What Are Birth Defects?
Birth defects are a common condition, affecting one in every thirty-three babies born annually in the United States. The affected babies present with structural changes affecting different body parts. The severity of the condition varies, ranging from mild to severe. It can affect the appearance, body functioning, or, in some cases, both. Birth defects happen during fetal development within the mother’s womb. Most of the defects take place during the first trimester of pregnancy. Depending on the severity of the condition and the part of the body affected, the life expectancy may or may not be affected. Studies have shown that birth defects are a leading cause of infant death, accounting for 20 percent of infant deaths in the United States.
What Are the Causes of Birth Defects?
The exact etiology of most of the birth defects is still unknown. Some risk factors associated with the condition increase the chance of having a birth defect.
The causes include:
1. Genetic Changes:
Genetic or chromosomal abnormalities or changes can result in birth defects. In some cases, the defect can be passed on from the parent to the child (an inherited condition), or in other cases; the condition can occur randomly. The chromosomal changes include:
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Increase in Chromosomes - For example, in Down syndrome, the affected has an extra copy of chromosome 21.
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Missing Chromosome - For example, in the case of Turner syndrome, the affected has a missing X sex chromosome.
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Chromosome Deletion - In the case of Prader-Willi syndrome, the affected has a deletion of chromosome 15.
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Chromosome Relocation - Relocation or translocation of chromosomes is seen in Smith-magenis syndrome.
2. Exposure to Medications:
The intake of certain medications at the time of pregnancy or before increases the risk of developing birth defects.
Some of the common drugs that increase the risk of developing birth defects include:
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Warfarin.
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Antiepileptic drugs.
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Lithium.
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Isotretinoin is used for treating acne.
3. Substance Abuse or Chemical Exposure:
Exposure to certain substances or chemicals during pregnancy can lead to birth defects, These include:
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Pesticides.
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Alcohol.
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Smoking (cigarette smoke).
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Street drugs.
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Pollutants.
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Addictive substances (non-prescription drugs, caffeine, etc).
4. Complications During Pregnancy:
Complications that happen during pregnancy may lead to birth defects; these include:
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Infections like Zika infection may increase the chance of developing microcephaly during pregnancy. Cytomegalovirus infection and toxoplasmosis also increase the risk of developing birth defects.
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The increased age of the mother during pregnancy (greater than 34 years) increases the risk of developing birth defects.
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Lack of amniotic fluid around the fetus can increase the pressure on the fetus leading to lung damage.
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Damage to the amniotic sac during pregnancy may lead to limb anomalies and amniotic band syndrome (a condition in which loose uterine tissue bands surround the fetus).
What Are Some Common Birth Defects?
Some common examples of birth defects are:
1. Microphthalmia and Anophthalmia:
Microphthalmia and Anophthalmia are birth defects that affect the baby’s eye. Anophthalmia is when the infant is born without both eyes or one of them. Microphthalmia is when one or both eyes are small or not fully developed. The exact cause is unknown, and it may be diagnosed during pregnancy (routine ultrasound) or after birth.
2. Cleft Lip and Cleft Palate:
Cleft lip and palate defects are called orofacial clefts and are characterized by abnormal development of the infant’s lips and mouth. Surgical correction may be required in such cases.
3. Microtia and Anotia:
Microtia and Anotia are birth defects that affect the infant’s ear. A complete absence of the external ear characterizes Anotia. Incompletely formed or smaller external ears characterize Microtia.
4. Down Syndrome:
In most cases, Down syndrome occurs due to an extra copy of chromosome 21.
The physical features include:
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Short stature.
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Poor muscle tone.
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Small ears.
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Short neck.
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Protruded tongue.
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Palmar crease (a single line across the palm).
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Almond-shaped slanting eyes.
5. Craniosynostosis:
Craniosynostosis is a condition that occurs due to the early joining together of the infant’s skull bone before the brain is fully developed, leading to an abnormally shaped skull.
6. Diaphragmatic Hernia:
Diaphragmatic Hernia is characterized by a hole in the diaphragm. It can affect lung development and cause breathing problems in infants.
7. Esophageal Atresia:
Esophageal Atresia is a birth defect characterized by an abnormally developed swallowing tube (esophagus) in which the upper and lower esophagus are not joined. The condition can also result in breathing difficulties.
8. Microcephaly:
A smaller head characterizes Microcephaly, as does an often improperly developed brain.
9. Gastroschisis:
Gastroschisis is a condition characterized by a hole in the infant’s abdominal wall, and often, the intestine and other organs are found external to the baby’s body.
10. Muscular Dystrophy:
Muscular dystrophy is a genetic disorder characterized by muscle weakness that progresses over time.
11. Neural Tube Defects:
Birth defects affect the brain and spine and occur due to incomplete neural tube closure. The most common ones are spina bifida (a neural tube defect that results in mild to severe physical and intellectual disabilities) and anencephaly (a part of the baby’s skull and brain is missing).
12. Congenital Heart Defects (CHD):
Congenital Heart Defects are the most common type of birth defect. The condition affects the baby’s heart; both the functioning of the heart and its appearance can get affected. The severity of the condition varies, with critical CHD being the most severe form.
13. Limb Reduction Defects:
Limb reduction defects occur due to incomplete limb development during pregnancy. The treatment options vary and include surgical corrections, prosthetics, and rehabilitation.
How Is the Condition Diagnosed?
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Prenatal Diagnosis:
During pregnancy, the physician conducts screening tests to detect the risk of developing birth defects. If the screening tests suggest a risk of developing birth defects then diagnostic tests are done for confirmation. Screening tests include ultrasound and blood tests. Diagnostic tests include amniocentesis (amniotic fluid taken from the mother’s womb is used for checking for birth defects).
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Diagnosis after Birth:
Conditions such as cleft lip, cleft palate, microcephaly, microtia, microphthalmia, limb reduction defects, etc. are diagnosed on physical examination after birth. The newborn screening tests include blood tests (to determine genetic changes), hearing tests (to screen for hearing loss), and heart screening tests (to find heart defects).
What Are the Treatment Options?
The treatment options vary depending on the part of the body affected, the symptoms, and the severity of the condition.
The common treatment options include:
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Medications.
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Surgical correction.
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Prosthetics.
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Physical therapy.
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Speech therapy.
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Educational support.
Can the Condition Be Prevented?
In most cases, birth defects cannot be prevented. However, some steps can reduce the risk of developing birth defects.
These include:
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Proper prenatal care and routine periodic checkups during pregnancy.
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Avoid drinking alcohol, drugs, and smoking during pregnancy.
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Take 400 micrograms of folic acid daily during the entire pregnancy period.
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Taking measures to prevent infections during pregnancy.
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If any preexisting medical condition is present, make it under control before planning pregnancy.
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Any medication taken during pregnancy should only be taken under the consent of a healthcare professional.
Conclusion
Birth defects present structural and/or functional abnormalities in the newborn. It occurs due to changes during the fetal developmental stage during pregnancy. The exact cause is not known, however in most cases, genetic, environmental, and infectious factors increase the risk for poor development.
