Comparison of pregnancy outcome in intrauterine insemination-candidate women with and without endometrial scratch injury: An RCT

Abstract Background Endometrial scratch injury is considered controversial in increasing the success rate of assisted reproductive technology. Objective To compare the pregnancy outcomes in women undergoing intrauterine insemination with and without an endometrial scratch. Materials and Methods In this randomized clinical trial, 150 women referred to the Fatemieh Hospital, Hamadan, Iran who were candidates for IUI between December 2017 and December 2018 were randomly assigned into two groups (n = 75/each) with or without an endometrial scratch (as case and control groups, respectively). Women in both groups were in proper and identical protocol for IUI. Chemical and clinical pregnancies, abortion, and live birth rate, also pregnancy complications were compared between the groups. Results Chemical and clinical pregnancy rates were higher in the case than the control group (p = 0.25, p = 0.54, respectively). In the case group, the abortion and multiple gestation rates were 14.3% and 4.3%, respectively, while it was 5% in the control group (p = 0.60, p = 0.54 respectively). The endometrium thickness on day 21 was higher in the case group than the control (p = 0.01). Conclusion Endometrial scratching in intrauterine insemination women is not associated with an increase in both clinical and clinical pregnancy rates, however, studies with a larger sample size are recommended to evaluate this intervention.


Introduction
Intrauterine insemination (IUI) involves a variety of procedures, all done by placing whole or prepared sperm into the uterine cavity (1). The success rate of IUI depends on several factors, including IUI time, catheter type, ovulation induction method, inoculated semen volume, and inoculation (2). IUI can be used to normalize the ovulation cycle, but nowadays, ovulation stimulation cycles are used more often for infertility treatment because they make the timing of the procedure more accurate and the timing of ovulation more predictable (3).
Embryo implantation is one of the most important causes of the failure of assisted reproductive methods, including IUI (4). The IUI time is determined by considering the number and diameter of the follicles and the size of the endometrial thickness to obtain the best results. While some studies have shown that itching or intentional injury to the endometrium results in better outcomes, others have found no difference and have reported no beneficial results (5)(6)(7). Some studies that have found beneficial results of endometrial scratching are studies with small sample sizes that are not reliable (8,9).
A successful pregnancy requires good-quality oocyte and sperms that lead to a good-quality embryo and an endometrium that is ready for the embryo. Generally, days 19

Materials and Methods
Out of the 300 estimated sample size, 150 cases were removed due to lack of financial    A Chi-square test was used to compare the relationship between the qualitative variables and student's t test or non-parametric equivalent was used to compare the quantitative variables. P-value < 0.05 was considered as statistically significant.

Results
In this clinical trial study, 150 infertile women undergoing IUI who met our inclusion criteria were randomly assigned into two groups (n = 75/each). Figure 1 shows how patients were selected and followed-up. Both groups were compared in terms of the mean age, duration of infertility, body mass index, number of dominant follicles, type of infertility, cause of infertility, and history of IUI (Table I). The numbers, motility, and morphology of semen fluid prepared for intrauterine injection were compared in both groups (Table II).

Discussion
This clinical trial was performed to investigate the effect of endometrial scratching on women who were candidates for IUI on their pregnancy outcomes and its associated complications.
The findings of this study showed that endometrial scratching was associated with an 8% and 4% increase in chemical and clinical pregnancy rates, respectively, in the case group than in the control group, although this difference was not statistically significant but may be clinically significant (for patients and physicians).
However, the observed difference could be statistically significant if the sample size was higher. Endometrial thickness was associated with a significant increase in the case group, which may indicate a better efficacy of this case in these women. IUI is an inexpensive, noninvasive method that is widely used in treating infertile couples. This method, along with controlled ovarian hyperstimulation, is widely used to However, the success rate of IUI is estimated to be 10-25% (13). So, it is pertinent to work toward improving its success rate.
Some studies have shown that endometrial scratching is associated with increased rates of pregnancy such as normal saline infusion, curettage, and hysteroscopy (7,9,14 It is yet not clear why endometrial scratching is associated with increased pregnancy rates. One of the possible causes is the induction of decidualization (17) and increased secretion

Conclusion
According to the findings of the present study, endometrial scratching in IUI-candidate women is not associated with an increase in chemical and clinical pregnancy rates.
Further studies with larger sample sizes are recommended to confirm or reject this intervention.