Abstract: We included 15 trials involving 622 women who received G-CSF and 631 women who received placebo or no additional treatment during IVF. The main limitations in the quality of the evidence were inadequate reporting of study methods and high risk of performance bias due to lack of blinding. We assessed only two of the 15 included trials as at a low risk of bias. None of the trials reported the primary effectiveness outcome of live-birth rate. We are uncertain whether G-CSF administration improves ongoing pregnancy rate compared to control in subfertile women undergoing ART (RR 1.42, 95% confidence interval (CI) 0.83 to 2.42; 2 RCTs; participants = 263; I² = 0%; very low-quality evidence). For a typical clinic with 14% ongoing pregnancy rate, G-CSF administration would be expected to result in ongoing pregnancy rates between 12% and 35%. We are uncertain whether G-CSF administration reduces miscarriage rate (Peto odds ratio 0.55, 95% CI 0.17 to 1.83; 3 RCTs; participants = 391; I² = 0%; very low-quality evidence) compared to the control group in subfertile women undergoing ART. We are uncertain whether G-CSF administration improves overall clinical pregnancy rate compared to control in subfertile women undergoing ART (RR 1.63, 95% CI 1.32 to 2.01; 14 RCTs; participants = 1253; I² = 13%; very low-quality evidence). For a typical clinic with 17% clinical pregnancy rate, G-CSF administration would be expected to result in clinical pregnancy rates between 23% and 35%. In the unselected IVF population, we are uncertain whether G-CSF administration improves clinical pregnancy rate compared to the control group (RR 1.11, 95% CI 0.77 to 1.60; 3 RCTs; participants = 404; I² = 0%; low-quality evidence). G-CSF administration may improve clinical pregnancy rate in women with two or more previous IVF failures compared to the control group (RR 2.11, 95% CI 1.56 to 2.85; 7 RCTs; participants = 643; I² = 0%; low-quality evidence). In subfertile women with thin endometrium undergoing ART, we are uncertain whether G-CSF administration improves clinical pregnancy rate compared to the control group (RR 1.58, 95% CI 0.95 to 2.63; 4 RCTs; participants = 206; I² = 30%; low-quality evidence). No study reported on multiple pregnancy rate. Only four trials reported adverse events as an outcome, and none of them reported any major adverse events following either G-CSF administration or placebo/no treatment. In subfertile women undergoing ART, we are uncertain whether the administration of G-CSF improves ongoing pregnancy or overall clinical pregnancy rates or reduces miscarriage rate compared to no treatment or placebo, whether in all women or those with thin endometrium, based on very low-quality evidence. Low-quality evidence suggests that G-CSF administration may improve clinical pregnancy rate in women with two or more IVF failures, but the included studies had unclear allocation concealment or were at high risk of performance bias.

Plain-language summary: We found 15 trials (1253 women) comparing G-CSF with placebo or no treatment. Eleven trials evaluated the role of G-CSF in women undergoing IVF, with a majority of trials including those women with two or more failed attempts. The remaining four trials investigated the role of G-CSF in women with thin endometrium undergoing IVF. The evidence is current to February 2019. We are uncertain whether giving G-CSF in women undergoing IVF improves chances of ongoing pregnancy or overall clinical pregnancy rates or reduces miscarriage rate compared to placebo or no treatment. For a typical clinic with 14% ongoing pregnancy rate, G-CSF administration would be expected to result in ongoing pregnancy rates between 12% and 35%. No study reported on multiple pregnancy rate. Only four trials reported adverse events as an outcome, and none of them reported any major adverse events following either G-CSF administration or placebo/no treatment. We are uncertain whether giving G-CSF improves ongoing pregnancy or reduces miscarriage rates in women undergoing IVF based on very low-quality evidence. The quality of the evidence was reduced because of risk of bias.