The Most Common Congenital Birth Defects and Risks for Developing Them
Congenital birth defects, also called congenital disorders, are abnormalities present in babies at the time of birth. They affect approximately six percent of births, according to the World Health Organization (WHO), and the defects range from mild to life-threatening. While some congenital birth defects can be treated, others may compromise a person’s health throughout their life. The vast majority of anatomic defects are now discovered in utero via ultrasound.
About 90% of severe birth defects occur in low- to middle-income countries with limited resources, likely due to a lack of access to medical care, nutritious diet, and dangerous environmental exposures. The WHO estimates that about 240,000 newborns around the world die each year due to congenital disorders, and 170,000 children between the ages of one month and five years old will die due to these disorders.
Risk Factors
While many congenital birth defects have unknown causes, others have risk factors that include:
• Genetic factors: A minority of congenital birth defects are caused by genetic defects and chromosomal abnormalities, which include chromosomal defects (too few or too many chromosomes), a mutation in a single gene, or an inherited gene. This risk increases when both parents are related by blood.
• Combination of factors: Sometimes, genetic and environmental factors combine to cause a birth defect, which is known as multifactorial birth defect.
• Environmental exposures: Environmental factors that increase the risk of genetic defects include exposures to pollutants and radiation, as well as exposure to infections (including rubella and syphilis) or drugs and alcohol in the womb.
The Most Common Congenital Birth Defects
Heart Defects
A heart defect is the most common type of congenital birth defect. This can range from a mild defect to a severe one that results in parts of the heart that are missing or malformed at birth. These defects may be diagnosed in the womb, although some may not be diagnosed until well into childhood. While the treatment will depend upon the type of heart defect, medical advancements in recent years have led to more people living longer lives with congenital heart defects.
Neural Tube Defects
The neural tube serves as both the developing brain and spinal cord in the early stage of pregnancy. During a healthy pregnancy, the tube will divide: The top part becomes the brain, the rest becomes the spinal cord. When the two parts do not close properly, a neural tube defect can occur.
The most common spinal cord defect is spina bifida, which can present with mild cases that do not cause disability to severe cases, which can affect leg movement and bladder function. A common type of congenital brain defect is anencephaly, a severe defect which causes a baby to be born without parts of the brain or skull.
Cleft Lip/Palate
If the tissue of the lip doesn’t close properly before birth, a cleft lip can result. This leaves an opening in the upper lip, which can range from a small slit to a larger opening that extends into the nose. A cleft palate occurs when the tissue on the roof of the mouth doesn’t close properly. Surgeries can treat a cleft lip or palate to minimize negative effects to breathing or speech.
Down Syndrome
When a baby has an extra copy of a certain chromosome—chromosome 21—they will develop Down syndrome. This can result in mental and physical challenges and developmental delays that vary in severity. Although it is a lifelong condition, people who have Down syndrome can receive services that address these challenges and positively impact quality of life.
Prevention of Congenital Defects
While many congenital defects have no known causes, taking some measures may reduce the chance for others. For example, to reduce the risk of having a baby with a congenital heart defect, the birth parent can take the following steps during pregnancy:
• Eat a nutritious diet including fortified foods that provide adequate folic acid or iodine intake.
• Take a daily prenatal vitamin for adequate nutrients and vitamins.
• Stop smoking and/or avoid being exposed to second-hand smoke, and don’t consume alcohol or drugs.
• Avoid exposure to harmful materials such as lead, radiation, and pesticides.
• Reduce the risk of infection by not consuming undercooked meat and raw eggs.
• Manage existing medical conditions, such as high blood pressure and diabetes.
• Be current on vaccines, especially the rubella vaccine, which should be given at least three months prior to conception to provide proper immunity.
Although congenital defects can’t be completely prevented, adopting healthy habits prior to conception and during pregnancy can help mitigate some risks. For those born with congenital defects, modern science continues to make advances and can provide treatment that allows many to live full and bright lives.