OBJECTIVE: To evaluate the association between serum levels of fatty acids, as biomarkers of fatty acid intake and metabolism, and treatment outcome among women undergoing IVF.

DESIGN: Nested case-control study among women undergoing IVF treatment in three fertility centers in the Boston area.

MATERIALS AND METHODS: Pre-treatment levels of serum fatty acids were measured in 100 women using gas chromatography, expressed as the percentage of total fatty acids and grouped into low, intermediate and high levels of specific fatty acids. Logistic regression was used to estimate the odds ratio (95% confidence interval) of implantation failure and live birth for women in the intermediate and high serum fatty acid levels in relation to women in the lowest levels. Models were adjusted for age, body mass index, treatment protocol, peak E2 level, study year and study center.

RESULTS: There was an inverse relation between pre-treatment serum levels of trans fatty acids and live birth rate. The association was strongest for serum levels of 18:2 trans fats. Compared to women in the lowest third of serum 18:2 trans fats, women in the middle third had 90% (95% CI: 57% - 98%) and women in the highest third had 82% (24% - 96%) lower odds of live birth per initiated cycle after accounting for potential confounders (p, trend = 0.02). The lower birth rate appeared to be due in part to a greater frequency of implantation failure. Compared to women of the lowest third of 18:2 trans fats women in the highest third had a 3.6-fold (-1 – 13) greater odds of implantation failure per initiated cycle and a 6.7-fold (1.5 – 30) greater odds of implantation failure per embryo transfer. Serum levels of saturated, mono-unsaturated or poly-unsaturated fatty acids were unrelated to the live birth rate.

CONCLUSION: Pre-treatment serum levels of 18:2 trans fatty acids, a biomarker of intake, are associated with a greater implantation failure rate and lower live birth rate among women undergoing IVF.