Ladies - My RE replied to my request for the NK cells test with a lengthy response. And references of studies (1-3) to support his argument against the assays. He's definitely a doctor who strongly opposes the NKc test. I'll copy & paste the email in its entirety. Please leave feedback if you have any to contribute on an open discussion regarding this controversial test. TIA xx
Hi Angela:
Don’t waste your money on NKc assays.
The role that Natural Killer cells (NKc) play regarding infertility and miscarriage remains controversial. NKc are found in normal individuals with a healthy immune system and have specialized functions in the blood and endometrium (the inside lining of the uterus). Around the time an embryo implants in the endometrium, more NKc arrive to focus the establishment of a blood supply between the embryo and the uterus. Ultimately, only part of the uterus is attached to the placenta and NKc are believed to control this process. Without NKc the implantation process may proceed out of control, creating problems with the placenta and then problems with the pregnancy.
A theory has been recently proposed that too many NKc, or over-active NKc, can also cause problems with implantation by not allowing enough establishment of a blood supply between the embryo and the endometrium. A few small studies have found that women with too many, or over-active, NKc are more likely to have a miscarriage. However, larger studies found no link between NKc levels and miscarriage. The link between infertility and NKc is even more theoretical than the link between NKc and miscarriage. Neither has been proven with any reliable studies. Further, there is no consensus how to measure NKc, either.
Assuming there truly is a link between NKc and either infertility or miscarriage, the available treatments attempt suppress the overall immune system or involve blood thinners. The use of blood thinners, such as heparin, carries only a small risk to patients and heparin is relatively inexpensive. There are no studies proving its effectiveness for the treatment of high levels of NKc. Oral steroid pills, such as prednisone, Medrol (prednisolone) or dexamethasone, suppress the overall immune system and given for a short duration have few side effects and are inexpensive. Intravenous Intralipid therapy carries little risk but costs up to $700 per dose and typically 3 or 4 doses are recommended. One treatment, called Intravenous Immunoglobulin (IVIg) therapy is very expensive, unproven and may cause harm by injecting someone else's blood products into your own blood. As of July 2016, there are no studies showing that Intralipid or IVIg therapy enhances fertility or decreases miscarriage.1-3 Until there is better data, IVIg therapy or Intralipid therapy for NKc should be considered experimental, performed under surveillance with established research protocols and patients should not have to pay to participate in that type of experiment.
In summary, the link between NKc and fertility or miscarriage remains controversial. Until a true link exists, spending the money on the test does not make sense, particularly because it is not covered by insurance and there is no agreement how to test for NKc. On the other hand, I routinely recommend the oral steroid pills for many IVF patients, because the pills may help suppress factors in the immune system (not just NKc) when an embryo is implanting, are unlikely to cause any harm and are inexpensive.
1. Stephenson MD, Kutteh WH, Purkiss S, et. al. Intravenous immunoglobulin and idiopathic secondary recurrent miscarriage: a multicentered randomized placebo-controlled trial. Human Reproduction (2010) 25(9): 2203-2209.
2. Egerup P, Lindschou J, Gluud C, et. al. The effects of intravenous immunoglbulins in women with recurrent miscarriages: A systematic review of randomised trials with meta-analysis and trial sequential analysis including individual patient data. PLoS One (2015) 10(10):e0141588.
3. Christiansen OB, Larsen EC, Egerup P, et. al. Immunoglubulin treatment for secondary recurrent miscarriage: a randomised, bouble-blind, placebo-controlled trial. BJOG (2015) 122(4): 500-8.
Dr. ******
I'm am so curious about all your results. How long will it all take? Your hcg is dropping nicely, AF in no time!
How did you end up telling DH? I'm so excited for you after all the clinic/donor missteps, what a great outcome! 
It seems my nurse is out all week (in the past she's let me know that ahead of time...), so I've gotten no more details about the cycle. Ah, what's a little more waiting in the whole scheme of things... 
I love the opinions, though - always giving me/us things to think about.
