​Natural Killer Cells and Miscarriage.

What are natural killer cells?

Natural killer cells (NK cells) are part of the white blood cell family and they play a vital role in defending our bodies against disease and infection. All of the organs in the human body have NK cells, and a woman’s uterus has a huge number to prevent infection getting into this very important reproductive organ. In essence, we are all animals and the basic purpose of our lives is to reproduce and pass on our genes to the next generation. Our reproductive organs are therefore very important in evolutionary terms.

Not only do NK cells help prevent infection but they also aid in conception. They can recognise a growing embryo as a ‘foreign but friendly’ group of cells/tissues and they do not attack them. This is obviously very important if a pregnancy is to be successful.

Natural Killer Cells and fertility.

Some women have an abnormally high number of these NK cells in the uterus and this can cause a big problem if they are trying to conceive. Rather than seeing the embyo as ‘foreign but friendly’, they may attack it and this may lead to infertility and recurrent miscarriages.

In some incidences, NK cells may even prevent implantation in the first place. If you have had recurrent miscarriages then you should ask your GP to check your levels of NK cells. I have a friend who had tests done after her 4th miscarriage and she discovered this was her issue. She is now 6 months pregnant after being treated.

Treatment for high Natural Killer Cells.

It could be as simple as placing you on steroids to calm your immune response to foreign cells. Steroids may reduce the number of NK cells present in the uterus to within normal range, thus allowing you to conceive and maintain a pregnancy. Your doctor should refer you to a specialist if you are found to have high NK cell levels, as treatment needs to be balanced. Treatment should reduce NK cell number to prevent damage to your precious baby, but your body must still be able to prevent infection of the uterus. By week 10 of a pregnancy your baby will start producing its own steroids so treatment can slowly be tapered off from week 12 or so. You may also be given progesterone treatment and baby aspirin. 

To find out more about Natural Killer cells and other infertility issue or reasons for miscarriage, this is a great book recommended by lots of ladies on popular trying to conceive forums. Amazon customers have given it 4.5 out of 5 stars. and you can buy a copy from Amazon here.


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