Natural Killer Cells
3 Replies
Alison - February 6


I wondered if you could help me.

I have had my 3rd IVF and am now 21 weeks pregnant. I have been treated with 3 IVIG's and after my last blood test was told that my levels are ok and that I do not need any other tests or IVIGs.

I am still on Heparin and asprin which my Consultant at the IVF Clinic has told me to continue till week 28 when they will review it again.

However my Midwife refferd me as standard practice to a local Consultant. This consultant has recommended that I stop the heparin based on the fact that she feels there is no medical benefit for me to continue this. She said it has no effect on the baby as it is going into my blood.

The IVF Consultant has said that if I want to stop I can if my other Consultant has recommended it. When I asked the nurse at the IVF Clinic what the heparin was doing she said it was helping my baby to grow and helping reduce my killer cells levels. However previously I was told I don't need any more tests for the NK Cells and I feel they are contradicting themselves.

My problem is I just don't know what to do. I just want to know if there is any risk to my baby if I either continue or stop the heparin and no-one seems able to tell me.

I would rather stop the heparin as I really don't want to continue putting drugs into my body if I don't need to, But on the other hand after everything I have gone through I do not want to risk anything happening to my baby.

Can you answer what the heparin is doing for my baby and would there be any risk to me stopping the heparin?

Thanks very much, I will look forward to your response.


Dr Smith - February 6

The IVIg was to supress the abnormal activation of the NK cells. After the first trimester, IVIg is usually discontinued.

Heparin prevents very small clots (microclots) from blocking the placental blood vessels that bring nurishment to the growing baby. Heparing has no effect on NK cells. I'm not sure whether of not you have, in addition to the immunological problem, a clotting problem. Ask your doctor. If you also have a clotting problem, the Heparin may continue to be necessary through the pregnancy. If no clotting problem has been identified, you may be able to stop the Heparin.


Alison - February 7

Thanks for your response. My local Consultant has told me I have no clotting problems or any history or family history of it which is one of the reasons why she can't really understand why I am still on it.

I spoke to the Dr at the IVF Clinic and he told me he did not think there would be harm to my baby if I did stop the heparin and that they always continue the heparin until week 28 for people who have had high levels of NK cells as a prophylactic measure.

However if the heparin has no effect on the NK Cells then I can't really see any point in continuing with it.

I know its my decison and I am worried about it but based on what you have said and what the other Consultant said I will probably stop. Do you think that will be ok? I know no-one can make the decision but based on your experience would you say there is no reason for me to be on the Heparin anymore?

Thanks very much


Dr Smith - February 8

I'm going to beg off on your question. I'm not a physician, so I cannot advise to stop or continue a particular perscribed medical treatment. Sorry, but I would be crossing a legal line and could leave myself open to litigation (practicing medicine without a license).



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