What Is Phocomelia?

Written by Hirania Luzardo
Medically Reviewed by Zilpah Sheikh, MD on July 01, 2025
4 min read

Phocomelia is a rare condition present from the time of birth. In this, people are born with arms or legs that are short or not fully formed. The hands or feet may be attached directly to the baby's trunk. It can affect one limb or more.

This condition can be genetic or caused by exposure to the drug thalidomide during pregnancy. You may also hear of various types of phocomelia. Phocomelia is a key feature of a condition called pseudo-thalidomide syndrome, or Roberts SC-phocomelia syndrome.

Phocomelia can't be reversed, but there are ways to help manage the condition.

Perhaps, the most well-known cause of phocomelia is a drug called thalidomide, which was once sold as a safe treatment for morning sickness, anxiety, and sleep problems.

But doctors found that thalidomide could cause serious birth defects such as phocomelia. In some cases, babies were born without limbs or did not survive. By the 1960s, thalidomide was banned during pregnancy. It's sometimes still used to treat certain cancers, complications of leprosy, and other conditions, but its use is tightly regulated. In cases that don't involve thalidomide, doctors often don't know what causes phocomelia. Some possible causes include:

  • Inherited gene mutations or changes
  • Gene changes that happen on their own when cells divide
  • Gene changes that develop after exposure to viral infections, X-rays, UV rays from sunlight, or other environmental triggers

Scientists have a theory that the shortened limbs, a feature of phocomelia, may result when blood vessel abnormalities disrupt the supply of blood to developing arms and legs.

Phocomelia doesn't look the same in everyone. Babies with the condition may have the following features:

  • Arms and/or legs may be very short or not visible at all.
  • The condition can affect all four limbs, just the upper or lower ones, or just one.
  • The hands or feet may attach close to the shoulders or hips.
  • The fingers or toes may be fused together, giving them a "flipper" appearance.

In addition to shortened or missing limbs, children with phocomelia may also have symptoms such as:

  • Trouble with learning or memory
  • A shorter-than-usual neck
  • A bulge near the brain called encephalocele
  • Vomiting that doesn't go away or severe headaches
  • High pressure inside the skull caused by extra fluid
  • Problems with the heart, kidneys, eyes, or ears
  • Problems with the formation of the uterus, kidneys, or heart
  • A low number of platelets, which makes it harder for the blood to clot‌

How serious phocomelia is and what its complications are vary a lot from person to person.

Babies born with phocomelia may face challenges early in life. Some are born prematurely, have low birth weight, or need help to breathe and eat in their first days.

As they grow, daily tasks such as getting dressed, brushing teeth, or walking may take more time or require special tools. 

Some have other developmental and medical issues, such as intellectual disabilities or heart, back, or intestinal abnormalities, that will require monitoring and treatment.

Phocomelia can't be cured. But several treatments can improve how limbs work and look, including:

Limb lengthening to help arms or legs grow closer to a typical length.

Surgery to rebuild missing or short bones using healthy bone from another part of the body, such as the fibula (a slim bone in the lower leg).

Surgeries to reshape or preserve a limb (sometimes called phoco-reduction).

Prosthetics to support movement and help with everyday activities.

Physical therapy and occupational therapy to build strength and improve mobility.

Phocomelia is a rare condition present from the time of birth. It affects how the arms or legs form. It can be caused by genetics or taking certain medicines during pregnancy, though doctors don't always know what cause it. While it can't be cured, treatments such as prosthetics, therapy, and surgery can help. With early care and support, children with phocomelia can build skills, gain independence, and manage everyday tasks more easily.

What was the survival rate of phocomelia?

Phocomelia is linked to high rate of stillbirths, especially in infants who also have other physical issues. One study found there were 24 stillbirths for every 85 live births of babies with phocomelia.

For those born with phocomelia, the rate depends on how serious the condition is and whether thalidomide caused it. As many as 40% of babies with severe abnormalities due to thalidomide die. 

What is the difference between amelia and phocomelia?

The difference between amelia and phocomelia is in how the limbs are affected. With amelia, the baby is born without one or more limbs entirely. Phocomelia means the baby is born with very short arms or legs, and the hands and feet may be attached directly to the torso.

How rare is phocomelia?

Phocomelia is very rare. It affects about 0.62 out of every 100,000 births.

Can you prevent phocomelia?

You can't always prevent phocomelia. Some cases happen because of genetic changes. These may happen on their own or could be caused by exposure to viruses, chemicals, or radiations. You can lower the risk greatly by avoiding the drug thalidomide during pregnancy. Check with your doctor before you take any medicine while pregnant.