy of compassionate, comfort-focused care. The model of perinatal palliative care provides families with the medical honesty, emotional support, and gentle guidance needed to navigate their grief, to honor the life of their child, and to find a path toward peace and healing during an impossibly difficult time.

National Organization for Rare Disorders (NORD). (2022). Potter Syndrome. Retrieved from https://rarediseases.org/rare-diseases/potter-syndrome/

National Institutes of Health, Genetic and Rare Diseases Information Center (GARD). (2021). Potter syndrome. Retrieved from https://rarediseases.info.nih.gov/diseases/7421/potter-syndrome

Society for Maternal-Fetal Medicine (SMFM). (n.d.). Palliative Care. Retrieved from https://www.smfm.org/topics/palliative-care