P-273 Oocyte competence is affected by Body Mass Index in women undergoing in vitro fertilization procedures
Authors: Sanchez Pavon A , Mendoza H , Valdivieso P , Zambrano M , Garcia-Ferreyra J 
Published: June 2022

Study question

Is body mass index (BMI) an important factor that affects oocyte competence in patients subjected to in vitro fertilization procedures?

Summary answer

High BMI affects oocyte competence, causing abnormal blastocyst development, and reduced clinical outcomes. Overweight and obesity women needed more oocytes to obtain a gestational sac.

What is known already

Overweight and obesity are systemic and tissue-specific conditions that lead to chronic inflammation and oxidative stress to produce an unregulated and persistent secretion of chemokines and cytokines, which are released into circulation inducing inflammatory responses in several tissues, including the ovaries. Cytokines, chemokines and adipokines play essential roles in steroidogenesis, follicular growth, cumulus expansion, and ovulation; however, alterations in their patterns of synthesis and secretion impair meiotic and cytoplasmic maturation of the oocyte, reducing its developmental competence for fertilization and pre-implantation development. Overweight or obese women had significantly lower clinical pregnancy and live birth rates and significantly higher miscarriage rates.

Study design, size, duration

The following work is a retrospective nonrandomized study that included a total of 1839 oocytes obtained from 201 IVF/ICSI non-donor cycles performed between January 2018 and December 2019.

Participants/materials, setting, methods

The oocytes were allocated according to BMI of patients in three groups: Normal group: 18.5-24.9 ( n =  608 oocytes), overweight group: 25.0-29.9 ( n =  832 oocytes) and obese group: ≥30.0 ( n =  399 oocytes). Extended embryo culture until blastocyst stage was done in all patients. Fertilization, development of blastocyst, transferred embryos, pregnancy and implantation rates were compared between groups. Number of oocytes needed to obtain a gestational sac (oocyte competence) were analyzed and compared by group.

Main results and the role of chance

Fertilization rates (87.7%, 85.3%, and 84.0%), and transferred embryos (1.84, 1.84, and 1.86) were similar between three evaluated groups. Blastocyst development rate (48.2%, 40.0%, and 40.1%), pregnancy rate (67.2%, 41.9%, and 39.5%), and implantation rate (53.7%, 31.8%, and 28.2%) were significantly reduced in women with overweight and obesity compared to women with normal weight ( P &lt;  0.05). To obtain a gestational sac, 2.1 and 1.8 more oocytes were needed by obese and overweight women, respectively, than the control group, suggesting oocyte competence is negatively affected by higher BMI.

Limitations, reasons for caution

The retrospective nature of this study and the small sample size may be reasons for caution.

Wider implications of the findings

The findings in this study suggest that a weight above normal will progressively decrease oocyte competence thus, it is necessary to have a greater number of oocytes in patients with overweigh and obesity to have a gestational sac when compared with patients of normal weight.

Trial registration number

non applicable