Older mothers have a higher chance per pregnancy, but most babies with Down syndrome are born to younger mothers (under 35) because they have more babies overall, though increased paternal age might also play a role, and a family history of Down syndrome (especially translocation type) increases recurrence risk. While maternal age is the most recognized risk factor, Down syndrome can happen to anyone, regardless of race or economic status.
Although women older than 35 years of age make up a small portion of all births6 in the United States each year, about one half of babies with Down syndrome are born to women in this age group. This likelihood increases as age increases.
In almost all cases, Down's syndrome does not run in families. Your chance of having a baby with Down's syndrome increases as you get older, but anyone can have a baby with Down's syndrome. Speak to a GP if you want to find out more. They may be able to refer you to a genetic counsellor.
Down syndrome is a genetic condition caused when an unusual cell division results in an extra full or partial copy of chromosome 21. This extra genetic material causes the developmental changes and physical features of Down syndrome. The term "syndrome" refers to a set of symptoms that tend to happen together.
In the interim it has become clear, primarily by family linkage studies tracing DNA markers along the length of chromosome 21q between parents and children in DS families that the majority of T21 DS cases inherit the extra chromosome 21 from their mother (more than 90%) while in only a minority (less than 10%) the ...
The rate of Down syndrome for both maternal and paternal age greater than 40 years is approximately 60 per 10,000 births, which is a six-fold increase compared with maternal and paternal ages less than 35 years of age. In this age group, the paternal contribution to Down syndrome was 50 percent.
Your risk of having a baby with Down syndrome increases as you get older, especially if you are age 35 or older. However, most children with Down syndrome are born to women under age 35 because younger women have far more babies. Being a carrier of a certain type of Down syndrome.
You can't prevent Down syndrome since it's a genetic condition. To learn more about your risk of having a child with a genetic condition, talk to your healthcare provider about genetic testing.
Down Syndrome Statistics by Country in 2025
Ireland – Ireland has the highest number of babies with Down syndrome, 27.5 out of 10,000 born there. Ireland has more children born with Down syndrome than other countries due to factors like older mothers, fewer prenatal screenings, cultural and ethical values.
Common physical signs of Down syndrome include a flat face, eyes that slant up, a short neck, small hands and feet, poor muscle tone, and loose joints. Common health problems in childhood include hearing loss, sleep apnea, ear infections, eye diseases, and heart defects.
However, certain indicators can be observed during an ultrasound, which may suggest the possibility of Down syndrome. These Down syndrome signs are called 'soft markers' and could include aspects like nuchal translucency thickness or other physical traits.
Of the people with Down syndrome in the United States: 67% are non-Hispanic and White, 13% non-Hispanic and Black, 16% Hispanic, 3% Asian or Pacific Islander, and 1% American Indian or American Native.
Down syndrome is caused by the presence of an extra chromosome number 21 in the cells of the developing baby. In an unscreened population, about one in every 700 babies is born with Down syndrome. Usually, it is not inherited, so a baby can be affected even if there is no history of Down syndrome in the family.
The prevalence rate of Down syndrome is slightly higher among males than females. This statistic shows the age-standardized prevalence rate of Down syndrome worldwide in 1990 and 2019, by gender.
Down syndrome is caused by a random error in cell division that results in the presence of an extra copy of chromosome 21. The type of error is called nondisjunction.
Unfortunately, most of the available literature is focused on maternal risk factors, and the only certain risk factors for the birth of a child with DS are advanced maternal age at conception and recombination errors, even though the molecular mechanisms leading to chromosome 21 nondisjunction are still a matter of ...
The number of people is probably between 13,000 and 15,000. This means that in a group of 10,000 people in Australia, there are just over 5 people with Down syndrome. This is about the same as in other countries such as the UK. For every 1100 babies born in Australia, 1 will have Down syndrome.
Age is the only factor that has been linked to an increased chance of having a baby with Down syndrome resulting from nondisjunction or mosaicism. However, due to higher birth rates in younger women, 51% of children with Down syndrome are born to women under 35 years of age. (De Graaf et al., 2022).
Mosby's Medical, Nursing and Allied Health Dictionary gives an average IQ of between 50 and 60 for Down's syndrome individuals although IQ scores of 120 have been found in some individuals with the syndrome.
However, there is no evidence of a decreased incidence of births of children with Down syndrome, and some studies actually provided evidence for a slight increase in incidence of births of children with Down syndrome, while other studies report no changes pre- and post- supplementation [23-26]. On the other hand, one ...
What causes birth defects?
Risks for chromosome abnormalities by maternal age
The risk of chromosomal abnormality increases with maternal age. The chance of having a child affected by Down syndrome increases from about 1 in 1,250 for a woman who conceives at age 25, to about 1 in 100 for a woman who conceives at age 40.
Some studies have also shown increased rates of chromosomal abnormalities in fetuses of fathers over the age of 50.
If you're over the age of 35, your pregnancy may be considered high risk due to “advanced maternal age.” This simply means you are more likely than younger women to have certain conditions and complications that may put you and your baby at risk.
Fetal ultrasound during pregnancy can also show the possibility of Down syndrome. But ultrasound is not 100% accurate. Problems from Down syndrome may not be seen with ultrasound. Diagnostic tests are done by looking at cells in the amniotic fluid or from the placenta.