The highest individual probability of having a child with Down syndrome is for older mothers (over 35), as the risk increases significantly with age (e.g., 1 in 100 by age 40), but most babies with Down syndrome are born to younger mothers (under 35) because they have more babies overall, making it the most common birth scenario. Other risk factors include parental carriers of genetic translocations and potentially insufficient folic acid, though age is the primary factor.
Down syndrome occurs in people of all races and economic levels. The risk increases with the mother's age (1 in 1250 for a 25 year old mother to 1 in 1000 at age 31, 1 in 400 at age 35, and about 1 in 100 at age 40). However, 80% of babies with Down syndrome are born to women under age 35 years.
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.
The risk of having a child with Down syndrome increases after a pregnant person is 35 years of age. But most children with Down syndrome are born to pregnant people under age 35 because they have far more babies. Being carriers of the genetic translocation for Down syndrome.
Down syndrome occurs in people of all races and economic levels, though older women have an increased chance of having a child with Down syndrome. A 35-year-old woman has about a one in 350 chance of conceiving a child with Down syndrome, and this chance increases gradually to 1 in 100 by age 40.
We evaluated 3,419 cases of Down syndrome in a 15-year period and found that the incidence of Down syndrome is influenced by paternal age. Paternal age has an effect on Down syndrome but only in mothers 35 years old and older.
These factors include geographic region, maternal education, marital status, and Hispanic ethnicity. Because the likelihood that an egg will contain an extra copy of chromosome 21 increases significantly as a woman ages, older women are much more likely than younger women to give birth to an infant with Down syndrome.
Family Planning
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 ...
NIPT has a high sensitivity, which means it is very good at correctly identifying cases where a chromosomal abnormality is present. For common trisomies like Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and Patau syndrome (Trisomy 13), NIPT often has a sensitivity of over 99%.
Global Down syndrome prevalence rate in 1990 and 2019, by gender. In 2019, the global age-standardized prevalence rate of Down syndrome was around 21.51 per 100,000 population. The prevalence rate of Down syndrome is slightly higher among males than females.
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.
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.
While females with Down syndrome are reported to be fertile or subfertile, males are reported to be infertile. To date, there are reports of three pregnancies that were fathered by two male Down syndrome patients (1, 2). We report a case of a nonmosaic Down syndrome male who fathered a normal child.
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.
Today the average lifespan of a person with Down syndrome is approximately 60 years. As recently as 1983, the average lifespan of a person with Down syndrome was 25 years.
This finding of the paternal age influence on Down syndrome suggests that there is a sperm contribution to the trisomy; increased paternal age may lead to an increased frequency of chromosome abnormalities in sperm, according to Dr. Fisch.
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.
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.
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?
Studies suggest that the risk of giving birth to a child with Down syndrome increases as the mother ages. Females who are 35 or older are more likely to have a child diagnosed with Down syndrome or another type of genetic condition.
Chromosomal Changes That Can Cause Down Syndrome
A higher chance NIPT result does not mean the baby has one of the conditions but it is very likely. At least 90% (9 out of 10) of women who receive a higher chance NIPT result for Down's syndrome will be carrying a baby who has the condition. After a higher chance NIPT result, you will be offered diagnostic testing.
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.