Junmei Fan,1,* Jinghui Zhao,2,* Junkun Zhang,3 Yanhua Chen,1 Xingyu Bi,1 Huiping Liu,1 Junfen Liu,1 Jinbao Wang,1 Xueqing Wu1 

1Department of Reproductive Medicine Center, Children’s Hospital of Shanxi and Women Health Center of Shanxi, Taiyuan, Shanxi, 030013, People’s Republic of China; 2Department of Pediatric and Adolescent Gynecology, Shenzhen Children’s Hospital, Shenzhen, Guangdong, 518000, People’s Republic of China; 3Department of Intensive Care Unit, Shanxi Bethune Hospital, The Third Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030000, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Xueqing Wu, Department of Reproductive Medicine Center, Children’s Hospital of Shanxi and Women Health Center of Shanxi, 13th Xinmin North Street, Xinghualing District, Taiyuan, Shanxi, 030013, People’s Republic of China, Tel +86 351 3360725, Email xueqingw_wu95@163.com

Background: This study aimed to explore the effect of vitamin D supplementation on lymphocyte subsets in infertile women.
Methods: The study involved a total of 247 patients who suffered recurrent embryo implantation failure (RIF) or recurrent spontaneous abortion (RSA) between January and December 2019 in the Reproductive Medicine Center of Children’s Hospital of Shanxi and Women Health Center of Shanxi. The differences in the vitamin D and lymphocyte subsets of the two diseases, the correlation between the 25-hydroxy vitamin D and lymphocyte subsets, the changes in the lymphocyte subsets after vitamin D supplementation and the impact on pregnancy outcome were analysed.
Results: The prevalence of vitamin D deficiency was 77.33% (191/247). After vitamin D supplementation, there were no significant differences in helper T cells (Th), cytotoxic T cells (Tc), Th/Tc and natural killer cells (NK) (p > 0.05), but there were significant differences in leukocyte differentiation antigens 3+ (CD3+), natural killer T cells (NKT), B lymphocytes and vitamin D (p < 0.05). Before vitamin D supplementation, the difference in the composition ratio of different vitamin D levels between the RIF and RSA groups was not statistically significant. At different vitamin D levels, there were no significant differences in CD3+, Th, Tc, Th/Tc, NK or B lymphocyte (p > 0.05), but there was a significant difference in NKT (p < 0.05).
Conclusion: Vitamin D supplementation can reduce the level of NKT in infertile women, which may be of benefit to the pregnancy outcome of couples who experience RIF.

Keywords: recurrent embryo implantation failure, infertility, lymphocyte subsets, recurrent spontaneous abortion, vitamin D