Discussion on the Efficacy of Vascular Smooth Muscle Technology in the Treatment of Thin Endometrial Infertility

Objective: To clarify the efficacy of vascular smooth muscle technology in the treatment of thin endometrial infertility, and to provide a theoretical basis for the further diagnosis and treatment of thin endometrial infertility. Methods: In accordance with the inclusion and exclusion criteria, 2015.01-2020.01 selected thin endometrial infertility patients undergoing freeze-thaw embryo transfer at the Female Pelvic Floor Urinary Reconstructive Center in Dalian Municipal Women and Children’s Medical Center were selected according to different treatment methods. For the two groups, pure estrogen therapy was used as the control group, and vascular smooth muscle technology combined with estrogen therapy was used as the study group. All patients' endometrial thickness and pregnancy and delivery were recorded before and after treatment. Results: 1. The endometrial thickness of the study group was significantly larger than that of the control group after treatment, the difference was statistically significant ( P <0.05); 2. 80 patients in the study group, 13 cases of successful pregnancy and delivery, 5 cases of biochemical pregnancy; the endometrial changes of the 50 patients in the control group was not obvious after treatment, none of the endometrial thicknesses reached the embryo transfer standard, and none were transplanted. Conclusion: Vascular smooth muscle technology can effectively increase the thickness of endometrium, with the aim of assisting to improve the pregnancy success rate of thin endometrial infertility through vascular smooth muscle technology.


Introduction
With the increase of infertility patients year by year, currently the widespread development of assisted reproductive technology has successfully treated some infertility patients, but for some infertility caused by thin endometrium, there is still no effective treatment. As one of the important factors affecting women's pregnancy rate, the thin endometrium is increasing year by year. The pathogenesis is not completely clear, it may be secondary or primary [1] . At present, the clinical treatment methods of thin endometrium are mainly drug treatment and surgical treatment. High-dose estrogen treatment is the most common clinically used drug treatment, but the therapeutic effect is still controversial, some patients still have no obvious curative effect, the treatment method showed a 3 lack of response [2] , and was eventually informed that there might be no fertility opportunities. Finding new and effective treatments is an urgent task for patients, family members and medical workers. In recent years, with the rapid development of electrophysiology rehabilitation science and technology, treatment methods using electrophysiology as the main intervention method have attracted everyone's attention. The purpose of this study is to explore the efficacy of pelvic floor rehabilitation technology based on vascular smooth muscle technology in the treatment of thin endometrial infertility, and to promote the development of pelvic floor rehabilitation technology, with a view to providing diagnosis and treatment of thin endometrial infertility reference. Center.The methods were divided into two groups, the conventional estrogen treatment method was used as the control group, and the vascular smooth muscle technology combined with estrogen treatment was used as the study group. All patients signed the informed consent.

Efficacy observation:
Compare the endometrial thickness of the two groups before and after treatment with the maximum follicular diameter ≥18mm (the day of human chorionic gonadotropin injection),and follow-up of pregnancy and delivery.
(1) Determination of endometrial thickness: Obtain the largest longitudinal section of the uterus, measure the maximum distance between the anterior wall of the uterus, the posterior wall of the uterine muscle layer and the endometrium, and take the average of three measurements.
(2) Follow-up of pregnancy and childbirth: Follow-up of biochemical pregnancy, clinical pregnancy and childbirth.

Statistical methods
Statistical analysis was performed using spss21.0 statistical software. Measurement data that conform to the normal distribution were expressed as mean ± standard deviation, and t test was used; X 2 test was used for count data. P <0.05 was considered statistically significant.

2.Endometrial thickness comparison:
(1) Comparison between groups: There was no significant difference in endometrial thickness between the two groups of patients before treatment (P> 0.05).
The endometrial thickness of the study group was significantly larger than that of the control group after treatment(P<0.05); (2) Comparison within the group: The endometrial thickness of the study group after treatment was significantly greater than that before treatment, and the difference was statistically significant (P<0.05); the comparison of endometrial thickness of patients in the control group before and after treatment(P> 0.05). (Table 1).

