Unlikely partners: blood type and IVF success rate
When undergoing in vitro fertilisation (IVF), there seems to be one million and one things that can influence the chance of success. The factors at play include age, specific type of infertility, the length of time a couple has been trying for a baby and the number of IVF cycles they’ve had – among other things.
All the factors at play make the likelihood of successful IVF treatment, pregnancy and birth more like a game of numbers than a medical miracle. In fact, there are even a few special calculators that help couples pin-point their likelihood of IVF success.
And it now seems like the list of factors influencing IVF success rates can boast a new addition. A woman’s blood type.
What exactly is a ‘blood type’?
There are four main blood types in humans: A, B, AB and O. Which blood type a person is depends on which type of marker they have on their red blood cells. These markers are called antigens and they send signals to the body to let the immune system know not to attack anything with that marker. Different types of markers identify people as different blood types.
Surprisingly, a research study published last month in the Journal of Assisted Reproduction and Genetics has shown that a woman’s blood type can influence her chances of giving birth to a healthy baby after IVF treatment.
The study – led by Dr. Michelle Goldsammler – found that women who belong to the blood type groups B or AB are almost twice as likely as women with blood types A or O to give birth to a live baby after IVF treatment.
Basically, this means women who have a B marker in their blood are at an advantage when it comes to IVF.
Blood type can provide even more clues about a woman’s chances of getting pregnant.
The study found that women with blood type O were more likely to have a diminished ovarian reserve – which occurs when a woman’s ovaries contain fewer eggs than expected for her age. The researchers were able to measure the lower than normal egg count as it is typically accompanied by an elevated level of the follicle stimulating hormone (FSH).
This isn’t the first time blood type has been linked to a lower than normal egg count. A previous study also found a link between blood type O and a diminished ovarian reserve.
What’s more, women with blood type A were three times more likely to experience ovulation (where an egg is released from the ovaries) that is irregular, abnormal or absent all together – compared to women with blood type O.
The researchers even made sure to check that it could not have been other factors influencing their results. They made sure the mother’s body mass index, age, type of infertility or other factors influencing the outcome of IVF could not be the cause of their findings.
Goldsammler’s study looked at the cases of 626 women who had undergone IVF treatment at two centres in north-east America between 2007 and 2009. And the study is the first of its kind to identify this unusual link between blood type and a woman’s chance of giving birth after IVF treatment.
But what might be the reasons behind these bizarre findings?
Well, as their findings are so novel and unusual, Goldsammler and her team can only speculate as to what their results could be caused by. They believe that the different markers that identify different blood types might lead to the production of slightly different molecules inside the body. Some of these molecules could be better news for egg count, the regular release of eggs from the ovaries and live IVF births than others.
So what does all this mean for women undergoing IVF treatment?
At the minute drugs that stimulate ovulation are administered during IVF. This may help us to avoid the problems caused by a lower than normal egg count or abnormal ovulation. So this is good news for women of blood types A or O – who are more inclined to experience these problems!
But, on the whole – and as the results are still so new – scientists need to do more research to determine exactly what is going on. Once the reasons behind the results are clearer, it might be possible to use the effects of different blood types to our advantage when it comes to IVF.