9 Causes Of Malformation In Babies (6 Can Be Avoided)

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The fertilization and development processes of a fetus have many delicate steps. The slightest alteration in one of them can cause anomalies. Obstetrician Guilherme Loureiro, responsible for fetal medicine services at Pro Matre Paulista, ranks the main causes of malformation in babies and advises what to do to avoid them.

What are the causes of malformation in babies?

Chromosome abnormalities

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Chromosomes are a long DNA sequence that hold the information that each cell needs to grow, develop and reproduce.

Naturally, human beings have 23 pairs of chromosomes. When the amount is different, they are born with syndromes that may include malformations.

The most common one is Down Syndrome which, although it is not a disease, causes low muscle tone and intellectual disability.

There are no ways to prevent this kind of abnormality.


Women with a late pregnancy have a higher chance of having kids with malformation, which is another non preventable cause of the condition.

The reason behind is that women are born with all of their eggs formed - they age at the same rate the woman does - so, the older the woman, the weaker her eggs' ability for cell division is.

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“For example, women at 35 have 0.5% chance of having a child with Down syndrome, while at 40, they have 1% and at 45, there is a 5% chance”, says the obstetrician.

Congenital anomalies

It is also possible that the baby is born with a random genetic alteration caused by hereditary reasons, like cleft lip. There are still no ways to prevent this type of malformation.

Raw food

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The doctor states that women that have never had toxoplasmosis can develop it during pregnancy when ingesting contaminated raw meat from mammals.

In this case, there is a chance the parasite will affect the baby and harm the development of their central nervous system. Therefore, it is best to wait nine months before eating that beef carpaccio.

Nutritional deficiency

Pregnant women nutritional deficiency can also have a baby with a malformation.

A known example of this situation is women who lack or present an excess of folic acid in the organism. Kids may be born with a defective neural tube, cleft lip or cleft palate.

Therefore, it is important to follow adequate prenatal care and, preferably, do bloods tests even before getting pregnant to evaluate the need for supplements.

Diabetes type 1 or 2

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Women with uncontrolled blood sugar levels during the preconception phase or on the third trimester of pregnancy have a higher chance of conceiving children with congenital malformations.

To avoid that, it is advised to keep levels of glucose under control even before getting pregnant.

Infectious diseases

Some infections contracted by pregnant women can be the cause of malformation in babies, such as infections caused by the cytomegalovirus and Zika virus.


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The doctor emphasizes that there are medications that can cause fetus malformation, like antiepileptics, which increase the risk of anomalies on the face, spine and central nervous system.

Another med that could cause these effects is isotretinoin, usually known by its commercial name Roaccutane. The risk is so high that it’s advised that the woman takes supervised pregnancy tests.

Some antidepressants also increase the risk of alteration as they influence the genes to not do what they should.

Therefore, seek medical assistance before taking any medication during pregnancy.


According to the specialist, another cause of malformation in babies is attending saunas because hot steam can lead to the rupture of fetal chromosome, causing syndromes.

Can smoking and drug use cause malformation?

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Smoking is not considered one of the causes of malformation, but it is not indicated to do so during pregnancy because it can hinder oxygen flow to the fetus, aging the placenta prematurely and affecting the baby’s growth.

The same goes for drug use by the mother, like crack and cocaine. “Marijuana can decrease the baby’s future perceptive intelligence”, says the doctor.

Translated article original published on VIX Brazil, by Mariana Riscala.