Zhu 2010.

Study characteristics
Methods	Study design: RCT Setting: A reproductive medical centre. Period: The subjects were recruited and studied for a period of 6 months from January to June 2008.
Participants	Patients: 90 women enrolled out of 96 eligible ones, aged 23–39 years, with a period of infertility of 3–8 years, due to the following infertility factors: tubal (n 1⁄4 54), unexplained (n 1⁄4 3), male (n 1⁄4 22), endometriosis (n 1⁄4 9), other (n 1⁄4 2). Inclusion criterion; women undergoing IVF or ICSI treatment for the first time. Exclusion criteria: women who had prior IVF or ICSI treatment and those who underwent a natural cycle IVF and had no appropriate embryo for ET. study group (45) control group (45) Baseline characteristics: Study group (45) Age (y) 31.9 ± 3.9 Duration of infertility (y) 5.3 ± 2.3 Serum hormone LH (IU/L) 5.5 ± 3.6 FSH (IU/L) 5.2 ± 2.4 PRL(mg/L) 10.7 ± 4.6 E (pmol/L) 293 ± 49 T (nmol/L) 1.7 ± 0.4 Infertility factors, {n (%)} Tubal 29 (64.4) Unexplained 1 (2.2) Male 10 (22.2) Endometriosis 4 (8.9) Others 1 (2.2) Infertility, {n (%)} Primary 26 (57.8) Secondary 19 (42.2) Number of dominant follicles 11.2 ±5.4 Number of retrieved oocytes 7.9 ± 3.3 Oocyte retrieval rate 70.5 % Number of maturation oocytes 6.9 ± 2.4 Oocyte maturation rate 87.3 % Number of fertilized oocytes 6.2 ±1.6 IVF 6.2 ± 1.9 ICSI 6.3 ± 1.4 Fertilization rate 78.5 % IVF 76.9 % ICSI 80.7 % Number of cleavage 5.7 ± 1.5 Cleavage rate 72.2 % Endometrium thickness 9.8 ± 1.3 on HCG day (mm) Number of grade 1–2 embryo 2.8 ± 0.9 Rate of grade 1–2 embryo (%) 49.1 Number of transfer embryo 2.2 ± 0.4 Control group (45) Age (y) 32.7 ± 4.4 Duration of infertility (y) 4.9 ± 1.7 Serum hormone LH (IU/L) 5.8 ± 2.9 FSH (IU/L) 4.8 ± 2.1 PRL(mg/L) 11.4 ± 5.6 E (pmol/L) 301 ± 43 T (nmol/L) 2.0 ± 0.7 Infertility factors, {n (%)} Tubal 25 (55.6) Unexplained 2 (4.4) Male 12 (26.7) Endometriosis 5 (11.1) Others 1 (2.2) Infertility, {n (%)} Primary 31 (68.9) Secondary 14 (31.1) Number of dominant follicles 10.8±4.6 Number of retrieved oocytes 7.7 ± 2.9 Oocyte retrieval rate 71.3 % Number of maturation oocytes 6.7 ± 1.8 Oocyte maturation rate 87.0 % Number of fertilized oocytes 5.8 ±1.8 IVF 6.0 ± 1.6 ICSI 5.6 ± 1.9 Fertilization rate 75.3 % IVF 77.3 % ICSI 73.7 % Number of cleavage 5.5 ± 1.4 Cleavage rate 71.5 % Endometrium thickness 10.1 ± 1.5 on HCG day (mm) Number of grade 1–2 embryo 2.6 ± 0.7 Rate of grade 1–2 embryo (%) 47.3 Number of transfer embryo 2.3 ± 0.3
Interventions	Uterine cavity injection of day 2 embryo culture supernatant before day 3 embryo transfer
Outcomes	Main outcome measure(s): Embryo implantation rate Pregnancy rate (Clinical pregnancy / singleton‐ twins) Abortion rate
Notes	All of the aforementioned clinical and laboratory procedures were identical between the study group and the control group. In order to avoid a selection bias, we excluded the women who had prior IVF or ICSI treatment and those who underwent a natural cycle IVF. We selected only those who were experiencing IVF or ICSI treatment for the first time, for whom there was a steady pregnancy rate of 45%–50% in our reproductive centre. All of the baseline characteristics between the study group and the control group were also not statistically significant differences, and the results of both groups in oocyte maturation, fertilization,embryo cleavage, and grade were identical.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Authors report that both selection and enrolment for each subject was decided collectively by three physicians First, 90 random numbers generated by means of computer were randomly divided into the study group and the control group All subjects enrolled chronologically were arranged according to the sequence of random numbers. As a result, the 90 subjects were randomly divided into the study group and the control group
Allocation concealment (selection bias)	Low risk	The random allocation sequence was concealed in a closed and dark‐coloured envelope until the day of oocyte pick‐up Randomization occurred after patients agreed to participate in the study
Blinding of participants and personnel (performance bias) All outcomes	High risk	The study was not blinded, as reported by authors
Blinding of outcome assessment (detection bias) All outcomes	High risk	The IVF or ICSI procedures were performed by the same physicians and laboratory technicians The treating sequence of the subjects was the same as the enrolment sequence
Incomplete outcome data (attrition bias) All outcomes	Low risk	Authors report that there were no patients lost to follow‐up and no patients refused to be treated 96 eligible subjects, 4 opted not to participate when counselled about the uncertainty of effectiveness, and 2 declined to randomise Finally, 90 eligible patients were enrolled
Selective reporting (reporting bias)	Unclear risk	Adverse events (abortion) reported‐ clinical outcomes reported‐ ‐ no registered protocol
Other bias	Low risk	There were no points to doubt the quality of the study The study was approved by the Institutional Review Board of Shen‐Zhen Maternity and Child Healthcare Hospital. All subjects signed an informed consent form