A. Study published only as an abstract. Insufficient details regarding randomization, allocation concealment, missing outcome data, Measurement of the outcome and selection of the reported outcome.
B. When analyzing the reported results for clinical pregnancy (137/193 vs. 124/193), we observed that the reported difference was not statistically significant p =0.19), but authors have claimed that it was significant (p<0.05), suggesting bias of the study group favoring the intervention.
C. Randomization was achieved by the embryologist according to a computer-generated randomization table a day before the embryo transfer. Both the clinician performing the embryo transfer and the patient were blinded for the allocation. Institutional review board approval was not obtained. Consecutive embryo transfer cycles (not participants) were randomized, allowing the same person to enter more than once in the study.
D. ET cycles (not participants) were randomized, allowing the same person to enter more than once in the study. Additionally, there is a substantial difference between the group size (N=155 in the study group and N=215 in the control group).
E. All patients meeting the study criteria were included after obtaining their consent. No patient refused to participate in the study. All patients included in the study proceeded to the stage of embryo transfer. Randomization to study or control group was performed on the day of embryo transfer based on a computer originated random number sequence, no details regarding allocation concealment. Outcomes were not defined.
F. Nondonor patients were randomized from a computer-generated random number sequence using sealed envelopes to either a treatment (ET with EmbryoGlue) or a control (ET with standard culture media) group. Clinical pregnancy was defined as at least one intrauterine gestational sac on ultrasound exam 2 weeks after positive beta hCG. A pregnancy was considered to be ongoing if fetal cardiac activity was present at 7 weeks of gestation. Data from live birth was obtained from the previously published review (Heymann et al., 2022), but the results were close (49/117 vs. 39/108) to that reported for ongoing pregnancy (52/117 vs. 41/108). The study was not previously registered, and we did not find a published protocol. It is also not clear in the report whether the participants have signed informed consent.
G. The randomization to the study and control groups was performed using a computerized randomization table; however, there is no information regarding allocation concealment. It is not clear whether women were allowed to participate more than once in the study. Additionally, the proportion of women with previous implantation failure was larger in the control group (11/28=39% vs. 20/37=54%). The study was not previously registered, and we did not find a published protocol. It is also not clear in the report whether the participants have signed informed consent. Authors only presented “pregnancy rate” in their report; data for quantitative analysis were extracted from a previously published systematic review .
H. No information regarding randomization and allocation concealment. It is not clear whether women were allowed to participate more than once in the study. The study was not previously registered and we did not find a published protocol. It is also not clear in the report whether the participants have signed informed consent. I. We identified only the registration in ClinicalTrials.gov. Study was terminated prematurely because the implantation rate was significantly lower in the treatment group using HA-Enriched medium for embryo transfer (https://clinicaltrials.gov/study/NCT00588250). No results were published online and we did not identify the final publication. Data for quantitative analysis were extracted from a previously published systematic review.
J. Some problems in their second randomization (Sellers et al., 2022). No entire number would result in the reported proportions and the number of clinical pregnancies is lower than the number of live birth and miscarriages. We tried contact with the authors by several different emails, but we did not have any response. K. No information regarding randomization and allocation concealment. It is not clear whether women were allowed to participate more than once in the study. The study was not previously registered and we did not find a published protocol.
L. As reported by the authors, “The study was conducted between June 2006 and June 2007. The last patient was recruited in February 2007.” However, the study was submitted to publication in Jan.29.2007. Patients were randomized according to a previously prepared computer- generated randomization list. Randomization was stratified for day 3 and day 5 transfers. The allocation was disclosed by the nurse coordinator to the chief embryologist who was loading the catheter, after the opening of consecutively numbered sealed opaque envelopes on the morning of the embryo transfer. The study group is the same of another included study (Balaban et al., 2004) where the authors reported a significant difference following an intervention that is not compatible with the reported numbers.
M. Preliminary publication of a study (N=98) that planned to include a total of 250 women, but we did not identify the publication of the completed study.
N. The study group is the same of another included study (Balaban et al., 2004) where the authors reported a significant difference following an intervention that is not compatible with the reported numbers.
O. Trial Registration=NCT02725827, performed in two centers. One day before FET, the women were randomly assigned to either the HA group or the control group according to a computer-generated randomization list with a 1:1 ratio and a block size of 10. The randomization list was prepared by a designated research nurse who was not involved in patient care. The assignments were kept in sealed opaque envelopes, which were opened by the embryologist 1 day before FET to prepare the transfer medium. The embryologist was not otherwise involved in patient care. The women and the clinicians and nurses involved in recruitment, preparation, embryo transfer, and subsequent follow-up were all blinded to group assignments.