What are the types of birth defects?

Birth defects are classified into two main groups: structural and functional abnormalities:

• Structural birth defects: affect how the body is built. Examples include cleft lip or cleft palate, heart defects, limb abnormalities (eg clubfoot) and neural tube defects (eg spina bifida).
• Functional birth defects: affect how the body works. These include: intellectual and developmental disabilities, behavioural disorders, speech or language difficulties, seizures, deafness, metabolic disorders (eg  hypothyroidism), degenerative disorders that manifest later in life and progress with age (eg muscular dystrophy) and syndromes such as Down syndrome, Prader-Willi syndrome, and Fragile X syndrome. Some birth defects may include both structural and functional abnormalities.

What causes birth defects?

While birth defects may be causes by genetics or the environment or a combination of the two, for the majority (>50%) the cause remains unknown. There are a number of risk factors that may increase one’s chance of having a child with a birth defect, including:

• Genetics: Genes are the instructions (or recipe!) that make our bodies work. Changes (called mutations) in genes can cause disease and syndromes, such as Fragile X syndrome, that result in birth defects. Other birth defects result when there is a change to the structure or number of chromosomes (the structures that hold the genes) which results in an addition or reduction in the genetic material. An example is Down syndrome where an extra chromosome 21 is present in all the cells of the body.
• Maternal infections: maternal infections such as cytomegalovirus (CMV), rubella, syphilis and toxoplasmosis increase the risk of the child being affected by a birth defect.
• Exposure to medications, chemicals, or other agents during pregnancy: use of certain medicines, including both prescribed and over the counter medications as well as recreational drugs, alcohol use and smoking during pregnancy are associated with an increased risk of birth defects. Exposure to these   should be avoided three months before pregnancy, during pregnancy and after birth while breast feeding.
• Maternal illnesses: Women with chronic, long term conditions such as diabetes and epilepsy need to be closely monitored during pregnancy including their use of prescribed medications to manage these conditions.
• Obesity:  Women who are obese are at a higher risk of having a baby affected by birth defects, including CHD and spina bifida. Having too much body fat can make it difficult to identify and diagnose birth defects via an ultrasound.
• Advanced Maternal Age: Pregnant women over the age of 35 years are at a higher risk of having a birth affected by a chromosomal disorder such as Down syndrome.

Prevention is better than cure

There are many birth defects that can be prevented by taking appropriate measures before and during pregnancy.

So, what can you do?

• Get a preconception check-up.
• Take folic acid – Pregnant women and women who are planning a pregnancy should take folic acid daily three months before pregnancy and in the first trimester to prevent most neural tube defects.
• As soon as you suspect you are pregnant, seek early antenatal care (ANC) and continue regularly throughout the pregnancy. In South Africa there are eight ANC visits during pregnancy with the first visit within the first 20 weeks of pregnancy.
• Learn about your family health history to identify any genetic conditions that may be inherited through the family.
• Maintain a healthy weight.
• Avoid smoking, drinking and drug use during pregnancy.
• Avoid harmful substances in your environment such as pesticides, radiation, second-hand smoke, fish containing large amounts of mercury.
• Prevent infections. If you become ill with a cold or the flu, please speak to your doctor or a pharmacist about what you may safely take to alleviate the symptoms.

How can we help?

This year Rare Diseases South Africa has again partnered with WBDD to raise awareness of the burden of birth defects worldwide and particularly in South Africa. The latest estimate of the birth prevalence of birth defects in South Africa is approximately 49 per 1000 births or one in 20 births, which equates to 55,000 babies born with a birth defect annually (Malherbe et al, 2021). This highlights the need to raise awareness in South Africa around birth defects and their impact on individuals, families, and the country at large.

For WBBD 2022 a toolkit providing ideas and activities that can be done individually or with other organisations to increase awareness is available here. More information is available at www.worldbirthdefectsday.org