Oocytes of women who are obese or overweight have lower levels of n-3 polyunsaturated fatty acids compared with oocytes of women with normal weight.

Objective: To ascertain whether the oocytes of women who are obese or overweight have a different fatty acid (FA) profile than women with normal weight.

Design: Prospective case-control study.

Setting: Two IVF centers.

Patient(s): A total of 205 women undergoing IVF and intracytoplasmic sperm injection (ICSI) were included in the study, totaling 922 oocytes.

Intervention(s): The unfertilized and the immature oocytes from the women who underwent IVF/ICSI were subjected to FA analysis with capillary gas chromatography. Women were classified according their body mass index (BMI) as normal, overweight, or obese. Germinal vesicle oocytes, metaphase I oocytes, and unfertilized metaphase II oocytes were analyzed separately.

Main Outcome Measure(s): Fatty acid profile.

Result(s): A very different oocyte FA pattern was observed for each BMI. Women with normal weight had higher levels of saturated FAs, and lower levels of monosaturated FAs. Women who were obese had lower levels of n-3 polyunsaturated FA, and the lowest n-6:n-3 ratios. Regarding specific FAs, docosahexaenoic acid levels were lower in women with normal weight than in those who are overweight, and in women who are overweight than in those who are obese. The opposite occurred with eicosapentaenoic acid, with the highest levels in women who have normal weight followed by those who are overweight and lower levels in those women who were obese. When FA analysis was restricted to a subset of oocytes, many of these differences persisted.

Conclusion(s): Our study shows that oocytes from women who are obese or overweight have a different FA composition. This difference in levels could be related to the IVF poor outcome in these women. Therefore, this different composition could suggest that offspring of women who are obese or overweight have an unfavorable milieu even before conception.