Women with blood type O less fertile, says new study

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 per cent of the UK population are blood group O, the British media reported.

Lead researcher Dr 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."

Tony Rutherford, chair of the British Fertility Society, was quoted as saying, "This is the first time that I am aware of that researchers have shown a link between blood group and potential for fertility."