P-074 The effect of sperm from male patients who use electronic cigarettes on the euploidy ratio of embryos during in vitro fertilization procedures
Authors: Lee J , Shin S  H , Kim G  W , Kim H  Y , Cha H  J , Ju H , Kim H  K , Choi J  Y , Kim T  J , Han S , Choi W 
Published: July 2024

Abstract

Study question
What is the effect of electronic cigarettes as a substitute for regular cigarettes on sperm and subsequent embryo development in IVF patients?

Summary answer
E-cigarettes are just as harmful to male fertility as regular cigarettes, reduce the euploidy rate of the embryo, and have negative effects on pregnancy.

What is known already
Many harmful substances from smoking are known to negatively affect sperm development and function. It causes high elevations in sperm DNA fragmentation (SDF), which are associated with embryo euploidy rates. Recently, the use of e-cigarettes is increasing as an alternative to regular cigarettes because they are less harmful and safer. However, several animal studies have shown that e-cigarettes are just as harmful as regular cigarettes and can have negative effects on sperm and fertility. Preliminary data showed that SDF increased with e-cigarettes compared to regular cigarettes. Therefore, we would like to find out whether e-cigarettes affect embryo euploidy.

Study design, size, duration
In this study, from January 2022 to December 2023, 1,725 cycles of PGT-A (PGT for aneuploidy) were analyzed among the patients of IVF. The average ages of men and women were 40.0±4.6 and 38.7±4.0. A total of 4,796 embryos were analyzed (2.8 ± 2.0 per case) for euploidy rates.

Participants/materials, setting, methods
Blastocyst biopsy and PGT-A were performed, and embryo euploidy rates was confirmed. In male, the number of no smoking IVF cycles was 1061 and the number of embryo biopsies was 2.9 ± 2.1. The number of IVF cycles using regular cigarettes is 370, and the number of embryo biopsies is 2.8 ± 2.1. The number of IVF cycles using e-cigarettes was 294, and the number of embryo biopsies was 2.5 ± 1.6.

Main results and the role of chance
Based on the total female age, the embryo euploidy rate was nonsmoking (27.3%), regular cigarettes (23.6%), and e-cigarettes (18.8%). Among women under 38 years of age, e-cigarettes (29.9%) had a lower euploidy rate than regular cigarettes (37.4%), and nonsmoking (38.2%) had the highest rate. Among women over 38, the euploidy rate dropped significantly compared to those under 38, including nonsmoking (18.9%), but it was also lower for e-cigarettes (11.6%) than regular cigarettes (17.7%). Based on female age under 38 years old, the embryo euploidy rate among male age under 39 years old was nonsmoking (39.0%), regular cigarettes (38.3%), and e-cigarettes (31.7%). And among men over 40, the group with the lowest embryo euploidy rate was those who used e-cigarettes (no smoking (35.0%), regular cigarettes (32.6%), e-cigarettes (27.7%)). Based on the age of women over 38 years old, the euploidy rate among men under 39 years of age is nonsmoking (23.9%), regular cigarettes (21.6%), and e-cigarettes (12.7%). And the euploidy rate among men over 40 years of age is nonsmoking (16.8%), regular cigarettes (16.5%), and e-cigarettes (11.8%). nonsmoking is essential to maintain a high euploidy rate in embryos, and e-cigarettes may have a more adverse effect on pregnancy than regular cigarettes.

Limitations, reasons for caution
Because there are various types of e-cigarettes, it is expected that the degree of harmfulness will vary, but the number of patients was not sufficient to conduct research on each type of e-cigarette. Therefore, it is believed that the above problems should be solved through additional research.

Wider implications of the findings
This study is a study that links the harmful effects of cigarettes and the polyploidy of embryos. Electronic cigarettes, used as an alternative to regular cigarettes, may reduce embryo euploid production and cause recurrent pregnancy failure. Therefore, it is believed that electronic cigarettes should also be managed appropriately.

Trial registration number
not applicable