Kamath 2015.

Study characteristics
Methods	Study design: RCT Setting: university level infertility centre in India Period: The duration of the study was 3 years (from September 2011 to June 2014)
Participants	Eligible 72 women, 12 declined to participate Inclusion criteria: all consecutive women who were due for a fresh blastocyst transfer and had supernumerary embryos available for cryopreservation, patients with previously unsuccessful fresh blastocyst transfers and those who did not undergo fresh transfer due to high risk of OHSS, women who had a successful outcome previously and were interested in having another child. 60 women undergoing vitrified warmed blastocyst transfers, were randomised to SEET (n = 30) or control (n = 30) Baseline characteristics: Study group (n = 30) Age (Years) 29.9 (4.0) Body Mass Index (kg/m2) 24.51 (3.36) Duration of infertility (years) 7.55 (3.36) Total dose of gonadotrophins (IU) 1914.17 (900.35) Estradiol levels on trigger day (pg/ml) 3282.42 (2154.68 Number of MII oocytes 13.05 (5.34) Number of fertilised oocytes 10.59 (4.38) Number of blastocysts transferred 2.1 (0.5) Number of good quality blastocysts transferred (≥ 3AA) 1.8 (0.5) Control group (n = 30) Age (Years) 29.8 (4.3) Body Mass Index (kg/m2) 24.49 (3.26) Duration of infertility (years) 8.58 (3.62) Total dose of gonadotrophins (IU) 1792.50 (764.52) Estradiol levels on trigger day (pg/ml) 2737.62 (1353.83) Number of MII oocytes 13.53 (5.22) Number of fertilised oocytes 10.28 (3.64) Number of blastocysts transferred 1.9 (0.6) Number of good quality blastocysts transferred (≥ 3AA) 1.7 (0.6) Type of infertility Primary 14 Secondary 16 Previous ART attempt Yes 13 No 17 ART protocol Antagonist 13 Long protocol 17 Ultralong protocol 0 Type of infertility Primary 19 Secondary 11 Previous ART attempt Yes 9 No 21 ART protocol Antagonist 10 Long protocol 16 Ultralong protocol 4
Interventions	Uterine flushing with supernatant embryo culture medium in vitrified warmed blastocyst transfer cycles compared to direct transfer In women allocated to the SEET group thawed supernatant embryo culture medium was injected into the uterine cavity transcervically two days prior to the planned blastocyst transfer. In the control group, direct vitrified warmed blastocyst transfer was performed.
Outcomes	Main outcome measure(s): Positive (βhCG‐ biochemical) pregnancy rate per embryo transfer (primary) Clinical pregnancy rate per embryo transfer (singleton‐ twins‐ triplet) Implantation rate per embryo Multiple pregnancy rate per clinical pregnancy Miscarriage rate per clinical pregnancy Live birth rate per embryo transfer
Notes	Study funding: Research Grant, Christian Medical College, Vellore. Conflict of interest None to declare. Authorship role KG and MSK conceived and designed the study. MM and MSK analysed and interpreted the data. MM, MSK and KG wrote the manuscript. KB, NNV, AJ, MM, MK and MSK contributed to data collection and/or performed procedures. All the authors contributed to write the manuscript. All the authors approved the final version of the manuscript.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Women entering the trial were randomly distributed, using a computer generated randomisation sequence (blocks of 6) into two groups The randomisation sequence was generated by a statistician from the institutional biostatistics department
Allocation concealment (selection bias)	Low risk	Allocation concealment was achieved by using consecutively numbered opaque sealed envelope. Once the women were planned for vitrified thawed transfer, the envelope was opened
Blinding of participants and personnel (performance bias) All outcomes	High risk	Authors report the lack of blinding as one of the limitations of the study
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information provided to reach a conclusion
Incomplete outcome data (attrition bias) All outcomes	Low risk	There were no drop outs in the trial, as reported by authors All women who entered the trial were available for analysis with no loss to follow up reported (30 in each group)
Selective reporting (reporting bias)	Low risk	Adverse events reported ‐ expected outcomes analysed‐ published protocol (CTRI/2013/01/003280)
Other bias	Low risk	The study was registered ‐ methodological rationale ‐ distribution of tasks The study was approved by the institutional review board. The trial was registered with the clinical trial registry of India (CTRI/2013/01/003280) The small sample size was based and adequately powered to detect differences on the clinical pregnancy rate