BIRTH DEFECTS

Birth defects, also known as congenital anomalies, are physical abnormalities that develop before the birth of a child. They normally become apparent within the first year of life.

What are birth defects?

Birth defects are abnormal growth changes in your body that happens during fetal development. These changes can affect any part of your child’s body. Not all birth defects are visible.

While some birth defects can be life-threatening, the impact they have on your child’s life varies based on their diagnosis. Some birth defects only change your child’s appearance, while others can affect the way they think, move, and function.

Some of the most common birth defects include, but aren’t limited to, the following:

• A cleft lip and/or cleft palate.
• Bone growth abnormalities that cause short stature, missing limbs, or scoliosis.
• Congenital heart conditions.
• Chromosome abnormalities (Down syndrome, Turner’s syndrome, Klinefelter syndrome etc.
• Clubfoot.
• Fetal alcohol syndrome
• Sickle cell anemia.

               CAUSES AND RISK FACTORS

There is often no explanation for a birth defect. They all occur while the baby is still developing in the womb. They usually arise during the first three months of pregnancy while all the organs are developing. Some defects may occur later in pregnancy, such as limb differences caused by the amniotic sac constricting a limb and affecting growth.

Causes are:

• Genetic and chromosomal factors
• Exposure to harmful substances (teratogens)
• Nutrition
• Others

Genetic and chromosomal factors

• Birth defects can be a gene mutation for no known reason.
• Chromosomes and genes may be abnormal. These abnormalities may be inherited from the parents, who may either be affected by the abnormalities or who may be carriers of the genes that cause the abnormalities.
• Carriers are people who have an abnormal gene for a disorder but who do not have any symptoms of the disorder.
• However, many birth defects are caused by new chromosome abnormalities or gene mutations that arise in the fertilized egg and are not inherited from the parents.
• Birth defects caused by genetic factors often include more than just an obvious malformation of a single body part.
• Examples of this include:
• Chromosomal abnormalities
• Single-gene defects
• Multifactorial issues

Exposure to harmful substances (teratogens)

• Some birth defects are caused by exposing the fetus to drugs or alcohol during pregnancy.
• Some medical conditions such as uncontrolled diabetes can increase the risk of your baby having birth defects. Babies of older parents have a higher incidence of birth defects.
• A teratogen is any substance that can cause or increase the chance of a birth defect. Teratogens include:
• Radiation (including x-rays)
• Certain drugs-Isotretinoin, Antiepileptic medications (valproic acid),Lithium, Warfarin
  • Toxins (including alcohol)
• The majority of pregnant women who are exposed to teratogens have healthy babies. The occurrence of a birth defect is determined by trimester, the quantity, and for how long the pregnant woman was exposed to the teratogen.
• Exposure to a teratogen most commonly affects the fetal  organ that is developing most rapidly at the time of exposure.
• For example, exposure to a teratogen during the time that certain parts of the brain are developing is more likely to cause a defect in those areas than exposure before or after this critical period.

Nutrition

• Keeping a fetus healthy requires maintaining a nutritious diet.
• For example, insufficient folic acid (folate) in the diet increases the chance that a foetus will develop spina bifida or other abnormalities of the brain or spinal cord known as neural tube defects.
• A cleft lip (a separation of the upper lip) or cleft palate (a split in the roof of the mouth) is also more likely to develop.
• Obesity in the mother also increases the risk of a neural tube defect.

Infections

• Certain infections in pregnant women can cause birth defects.
• Whether an infection causes a birth defect depends on the age of the foetus at the time of the exposure to the infection.
• The infections that most often cause birth defects are:
• Chickenpox(varicella)
• Cytomegalovirus
• Erythema infectious(parvovirus B19 infection, fifth disease)
• Herpesvirus
• Rubella(German measles)
• Syphilis
• Toxoplasmosis(which can be transmitted in cat litter)
• A woman can have one of these infections and not know it because some of these infections can cause few or no symptoms in adults.

OTHERS  

• Older age
• Have had frequent miscarriages or stillbirths
• Have had other children with chromosome abnormalities or birth defects or who died in infancy for unknown reasons.

DIAGNOSIS

A healthcare provider can diagnose a birth defect during pregnancy, after your child is born or later during their life when symptoms become apparent. Testing can confirm a diagnosis.

• Before birth- Ultrasonography, blood tests, amniocentesis, or chorionic villus sampling
• After birth- Physical examination, ultrasonography, computed tomography, magnetic resonance imaging, and blood tests.

Before birth

Before birth, doctors assess whether a woman is at increased risk of having a baby with a birth defect (Prenatal Diagnostic Testing).

The chance is higher for women who have the risk factors  may need monitoring and special tests to find out whether their baby is developing normally.

• Ultrasonography of the foetus is commonly done during pregnancy.  This imaging tests can often detect specific birth defects.
• Sometimes blood tests can also help. For example, a high level of alpha-fetoprotein in the mother’s blood may indicate a defect of the brain spinal cord, or certain other organs.
• More recently, doctors are using a test called Non invasive prenatal screening(NIPS)it is a  cell-free foetal DNA analysis.
• In this test, a sample of a pregnant woman’s blood is analysed to determine whether her foetus has certain genetic disorders.
• NIPS can be used to detect an increased risk of trisomy 21(Down syndrome), trisomy 13, or trisomy 18, and certain other chromosome abnormalities.
• Doctors usually do further testing when an increased risk of a gene abnormality is detected.
• Amniocentesis(removing fluid from around the foetus) or chorionic villus sampling (removing tissue from the sac around the developing fetus) may help confirm a suspected diagnosis.

After birth

• After birth, the doctor does a physical examination of the newborn.
• During this examination, the doctor examines the newborn skin, head and neck, heart and lungs, and abdomen and genitals and assesses the newborn’s nervous system and reflexes.
• Some new-borns have a physical appearance that suggests a certain disorder.
• Imaging tests, such as ultrasonography, computed tomography(CT), and magnetic resonance imaging (MRI), may be done based on the results of the physical examination and screening tests.

PREVENTION

It is not possible to prevent every congenital anomaly. Some have no obvious cause, while some have a link to maternal health.

Maintaining good health and limiting risk factors can reduce the chance of health problems for the infant.

TREATMENT

• In general, there isn’t a complete cure for birth defects, especially genetic conditions.
• If your child’s symptoms are severe, treatment can help lower their risk of life-threatening consequences.
• Minor congenital anomalies do not require treatment.
• Prenatal testing may frequently discover anatomical abnormalities in the womb and assist medical professionals, parents, and those who care in planning.
• Congenital anomalies can cause lifelong disability.
• The child may need additional care or support to live the fullest possible life. This can involve ongoing surgeries or long-term medication.
• However, severe structural anomalies often need surgery shortly after birth.

OUTLOOK

• You can’t prevent most birth defects, but you may lower the risk by taking precautions before and throughout your pregnancy.
• Remember that you are not alone.
• Your doctors and nurses understand the difficulties of raising a kid with a birth defect. They will discuss screening tests, medicines, and other options for assisting your kid in reaching their full potential.