[ 2006-09-28 09:45 ]
Taller women are more likely to have twins, according to a US
Gary Steinman, an obstetrician at New York's Long Island Jewish Medical
Center, compared the heights of 129 women who gave birth to twins or
triplets with the average height of women in the United States and found
women with multiple-birth pregnancies averaged more than an inch taller.
Steinman, whose study is being published in the September issue of the
Journal of Reproductive Medicine, said the reason seems to be an insulin-like growth factor, which
has been positively linked to both height and twinning.
Insulin-like growth factor is a protein that is released from the liver
in response to growth hormone. It increases the sensitivity of the ovaries
to follicle stimulating hormone, thereby increasing ovulation, the study
"Any circumstance that affects the amount of available insulin-like
growth factor so as to modify the sensitivity of the ovary to
follicle-stimulating hormone appears to govern the rate of spontaneous
twinning," Steinman said in a statement.
Previous studies have demonstrated that shorter people have
significantly lower levels of this protein and that countries with taller
women have higher rates of twinning compared to countries with shorter
In a previous study, Steinman found that women who consume animal
products, specifically dairy, were five times more likely to have twins.
Cows, like humans, produce insulin-like growth factor in response to
growth hormones and release it into the blood, and the protein makes its
way into their milk.
insulin-like growth factor