The only research studies currently available relate to mouse data from 1994, a small trial in humans also in 1994 which was for women with recurrent miscarriage not implantation failure (the trial was too small to see a benefit), and a few recent trials that show that you can suppress the levels of Natural Killer (NK) cells by giving it to women with elevated NK cells (tested because of either recurrent miscarriage or recurrent implantation failure), and how long that effect lasts for. But they didn’t look at pregnancy rates as a consequence of treatment.
Interpretation of the available information is as follows:
Intralipid might be useful in women with elevated NK cells but we don’t know if that translates to improved pregnancy or live birth rates. It is important to test both peripheral (blood) NK cells and uterine NK cells as they can be different (ie just because the blood is normal doesn’t completely rule out the possibility that they are raised in the uterus). Both plaquenil (some use it for treatment of SLE) and prednisone suppress NK cells. The suggested usual treatment for someone with high NK cells is prednisone 10 mg until the trigger and 20 mgs until the outcome of the cycle is known and clexane daily.
Natural Killer Cells, if a patient has more than 10 cells per high powered field then they have more than is normal and this may be a deterrent to achieving a pregnancy and can lead to recurrent miscarriage.
The treatment then is to be on either Prednisolone 20mg a day or Dexamethasone 1mg a day from the first day of your cycle.
Additional the patient can receive an infusion of 20% Intralipid given over 3 hours, 7-14 days before the embryo transfer or 1 week before anticipated insemination in an intrauterine insemination cycle. If serum pregnancy tests positive the Intralipid then needs to be repeated within a week of the result.
Refer to Intralipid Consumer Information Leaflet for more information