Discussion
In recent years, the number of infertility patients has increased year by year, and research on the etiology that affects women's pregnancy rate and corresponding treatment methods has become a hot issue. Successful embryo implantation must have two conditions: a well-developed embryo and a receptive endometrium, both of which are indispensable. In female infertility, thin endometrium is a more important factor. Kunicki [3] et al believe that about 1/3-2/3 of human embryos eventually fail to implant due to uterine receptivity abnormalities, and the thickness of the endometrium is an important indicator for evaluating receptivity. The diagnostic criteria for thin endometrium are still not clear. Some scholars believe that the thickness of the endometrium is 6 to 8mm. Most researchers tend to endometrial thickness ≤7mm [4] . Most scholars agree that thin endometrium refers to the day when human chorionic gonadotropin or luteal support is given in assisted reproduction technology.
The thickness of the endometrium measured under ultrasound is ≤7mm, which is infertility. One of the most common causes of women with asthma [5] . The successful development of assisted reproduction technology has successfully rescued many infertility patients, but some patients with thin endometrial infertility due to the thin thickness of the endometrium, a variety of treatment methods are ineffective, resulting in unacceptable embryo transfer. Because the pathogenesis is not completely clear, the etiology is complicated, and although there are many treatment methods, there is no one method that is universally applicable and the effect is accurate. Usually, the disease duration of this part of the thin endometrium patients who do not respond is as long as several years or even ten years. Try many treatments that can be implemented have ended in failure. Clinical diagnosis of the disease is usually performed by ultrasound and hysteroscopy. Treatments for this type of disease include a large number of estrogen, aspirin, chinese medicine and the latest stem cell treatment, granulocyte colony-stimulating factor and other treatment methods. However, the efficacy is still not satisfactory, and some patients are ineffective for the above treatment schemes, and they are at risk of losing their mothers [6,7] . Miwa [8] and others first pointed out the pathophysiology of thin endometrium: slow growth of glandular epithelium, high resistance to uterine arterial blood flow, vascular dysplasia, and reduced expression of vascular endothelial growth factor. In recent years, with the rapid development of electrophysiology rehabilitation science and technology, treatment methods using electrophysiology as the main intervention method have attracted everyone's attention. Pelvic floor rehabilitation technology has been widely used in gynecological diseases and reproductive endocrine diseases, and has achieved good results [9] .
In clinical practice, pelvic floor rehabilitation technology is a new type of physical therapy, which can Djobo [10] and others have found that low-frequency electrical stimulation biofeedback therapy for thin endometrium can significantly increase the thickness of the endometrium. The increase in pregnancy rate was not significant. Kunicki [2] stimulation can increase the thickness of endometrium in patients with thin endometrial infertility and increase the pregnancy rate. Our study found that the vascular smooth muscle technology combined with estrogen treatment significantly thickened the endometrium, and the endometrial changes did not change after estrogen treatment alone, obvious or almost no change; 13 cases of successful pregnancy and childbirth in the study group, 5 cases of biochemical pregnancy; 50 patients in the control group did not reach the embryo transfer standard due to endometrial thickness after treatment, neither of them were transplanted, and the pregnancy rate in the study group was obvious improve. The analysis may lead to the following three reasons: Firstly, the patients in the group were severely ill, and the endometrial conditions were extremely poor, the thin endometrial infertility patients included in this study were subjected to a variety of methods in reproductive center of our hospital, those who did not see any effect in treatment, the thinnest intimal thickness was only 2mm, and patients and their families even lost hope, due to the severe infertility, although the endometrium was thickened, the effect was not significant, and only 9 courses, the time is short; finally, the number of patients included in the study is small, and the sample size needs to be expanded for further research.

Conclusion
Vascular smooth muscle technology can effectively increase the thickness of endometrium, with the aim of assisting to improve the pregnancy success rate of thin endometrial infertility through vascular smooth muscle technology.

1.Ethical Approval and Consent to participate:
This article has been obtained ethical approval and consent to participate.

2.Consent for publication:
This article has been obtained consent for publication.

3.Availability of supporting data:
This article has been obtained availability of supporting data.

4.Competing interests:
No competing interests in this article.

5.Funding:
This funding of article was from DaLian Municipal Women and Children's Medical Center.Dalian Medical Science.

6.Authors' contributions:
Zhongmin Wang was responsible for designing and supervising projects. Caixia Sun was responsible for implementing projects, collating data, and writing article.

7.Acknowledgements:
Thanks for support from DaLian Municipal Women and Children's Medical Center.