Times of India
26 October 2010
Women With Type O Blood Have Difficulty Conceiving Because Of High FSH Levels, Say Experts
A woman’s blood type could affect her fertility and influence her chances of becoming a mother, say researchers.
A new study has found that women with blood type O may find it harder to get pregnant as they have fewer eggs and eggs of poorer quality. However, women with blood group A seem to have better fertility prospects.
For the study, the researchers from Yale University and the Albert Einstein College of Medicine in New York tested 560 women, with an average age of 35, who were all undergoing fertility treatment.
They took blood samples from the women to measure levels of follicle stimulating hormone, a well known marker of fertility. FSH levels greater than 10 suggest a woman will have more difficulty conceiving.
A high FSH level indicates a diminished ovarian reserve, which refers to both the quality and quantity of eggs available.
The study found that women who were blood type O were twice as likely to have an FSH level greater than 10 than those in any other blood group. Some 44% of the British population are blood group O, the media in UK reported.
Lead researcher Edward Nejat said: "In both groups of women that were seeking fertility treatment, those with blood type O were twice as likely to have an FSH level over 10 than those with blood types other than O.
"We found that women with A and AB – women with the A blood group gene – were protected from this effect of diminished ovarian reserve.
"From the population we studied, and the fact it was two different centres and there was a good mix of patients ethnically and racially, we can say that blood type O was associated with an FSH level greater than 10 in women seeking infertility evaluation and/or treatment.
"Patients with blood type O seeking infertility evaluation at these centres have a higher likelihood to be diagnosed with elevated FSH and hence manifest diminished ovarian reserve."
The research did not quantify how much more difficult women with blood type O could find it to conceive.
People with blood group A carry the A antigen, which is a protein on the surface of the cell, but this is absent in people with O type.
Susan Seenan, of Infertility Network UK, welcomed the study. "Anything which might help couples avoid having to have fertility treatment has got to be good news," the Telegraph quoted her as saying. "If couples know that there is a possibility that they might have a fertility problem then perhaps they can address that earlier."
However, she cautioned that it was "early days" for the research and said more studies should be done before advising blood group O women to try for a baby earlier.
Tony Rutherford, chairman of the British Fertility Society, described the research as "interesting" in that it showed "a potential link" between blood type and fertility. But he too said a larger study needed to be carried out among the general population – not just those who had gone for help with fertility problems.
"We need to look at a prospective group of women to see if blood group affects your chance of getting pregnant," he said. He also said the link between blood group and other hormones that were better predictors of fertility needed to be examined. Age is the most important determinant of ovarian reserve, which tends to start dropping in the early 30s and then accelerate in the late 30s and 40s. Being obese is also known to affect the number and quality of eggs.