P-158 Effect of women body mass index on in vitro embryos development and effectiveness of «Assisted reproductive technologies»
Authors: Yakhyarova M , Zapiyeva D , Kim A , Zastavskiy I , Kudrina N 
Published: June 2023

Abstract

Study question
Does a woman's body mass index (BMI) affect the development of an embryo in vitro?

Summary answer
Evaluation of the development of embryos indicates that the overweight affects the development of the embryo and associated with a lower rate of live births.

What is known already
Excess weight and obesity - as a cause of infertility, occures against the background of existing metabolic disorders. Severe thinness and, like obesity, often lead to violations of the interval and reproductive functions of a woman. An increase in adipose tissue of more than 20% or more leads to dysfunction of the hypothalamic-pituitary-ovarian system. With obesity and emaciation of the body, a woman has various forms of menstrual disorders, the frequency of uterine bleeding and also endometrial pathology increases.

Study design, size, duration
This study included the retrospective analysis of Assisted Reproductive Technologies (ART) cycles using statistical data on the development of embryos in the Embryological laboratory, pregnancy and childbirth was carried out from 2016 to 2018. Morphological studies were carried out using Time-Lapse embryo imaging.

Participants/materials, setting, methods
In this study, morphological and biostatistical methods were used. The cohort of patients aged 20 to 45 years was divided into four groups: 1623 embryos from 243 underweight women; 19542 embryos from 2270 normal weight women (control group); 9701 embryos from 1069 overweight women; and 2668 embryos from 343 obese women.

Main results and the role of chance
In the group of underweight women the pregnancy rate is 46%, which is 3% less than in overweight and obese group of women, while the percentage of the control group is 47.5%. However, the results of live births in group of women with obesity is 7% less than in women of normal weight, which is 29 and 36 percent respectively. In addition, a comparative analysis of the number of fertilized eggs showed that at a normal BMI, 6.3 ± 0.4 oocytes were fertilized, while in the group of women with second-degree obesity only 4.2 ± 0.3 oocytes. Based on the results of the T-test, it can be concluded that these indicators have differences with a significance level of less than 0.05. Also, the results obtained indicate differences in the maturity of embryos at the blastocyst stage, where blastocysts of excellent quality matured in the control group of 3.4 ± 0.4 embryos, and in the experimental group with obese women 2.4 ± 0.1 embryos. Furthermore, the frequency of live births showed a relationship between the norm and high BMI. In the control group, the result was 0.7 ± 0.02, while in first-degree obesity, the result was 0.2 ± 0.06.

Limitations, reasons for caution
The main limitation of this study is a verity of women with different anamnesis, which were not taken into account. The grading of blastocysts is subjected to a human factor. The limitation of the Time-lapse technology is the inability to rotate the embryos making it very difficult to observe.

Wider implications of the findings
This method needs further investigations about limitations, such as the age of patients, type and heaviness of infertility, existing diseases and previous pregnancies in anamnesis.

Trial registration number
Not Applicable