November 04, 2010
Researchers at Yale University and Albert Einstein College of Medicine have found an association in infertile women between type O blood and a diminished ovarian reserve, or the number of eggs that can be fertilized and result in pregnancy.
The study found these women with blood type O were at double the risk of having diminished ovarian reserve than women of other blood types, said Sangita Jindal, an assistant professor in the department of Obstetrics & Gynecology and Women’s Health at the Albert Einstein College of Medicine and one of the authors of the study.
But she cautioned: “I don’t want people with Blood Type O to think they’re half as likely to get pregnant. This is only in the infertile population and it’s only an association. We don’t know what the cause is.”
The study of 536 women’s blood types, obtained from data at Yale University under the supervision of Dr. Lubna Pal and data at Albert Einstein College of Medicine, found that both blood type O and A had an association with ovarian reserve.
In the case of infertile women with blood type O, they were twice as likely to have an elevated amount of FSH – a hormone produced by the pituitary gland that is related to the production of estrogen – as well as diminished ovarian/egg reserve, Jindal said in an interview with the Star.
High levels of FSH, or follicle-stimulating hormone, are a key indicator of having a low egg count.
However, researchers found that infertile women with blood type A in the study were 50 per cent less likely to have elevated FSH and diminished reserve, said Jindal who is from Ottawa and did her Ph.D. at the University of Toronto’s Department of Medicine at the Banting and Best Department of Medical Research.
Blood type B failed to demonstrate any relationship with FSH, the study found.
Jindal, also the lab director for the IVF program at Albert Einstein College, stresses it’s too soon to come to any conclusions about what the study’s results mean when it comes to helping infertile couples, which make up about 15 per cent of the population across North America, or one in six couples.
More research must be done to understand what the association means, Jindal said.
The researchers will need to look at blood types and the actual number of eggs produced through IVF in female patients, as well as a number of other variables before they can associate a response to a blood type, she said.
Once that is better understood, doctors working with infertile couples could one day use a woman’s blood type to help determine IVF treatment, Jindal said.
“I think we’re still grappling with why ovaries age. This is another piece of information we bring to the puzzle – yet another association.
“The field is still pretty new.”
The study, which Jindal and her co-authors hope will be published in a journal next spring, was recently presented at the annual American Society for Reproductive Medicine conference in Denver, Colo.