Increasingly, physicians are recommending intralipid treatments to their patients with recurrent miscarriage and to those who have high levels of natural killer cells (NK cells) to increase the chances of embryo implantation and full term pregnancy. However, as this form of treatment is quite new there is some variance in how the treatment is applied. In vitro studies have demonstrated that intralipids can suppress natural killer (NK) cytotoxicity, other studies have shown an increase in IVF success rates when intralipds are used. Intralipids may be one of the simplest and most effective ways to enhance implantation and prevent miscarriage but how should these treatments best be used?

A study was designed to answer this question by assessing exactly how long the NK cell-suppressive effects of intralipids last. Fifty women, all of whom had abnormal NK cell activity, were treated with intralipid infusions and their NK cell activity was measured at various intervals.

The study showed that 78% of the women demonstrated adequate NKa cell suppression in the first week after the intralipid treatment. A further 22% of the women showed some NK cell suppression, but their levels remained above normal, these women received a second infusion 2-3 weeks later which normalized their NK cell levels the following week. Four women were selected to have extra treatments and received three intralipid infusions in a 2-week period. In between the second and third infusion their NK cells became normalized too.

The study found that in forty seven women (94%) the NK-cell-suppressive effects of intralipids lasted between 6 and 9 weeks, in two of the women the benefit lasted only 5 weeks, and for one woman the effect lasted for 4 weeks. The researchers concluded that:

"Intralipid is effective in suppressing in vivo abnormal NK-cell functional activity. The results suggest that Intralipid can be used successfully as a therapeutic option to modulate abnormal NK activity in women with reproductive failure."

Some physicians administer one or two intralipid treatments in the weeks prior to conception to reduce NK cells and then recommend monthly treatment thereafter until the threat of miscarriage is diminished. Testing for NK cell values is also be used to guide treatments.

This article is intended for informational purposes only and is NOT intended to diagnose, offer medical or nutritional treatment or replace medical or nutritional advice for which you should consult a suitably qualified physician or dietitian.

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Note: The infusion used in this study was an intravenous infusion of intralipid 20% (9 mg/mL total blood volume - corresponds to 2 mL of intralipid 20% diluted in 250 mL saline; or 18 mg/mL - corresponds to 4 mL of intralipid 20% diluted in 250 mL saline).

2. Am J Reprod Immunol. 2008 Sep;60(3):258-63. Duration of intralipid's suppressive effect on NK cell's functional activity. Roussey RG, Acacio B, NG SC Coulam CB