Blood Type O Linked With Fertility Problems in Women

A study published online in the journal Human Reproduction suggested that blood type can clue in on a woman’s reproduction capabilites.

Based on the tests conducted of a group of women on their 30’s, those with blood type O are more likely to fewer egg cells. Type O blood is the most common type in the United States where it comprises 45% of the population.  Forty % is type A, 11% for type B, and the remaining 4% is type AB.

Could your blood type determine your fertility? (photos from
Could your blood type determine your fertility? (photos from

This research, though, according to its author Lubna Pal, who researches on reproductive endocrinology at the Yale University School of Medicine, is not meant to scare women that their blood type can compromise their reproduction abilities. It actually aims to open chances for earlier diagnosis and therefore  make necessary preventive measures.

How was the research done?

Pal and her colleagues studied the follicle-stimulating hormones (FSH) levels of 544 women seeking fertility help in Connecticut and New York, whose average age was 35. After taking into account the effects of age, they discovered that women with blood type O were twice as likely to have high FSH levels compared to those with blood types A and AB.  FSH levels high enough to indicate they had diminished ovarian reserve. Very few women with blood type B participated in the study so the researchers were not able to determine statistically if their ovarian reserve was affected.

What does  high FSH level mean?

High FSH level could indicate a diminished ovarian stock in  women. Usually, a woman’s ovarian reserve starts to diminish in the late 30’s and 40’s but there is a subgroup of women in which this change can occur early.

Is it that conclusive?

The study only included women who sought fertility treatments and could not be applied to all women. Research also still have to determine if this relationship between blood type and fertility is available to all women in all parts of the world. The researchers stated the possibility that the same identifier molecule in blood cells could be a factor. Blood types A, AB and B  have enzymes  that raises a flag on the pole to indicate the blood group, in Blood Type O, however, there is no such indicator.

Richard Fleming, PhD, the scientific director of the Glasgow Centre for Reproductive Medicine says “That the results do seem quite surprising and stark in the distribution that you see between the blood groups.” However, he cautions that the FSH method isn’t the most accurate for measuring fertility. “It is fairly good at assessing extremes of egg reserve, but it can’t differentiate between normal and high and perhaps not even low-normal. “If women have fertility concerns,” he says, “get their Antimullerian Hormone (AMH) measured, not their FSH. It is a more precise marker of ovarian reserve,” he says. Routine testing could determine fertility problem risks, regardless of blood type.


Further researches will still have to be done to determine the connection between blood type O and diminished ovarian reserve. The researchers are fairly aware of this. For starters, the study should be done healthy populations, and if the result is replicated, that’s the only time then that women with blood type O should start worrying that their biological clocks  started ticking at an earlier age compared to others.

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