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Birth Defects

  • A medical condition, typically inherited, that occurs before or at birth
  • Visible birth defects include cleft lip and palate, craniofacial and limb anomalies
  • Surgery can fix some conditions; diagnosis before birth can help doctors address concerns quickly
  • Involves neonatal/perinatal medicine, Fetal Care Center, Prenatal Genetic Diagnosis Program

Birth Defects


About 3 percent of babies are born with one or more birth defects, also called congenital anomalies. Parents often grapple not only with proper diagnosis but making sure their child receives the best treatment available.

At Yale Medicine, we have highly skilled surgeons who use advanced techniques and technology to repair birth defects and help children live full lives. Plus, our researchers continue to work on advances to help pediatric patients.

What is a birth defect?

A birth defect develops when the structure of an organ is not formed correctly in the womb. Birth defects can be present in many forms, ranging from mild to severe, and a baby may be born with more than one.

If the defect is not detected in utero, it may be detected shortly after birth. Some birth defects are immediately visible, such as cleft lip, cleft palate, craniofacial anomalies and limb abnormalities. But others may be less conspicuous. Those types of birth defects may include congenital heart disease, diaphragmatic hernias and biliary atresia, which is a rare disease of the gallbladder and liver.

What are the risk factors for birth defects?

“When the structure of an organ isn’t formed properly, it can compromise normal function,” says Mustafa Khokha, MD, a Yale Medicine pediatrician. “The lungs have a very particular shape and structure. If that shape or structure is not formed correctly, then we can’t breathe properly.”

The causes of birth defects include inheritance, meaning it has been passed genetically from the parents, or by chromosome or gene abnormalities. In some cases, a mother’s environmental exposure during pregnancy could affect the unborn child. “During embryonic development, there are many instructions that are necessary to turn a very simple structure like an egg into a complex structure like our body,” Dr. Khokha says. “And if any one of those has a mutation in them, it causes an error in that construction process that can lead to serious birth defects.”

How are birth defects diagnosed?

Generally, birth defects are detected in utero by using ultrasound, which takes an echo or ultrasound of the mother’s womb. For more accurate detection, other tests such as chromosome analysis, whether performed on a blood sample or cells from the amniotic fluid, or placenta, are often suggested.

Can birth defects be treated?

Detecting birth defects in the womb is critical so that any health concerns can be addressed immediately after birth. While some birth defects remain very challenging to care for, even with current advances in pediatric care, the prognosis is good for children with many birth defects because surgical techniques and postoperative care have come a long way.

“One of the exciting things today is that we are now sequencing the genomes of children with birth defects and identifying the genes that cause those birth defects,” Dr. Khokha says. “And that’s really transformed the way we take care of these children because we’re starting to understand why they have birth defects in a way that we never could before.”

Can birth defects be prevented?

Every day researchers make strides in determining the causes of birth defects and how they can be prevented. That research is generating insight into how each of us is constructed because our genes provide major clues.

As researchers understand the disease process, they can potentially devise therapies to help the families and children who have birth defects. 

“For example, if we understand the gene that is causing the birth defect, we could council families and tell them, ‘Well, mom and dad are carriers of this disease, and your likelihood of having another child with this disease is high,’” Dr. Khokha says. “In that case, we could suggest to them that they get preimplantation genetics, do in vitro fertilization, and identify just those embryos that don’t have the genetic mutation, and prevent the disease from occurring. Alternatively, we might find that the mutation occurs just in the baby, in which case their chance of having another baby with the birth defects is extremely small, almost none.”

New sequencing technologies are making it an exciting time for the early detection and prevention of birth defects. Families wishing to take part in birth defects research can come to Yale Medicine.

What makes Yale Medicine’s approach to birth defects unique?

Yale Medicine takes a unique approach to identifying and treating birth defects, Dr. Khokha says. “We have all the latest surgical skills to try to repair the birth defect and to make these children as whole as possible,” he says.

“One of the things that’s most exciting about working at Yale Medicine is the ability to integrate our research and our clinical practice,” Dr. Khokha says. “So we see children with birth defects and provide some of the best care possible for these children. In addition, by using our gene sequencing technologies, we can study these children and answer questions about why they have their disease in a way that’s not possible elsewhere.”