Evaluating the Impact of Intralipid Infusion on Pregnancy Outcomes in Infertility Treatments: A Retrospective Study

Background: Infertility is a multifactorial condition that causes significant emotional distress and financial burden for couples. Despite advances in assisted reproductive technologies (ART), many patients experience recurrent implantation failure (RIF) or pregnancy loss. Intralipid, an intravenous lipid emulsion, has been proposed as an adjunctive therapy due to its immune-modulatory effects, particularly in reducing elevated natural killer (NK) cell activity, which maybe associated with poor reproductive outcomes. This study evaluated the effect of Intralipid infusion on pregnancy rates and miscarriage rates in women with recurrent implantation failure undergoing in-vitro-fertilisation (IVF). Materials and Methods: This was a retrospective study of women who had suffered from recurrent implantation failure and underwent IVF between September 2023 and September 2024. A comparative group who did not have recurrent implantation failure matched for age were selected. Outcomes were clinical pregnancy and miscarriage rates. Results: A total of 113 women undergoing IVF were identified - 51 received intralipid. Intralipid was initiated at varying stages of the IVF process - a day before embryo transfer (ET) (18 or 35.3%), on the day of ET (20 or 39.2%) and after ET (13 or 25.5%). The clinical pregnancy rate was 44.2% in the treatment group compared to 29% in the comparator group (P< 0.05) while the miscarriage rates were 13.7% versus 11.3% (P>0.05). Elevated NK cells were present in 65.4% of the patients who received Intralipid, but the correlation between NK cell levels and pregnancy outcomes was weak (Spearman ρ = 0.032). No adverse effects were reported in any of the women. Conclusion Intralipid infusion increased the successful pregnancy rates in women who had had recurrent implantation failure at IVF. The clinical pregnancy rate was significantly higher than in who undergoing ART who had not suffered from RIF. These findings support several studies on the potential benefit and safety of intralipids in women undergoing ART but the numbers remain small and more prospective studies are needed to confirm these findings.