The Effect of Over Weight on Oocytes Quality in IVF Patients

The effect of obesity on female fertility has been extensively tested. Obese women have increased time to pregnancy and remain subfertile even in the absence of ovulatory dysfunction. They present with higher incidence of infertility compared to normal weight women. Furthermore, obesity affects the outcome of fertility treatments, resulting in decreased ovarian response to stimulation, lower quantity and quality of oocytes, and adverse effects on the quality of embryos including lower blastocyst formation and on the chances of conception.

Subfertility and infertility research are aiming to find different markers that may shed light about oocyte quality. It is known that follicular fluid is the microenvironment of the oocyte. Both cumulus cells (CCs) and follicular fluid (FF) are critical determinants for oocyte and reflect its quality.

The oocyte in the ovary develops with the support of cumulus and granulosa cells, which are in close contact with her by gap junction. The oocytes are known to be unable to synthesize their own cholesterol and have very poor glucose metabolism to produce energy. The oocytes are supported for this purpose by cumulus and granulosa cells, and they basically reflect the quality of the oocytes. Evaluating different markers in the follicular fluid and cumulus cells including mitochondrial-DNA and protein that are known to be biomarkers of quality may help us to understand the impact of obesity on oocyte quality without harming the valuable resource.

In this study, the investigators aimed to evaluate the impact of obesity on oocyte quality using 2 main factors reflecting oocyte quality mtDNA levels in CCs and levels of proteins BMP-15 and HSPG2 in FFs.

Women younger than age 41 years, undergoing IVF/IVF-ICSI cycles, participated in the study. Patients were allocated into two BMI groups (<25 and >30) based on WHO criteria to evaluate distinctly different groups. The attending physician determined each patient's care plan without any relation to study recruitment. At the time of ultrasound-guided transvaginal ovum pick-up (OPU), only patients with four or more follicles were recruited. Demographic information was recorded from the electronic medical records, including demographics and obstetrical history (age, parity, BMI, number of previous pregnancies and abortions, prior IVF/ICSI cycles, and biochemical and basal hormonal profile), cycle characteristics (the stimulation protocol, endometrial thickness, and E2, LH and progesterone levels on hCG administration day), cycle outcomes (fertilization rate, number of oocytes, transferred and frozen embryos) and treatment outcomes (chemical and clinical pregnancy rate). Women who had undergone fertility preservation or had comorbidities, such as endocrine disorders, cancer, or other chronic diseases, were excluded.