• Sun. May 1st, 2022

Birth Defects and its causes, risk factors, common birth defects, and diagnosed

Birth Defects

Birth Defects

Birth defects are problems that develop when a baby grows in the womb. According to reliable sources in the United States, approximately 1 in every 33 babies is born with a birth defect.

Birth defects can be minor or severe. They may affect appearance, organ function, and physical and mental growth. Most birth defects are present within the first three months of gestation when the organs are still forming. Some birth defects are harmless. Others require long-term medical treatment. Severe birth defects are the leading cause of infant death in the United States, accounting for 20% of trusted sources of deaths.

Causes of birth defects

Birth defects can be a result of:

  • Exposure to certain medications and chemicals
  • Lifestyle choices and behaviors
  • Genetics
  • Infections during pregnancy
  • A combination of these factors

However, the exact causes of some birth defects are often unknown.


The mother or father can pass on genetic abnormalities to their child. Genetic abnormalities occur when a genetic defect is caused by a mutation or change. In some cases, a gene or part of a gene may be missing. These defects occur during pregnancy and are often preventable. A specific defect may be present throughout the family history of one or both parents.

Nongenetic causes

It is difficult or impossible to identify the causes of certain birth defects. However, certain behaviors greatly raise the risk of birth defects. These include smoking, drug use, and alcohol consumption during pregnancy. Other factors, such as exposure to toxic chemicals or viruses, also raise the risk.

The risk factors for birth defects

Pregnant women have some risk of delivering a child with a birth defect. Risk increases under any of the following conditions:

  • Drug use, alcohol consumption, or smoking during pregnancy
  • Family history of birth defects or other genetic disorders
  • Mother age 35 years or older
  • Adequate prenatal care
  • Use of some high-risk medications, such as isotretinoin and lithium
  • Untreated viral or bacterial infections, including sexually transferred infections

Women with pre-existing medical disorders, such as diabetes, are also at a higher risk of having a child with a birth defect.

Common birth defects

Birth defects are classified as functional or structural and developmental.

Structural defects are when a particular body part is missing or malformed. The most common structural defects are:

  • Spina bifida, when the spinal cord doesn’t develop perfectly
  • Cleft lip or palate, when there is an opening or split in the lip or roof of the mouth
  • Clubfoot, when the foot points inward instead of forwarding
  • Heart defects

Functional or developmental birth defects cause a body organ or system to fail to function properly. These often lead to intellectual or developmental disabilities. Functional or developmental birth defects include metabolic disorders, emotional problems, and nervous system problems. Metabolic disorders can cause problems in the baby’s physiology

The most common types of functional or developmental birth defects are:

  • Down syndrome causes delays in physical and mental development
  • Sickle cell disease occurs when red blood cells are malformed
  • Cystic fibrosis damages the lungs and digestive system

Some children experience physical problems associated with certain birth defects. However, many children do not show visible abnormalities. Defects can sometimes go undiagnosed even months or years after the baby is born.

Birth defects diagnosed

Many types of birth defects can be diagnosed during pregnancy. A health professional may use prenatal ultrasounds to help diagnose certain birth defects in the uterus. More in-depth screening options such as blood tests and amniocentesis (taking a sample of amniotic fluid) can also be done. These tests are usually given to women who have a high risk of pregnancy due to family history, advanced maternal age, or other known factors.

Prenatal tests can help determine whether the mother has an infection or other condition that is harmful to the baby. A physical analysis and hearing test may also help the doctor diagnose birth defects after the baby is born. A blood test called the newborn screen can help doctors diagnose some birth defects shortly after birth before signs occur.

It is important to know that prenatal screening does not always find defects when they are present. A screening test can incorrectly identify defects.  However, most birth defects can be diagnosed with certainty after birth.

Genetic counseling

A genetic counselor may advise couples with a family history of a defect or other risk factors for other disorders. A counselor can be helpful when you are having children or are already expecting them. Genetic counselors can determine the chances of your baby being born with defects by evaluating family history and medical records. They may order tests to analyze the genes of the mother, father, and baby.