Birth Defects: Types, Causes, Diagnosis and Prevention

Birth defects are development abnormalities or abnormal functionality of organs in a baby while it is still in the mother's womb, in the developmental stage. There are more than 4000 birth defects which have been identified; some of them are minor that require no treatment or intervention, some of them are serious which require treatment or intervention. A few of them are fatal too!

Types of birth defects:

When the defect is in the organ formation, it is called 'Structural Defect' and when there is problem in the functionality or body chemistry it is called a 'Metabolic Defect'. Congenital Heart defects are the commonest known Structural Defect. Clubfoot, cleft palate & cleft lip, and spine defects (Spina Bifida) are other commonly occurring Structural Defects. Metabolic Defects prevent the body from properly breaking down food to create energy or prevents synthesis of Hormones, Enzymes etc. Common examples of metabolic birth defects are G6PD Deficiency, Phenylketonuria, Congenital Thyroid Defects etc.

What causes birth defects?

Though the cause of each birth defect is not known, some of the known reasons are:

1. Infections such as Rubella, Chicken Pox, Toxoplasmosis in the mother, especially in the first three months of pregnancy
   
2. Alcohol consumption and smoking by a pregnant mother
   
3. Certain medications taken in the first trimester of pregnancy
   
4. Genetic or chromosomal defects in either of the parents eg: Down syndrome, Dwarfism
   

How are birth defects diagnosed?

Tests like Ultrasonography, Amniocentesis, and Chorionic Villus Biopsy help in diagnosis of birth defects. These tests, when done at the right time during pregnancy, help in identifying birth defects. Of course, all these tests have limitations

Can birth defects be prevented?

Many birth defects can't be prevented, but there are some ways to lower the risk of having a baby with a birth defect.

• Folic acid supplementation during pregnancy, strictly under doctor's supervision, may help in preventing defects of the brain and the spine.
  
• Avoiding alcohol consumption and smoking during pregnancy
  
• Avoiding unnecessary medications during pregnancy, especially in the first three months. Any medication during pregnancy must be taken under the doctor's supervision
  
• Certain vaccines taken prior to pregnancy like Rubella, help in preventing Congenital Rubella Syndrome
  
• Pregnancy beyond 35-40yrs of age may increase the chance of birth defects
  

If there is a history of birth defect in the family then it is better to inform your Obstetrician regarding this so that proper genetic counselling and tests can be planned well in advance, and these will help minimize the chance of birth defects in the baby.

The author is Consultant Pediatrician, Hiranandani Hospital, Vashi - A Fortis Network Hospital

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