Do you know why people say it’s better to give birth while you’re young? That’s because advanced maternal age increases the risk of chromosomal anomalies in the fetus. Why do chromosomal anomalies arise, can they be detected before the birth of the fetus, and can they be prevented?
Types of chromosomal anomalies
The 23 pairs of chromosomes (that makes 46 in total) are the building blocks that make up a single human being. Chromosomes come from parents – one chromosome of each pair comes from one parent – and they contain the genetic information that is passed down to the offspring.
Of the 23 pairs of chromosomes, the 1st to the 22nd pair of chromosomes are what determines the baby’s physical traits. The 23rd pair of chromosomes is what determines the baby’s sex. When a baby doesn’t receive 23 pairs of chromosomes from the parents – for example, receiving more from one parent, or fewer – then this might result in birth defects as a result of chromosomal anomalies. The following are 3 representative birth defects caused by chromosomal anomalies:
Down’s syndrome/Trisomy 21
An extra copy of chromosome 21 causes the baby to grow up with Down’s syndrome. The characteristics of Down’s syndrome are flat facial features and growth retardation.
Edward’s syndrome/Trisomy 18
The trisomy 18 means that there are 3 copies of the chromosome 18 present. The extra copy can cause growth retardation, breathing difficulties, or heart disease. About 90% of babies born with trisomy 18 die within 1 year of birth – survival rate is low for infants with trisomy 18. It is the second most common birth defect due to chromosomal anomaly after Down’s syndrome.
Patau syndrome/Trisomy 13
A third and extra copy of the chromosome 13 results in trisomy 13. Like trisomy 18, trisomy 13 also leads to a growth retardation, breathing difficulties and heart disease. It is said about 50% of newborn infants die within a month, and 90% die within a year after being born.
Reasons why chromosomal anomalies arise
There is still no proper scientific explanation as to why chromosomal anomalies arise in some babies.
Whether there are chromosomal anomalies or not sometimes seem to be a matter of just pure luck. The sperm and the egg have 46 chromosomes each at the start, and then they undergo meiosis and have 23 chromosomes each. When they form a fertilized egg, the 23 chromosomes will match up with their pair and become connected to one another through this “crossing over”. During this process, things can go wrong and result in the wrong number of chromosomes in the fertilized egg, resulting in problems in the fetus.
Fertilized eggs with the chromosomal anomalies usually aren’t able to grow and pregnancy losses usually take place naturally. However, at times, the embryo is able to continue developing and though a natural pregnancy loss doesn’t occur, the baby might be born with chromosomal anomalies.
Is there any way to prevent chromosomal anomalies?
It is impossible to prevent chromosomal anomalies. Even modern science has no 100% foolproof method of preventing chromosomal anomalies from arising and thus, no way of preventing birth defects from arising. However, there are ways to try and reduce the risk of chromosomal abnormalities in fetuses.
Advanced maternal age increases the risk of chromosomal anomalies, so it’s recommended that women give birth young if they can and want to do so. Drinking alcohol, smoking and being overstressed cause cells to age faster and this can affect the genetic material you pass to your offspring. Avoiding such activities are said to contribute to the reduced risk of chromosomal anomalies.
Find out about chromosomal anomalies early
Chromosomal anomalies can be said to be accidental and to some extent, cannot be prevented. However, there are tests that you can consider taking to find out in the early stages of pregnancy if your child is at risk of having of such chromosomal anomalies. Talk to your practitioner about the tests that you’re hoping to take. Although some people stick by the principle that ignorance is bliss, it might be better to find out early so that you have time to take in and understand what’s going on.