Blood group could affect women's fertility

A woman's chances of conceiving may be influenced by her blood group,
according to recent preliminary research in the US.

Researchers found that in women seeking fertility treatment with an average
age of 35, blood type O was linked to a lower egg count and poorer egg quality.
Meanwhile blood group A was associated with a more plentiful egg reserve of
higher quality.

Experts from Albert Einstein College of Medicine and Yale University
measured levels of follicle stimulating hormone (FSH) in blood samples taken
from over 560 women undergoing fertility treatment. Individuals of blood type O
were found more likely to have high levels of FSH than those with blood type A.

FSH is produced endogenously to stimulate follicles in the ovaries to
produce eggs. Fertility experts routinely associate high FSH levels with a low
egg count known as a 'diminished ovarian reserve'. The current findings suggest women of blood type O are twice as
likely to have an FSH level above 10 as those in any other
blood group.

According to lead author Dr Edward Nejat: 'Patients with blood type O
seeking infertility evaluation have a higher likelihood to be diagnosed with
elevated FSH and hence manifest diminished ovarian reserve'.

Within the UK population approximately 44 percent of individuals are blood
group O and 42 percent are group A. People with blood group A carry the A
antigen, a protein on the surface of the cell, but this is absent in
people with O type. The research did not quantify how much more difficult women
with blood type O could find it to conceive.

While FSH levels seemingly provide some indication of a women's egg reserve,
'a woman's age remains the most important factor in determining her success of
conceiving', according to Dr Nejat. Ovarian reserve tends to start dropping in
the early 30s and this further accelerates in the late 30s and 40s.

Tony Rutherford, chair of the British Fertility Society, called for
further large-scale research to both confirm the result, and to see if an
effect could be seen in women without diagnosed fertility problems trying to
conceive. 'This is the first time that I'm aware of that the researchers have shown a link between blood group and potential for fertility', he said.

The findings, based on patients at the Yale University IVF programme and
the Montefiore Institute in New York, were presented at the annual American
Society for Reproductive Medicine (ASRM) conference in Denver last week.