Why can some 45-year-olds easily have a baby while much
younger women have difficulty becoming pregnant?
The answer, say Israeli researchers, could lie in their
Having a naturally conceived child past the age of 45 is
rare. But Dr Neri Laufer of the Haddassah University Hospital
in Jerusalem has discovered that some of those older mothers
seem to have a distinct genetic profile.
"We found a select group of genes that were significantly
different," Laufer told a medical conference Tuesday.
Using gene chip technology, he and his team compared the
genetic profiles of eight women chosen from 250 who had
had children past the age of 45 with profiles of six others
who had finished their families by the age of 30.
"These women appear to differ from the normal population
due to a unique genetic predisposition that protects them
from the DNA damage and cellular aging that helps age the
ovary," he said.
Conceiving naturally past the age of 45 is rare because
a woman's supply of eggs diminishes as she ages and approaches
the menopause, which normally occurs around the age of 50.
CHALLENGING THEIR SYSTEM
All the super-fertile women in the study were Ashkenazi
Jews, descended from the Jewish communities of central and
eastern Europe. Most had had six or more children, did not
use contraception and had a low miscarriage rate.
"They challenged their reproductive system until the menopause,"
said Laufer, who added that the distinct genetic fingerprint
was not unique to them.
He found a similar profile in Bedouin women who also had
children late in life.
"This unique group of super-fertile women may serve as
a model to learn about what makes them so successful in
terms of fertility," said Laufer.
But the researchers do not know whether the late age of
childbearing is linked to a delayed menopause or increased
longevity. They will try to find the answer to both questions
in further studies.
"We hope that better insights into these less than 50 genes
will help us in the future to develop better fertility agents
or the ability to manage infertility in women over 40,"
The research may also help scientists develop a prognostic
test to determine which women are likely to conceive in
Despite decreasing fertility and difficulty in becoming
pregnant at an older age, more women are putting off having
"People are getting pregnant older," Professor Michael
de Swiet, of Queen Charlotte's Hospital in London, told
the European Society of Human Reproduction and Embryology
In Britain in 2000-2002, about 10 percent of women were
35 years old during their first pregnancy, compared to just
3 percent a decade earlier.
Most fertility treatments are given to women between 30-39
years old. De Swiet said the idea age for having children
is between 25 and 35.