Medicine in the field of infertility is constantly evolving, which is good news for couples who are struggling to conceive. We know much more about the causes of infertility now than ever before, and thankfully we have quite a few options to treat infertility as well, such as IVF.

Natural Killer Cells (NK Cells) are starting to be diagnosed as a possible issue in infertility, which is giving some answers to women who previously had been told they had unexplained infertility.

I’ve always believed it’s better to get a diagnosis (even though it can initially be a bit depressing), because then you have something to focus your treatments on.

NK cells are a natural part of our immune system, but in some people there is an overabundance of these cells in the uterus. This may lead to the body attacking an embryo when it’s trying to implant because it thinks it’s a foreign item that needs to be destroyed. We currently don’t have enough evidence in reproductive medicine to be sure this is exactly what’s happening though.

Steroid treatment is the preferred Western medicine form of treatment for high NK cells leading to miscarriage, however at this stage the evidence for it’s use is not considered to be available. Steroids are often started during the cycle, and stopped if there’s no pregnancy, or continued for at least the first trimester if there’s a positive pregnancy result.

While steroid treatment is prescribed by a qualified doctor, as with all medicines, it comes with risks and side effects. Those risks can include reduced foetal development, meaning your baby may be small at full term. (Source)

Chinese herbs may be another possible method of treating NK cell related infertility, however more high quality studies would be advised. The herbs are traditionally designed to support a healthy pregnancy by improving ‘Qi’ and reducing ‘restless foetus syndrome’ which is traditional Chinese medicine terminology.

According to a review of the available studies for Chinese medicine to treat threatened miscarriage:

“The meta-analysis in limited randomized clinical trials did not support that Chinese medicines alone were more effective than Western medicines. But it showed that combined Chinese and Western medicines were more effective than Western medicines alone to prevent inevitable miscarriage and continue pregnancy after 28 weeks of gestation. Meta-analysis in other clinical trials indicated that Chinese medicines alone or Chinese medicines combined with Western medicines were more effective than Western medicines alone to treat threatened miscarriage in relieving the clinical signs, including vaginal bleeding, low back pain, and abdominal pains. The result confirmed the therapeutic effects of Chinese medicines alone and combined with other pharmaceuticals for threatened miscarriage.”

Ultimately this review determined the outcomes of the available studies to not show effectiveness, but this was possibly due to the inconsistencies of herbal treatment (meaning different formulas were given based on Chinese medicine diagnoses, without adequate control groups).

I was unable to find any recent studies on Chinese herbs for NK cells.


If you have been diagnosed with high NK cells potentially leading to your infertility, it is advisable to work closely with your health professionals for treatment.