Title: Sequential embryo transfer combined with intrauterine perfusion improved pregnancy
outcomes in patients with recurrent implantation failure
Version: 7 Date: 25 Nov 2023
Reviewer's report:
The research content cannot draw research conclusions.
"Introduction"
1. In fact, uterine cavity perfusion is not a routine operation, and there is no difference among
the three groups. The purpose of conducting sequential transplantation studies in RIF patients
was not clearly analyzed.
2. In lines 46-48, "50% to 60% of fertility couples aborted IVF-ET treatment after repeated failed
attempts" is inconsistent with clinical practice. In fact, the pregnancy rate of IVF is 50-60%,
and the incidence of RIF is only about 10%. There are many reasons for IVF pregnancy failure.
Here, RIF is not summarized, but IVF is mainly discussed.
3. Because the definition of RIF is not very clear, it is necessary to summarize the diagnosis,
possible causes and treatment of RIF in Introduction, to explain why sequential transplantation
was studied in RIF.
"Study subjects"
4. In line 82-84, "# 3 oocytes retrieved" is inconsistent with the definition of RIF in reference 10.
"Controlled ovulation induction and embryo selection"
5. For embryo selection, fertilization, such as 2PN rate, is a very important indicator. In addition,
blastocyst formation rate and high-quality blastocyst rate are also important indicators for
embryo quality. Therefore, can the author add these indicators?
6. The retrieved oocytes, AMH (ng/ml) and AFC (n) in Table 1 was not normally distributed,
which may be caused by the small sample size.
In addition, these three indicators all reflect the ovarian reserve function. If their distributions
were not normally distributed, the speculation cannot be ruled out that the differences about the
pregnancy outcome are due to the differences in ovarian reserve. How How should the authors
reduce the speculation?
"Discussion"
7. RIF mainly refers to the problem of endometrial receptivity discussed when pregnancy cannot
be obtained after multiple transplants of high-quality embryos. As the author pointed out that
"perform a sequential transfer in the same cycle maximizes the changes of coordination between
embryo recognition and endothelial receptivity and improve implantation rates".
However, in 209-218, authors mainly discussed that patients with low ovarian reserve function
had lower blastocyst formation rate and embryo quality, which had a great impact on pregnancy
outcome. It was also pointed out that there was no significant difference in retrieved oocytes,
AMH (ng/ml), AFC (n) among the groups in this paper, the authors can increase the 2PN rate,
blastocyst formation rate and high-quality blastocyst rate and other indicators reflecting ovarian
reserve function. In addition, the author also discussed "the risk of embryo free transfers", which
is often seen in patients with low ovarian reserve function. These discussions were all about
“seeds” rather than “land”. There were not in-depth discussions on the content and mechanism
of this research.
8. In 227-231 lines, the repetition of sentence.
9. In 247-289 lines, intrauterine perfusion was discussed at great length. However, this section
did not differ among the three groups, and its effect on pregnancy outcome cannot be elucidated
by the present study, which also deviates from the content and purpose of the study.
10. In 290-295 lines, the limitations of this study are described, but the limitations of this paper
are many, such as: 1) inadequate sample size, 2) intrauterine perfusion is not a routine procedure
and is invasive, increasing the risk of infections and costs, and its impaction itself increases the
study bias.
11. Lack of rigor in conclusions