How genetic birth defects occur

Some genetic defects occur because of a mutation between one gene, or a missing part of a chromosome. There can also be birth defects if the baby has too few or too many chromosomes.

Other ways to get a birth defect are listed; lack of nutrients, infections during pregnancy, exposures to medicines or toxic substances, or if the person pregnant with the baby is obese or has health problems. (health problems do not always lead to birth defects.)

Several environmental causes for birth defects

​An environmental cause can include drugs, alcohol, or a disease the mother has that can increase the chance for the baby to be born with a birth defect. An agent that can cause a birth defect is known as a teratogen. Multifactorial birth defects are caused by a combination of genes and environmental exposures.

When does a premature birth occur? What problems do tiniest babies face?

Premature babies are most likely to have chronic illnesses, examples of this are; infections, asthma, feeding problems, blindness, or severe lung problems.