Intrauterine G-CSF in IUI cycles for women with thin endometrium may improve endometrial thickness and pregnancy rates: A randomized controlled study

Background Optimum endometrial thickness (ET) which grows in synchrony with growing follicle in stimulated intra-uterine insemination (IUI) cycles, is essential for achieving pregnancy. However, in some women, endometrium is unresponsive and fails to reach optimal thickness. Few studies have explored the role of intrauterine infusion of granulocyte colony-stimulating factor (G-CSF) to improve ET. This study was done to evaluate efficacy of intrauterine G-CSF infusion in improving ET, and pregnancy rates in IUI cycles with thin endometrium.

In this prospective randomized controlled study, 120 infertile women with thin endometrium (<7 mm) on the day of human chorionic gonadotropin (hCG) trigger were randomized. Study group (60) received 1 ml G-CSF (300 μg), by slow intrauterine infusion using IUI catheter. Control group (60) received 1 ml normal saline as placebo. hCG was administered at 2200 h on same day. ET was reassessed 36 h later by trans-vaginal scan (TVS) before IUI.

Twenty-seven (27) of 60 study group patients (45%) achieved optimal ET of ≥7 mm, whereas 19 of 60 control group patients (31.67%) achieved optimal ET. In the study group, 6 of 27 patients (22.22%) had positive urine pregnancy test, versus 3 of 19 patients (15.79%) in control group. Of these 5 patients (18.52%) in the study group and 2 patients (10.53%) in control group continued to have clinical pregnancy. Improved outcomes seen in G-CSF group were not statistically significant.

Our study suggests that G-CSF might have potential to improve ET and clinical pregnancy rate in women with thin endometrium undergoing IUI.

Endometrial thickness, Granulocyte colony stimulating factor, Intra uterine insemination, Human chorionic gonadotropin, Trans-vaginal scan

Optimum endometrial thickness (ET), a marker of endometrial receptivity, is one of the prerequisites for achieving clinical pregnancy. Various studies have shown that clinical pregnancy rates are significantly reduced when ET is < 7 mm.1 Most patients undergoing treatment for infertility are seen to achieve optimal ET synchronous with growing follicle. However, in some patients, the endometrium is unresponsive and fails to reach optimal thickness even with multiple treatment modalities such as extended oral estradiol, vaginal sildenafil, l-arginine, gonadotropin therapy, tamoxifen, or stem cell therapy. One such therapeutic approach for optimizing ET is the use of granulocyte colony-stimulating factor (G-CSF), a glycoprotein which mainly stimulates the granulocyte colony development and is produced by cells such as endothelial monocytes and endometrial cells. G-CSF plays a role in endometrial decidualization, trophoblastic development and placental metabolism.2 It promotes angiogenesis, reduces apoptotic activity, and also plays a role in the continuation of pregnancy by temporarily suppressing immune response by affecting lymphocytes, macrophages and T helper-2 cells.3 G-CSF instilled into the endometrial cavity or given systemically may prove to be effective in improving ET in women resistant to other therapies.4 G-CSF may act to stimulate the endometrial stem cells or mobilize the bone marrow stem cells to help in the growth of endometrium.5 In the reproductive tract, G-CSF is secreted in multiple ways. It is produced during ovulation by the granulosa cells where it enhances follicular growth and steroidogenesis, from endometrium during the luteal phase, inducing decidualization; and lastly, during gestation from placenta, hence favoring sustenance of pregnancy.6 G-CSF exerts its influence at various levels of the implantation process, suggesting its therapeutic benefits.7 Several studies have been done to evaluate the role of G-CSF in cases with suboptimal endometrium undergoing In-Vitro-Fertilization (IVF). The influence of G-CSF on thin endometrium was studied originally in a case series of patients previously resistant to treatment with estrogen and vasodilators.4 Subsequently, in a pilot study, increased ongoing clinical pregnancy rate was observed.8 These initial studies supported use of G-CSF prior to IVF in treatment of thin endometrium and suggested that, in adversely affected patients, G-CSF may result in low but reasonable clinical pregnancy rate. However, limited data is available regarding role of G-CSF in patients undergoing Intra Uterine Insemination (IUI). A gap about the role of G-CSF infusion prior to IUI remains, which may be filled by the current study. In the present study, G-CSF was administered intrauterine in patients with thin endometrium (<7 mm) and compared with placebo in stimulated IUI cycles.

This study was single-blind multi-centric randomized controlled study was approved by the local Institutional Ethics Committee. Good clinical care guidelines as per declaration of Helsinki were followed. One hundred twenty eligible patients undergoing IUI, meeting inclusion criteria were enrolled with informed consent from infertility OPD from two participating centers from July 2019 to June 2021. An IUI cycle was started in infertile women aged 20–40 years, patent tubes in hysterosalpingography, normal thyroid-stimulating hormone, and prolactin. Semen analysis of husband with total motile sperm count of more than 10 million was mandatory. These patients while undergoing IUI cycle, if observed to have ET < 7 mm on the day when at least one follicle was 18 mm in size, were included in the study. Women with severe endometriosis, endocrine disorders, congenital or acquired uterine anomaly, contraindications to G-CSF (renal disease, sickle cell disease, malignancy, past allergy or adverse effects), fibroids, polyps, Asherman's syndrome in diagnostic hysteroscopy, history of previous surgery on uterus, and partner's severe male factor infertility were excluded from the study. All infertility cases in whom IUI was planned underwent routine Trans-vaginal scan (TVS) on day 2 of spontaneous or progesterone-induced menstrual cycle. After confirming thin endometrium (ET < 5 mm), and ovaries down-regulated, letrozole 5 mg once daily orally for 5 days starting day 2 of menstrual cycle, and Inj human menopausal gonadotropin (hMG) 75 IU was administered intramuscular on days 6,7 and 8. The initial phase of the stimulation protocol was similar for all patients. TVS was done to assess follicular growth and ET on every alternate day from day 9 of cycle. It was performed by same gynecologist each time using Mindray DC-70 ultrasound machine with trans-vaginal probe of 3–11 MHz frequency range. Based on number and size of follicles, further dose and frequency of Inj hMG (75–150 IU) were individualized as per growth of follicle to achieve at least a single follicle of size 18–20 mm. All patients received oral estradiol 2 mg thrice daily on day 9 of cycle in case ET was <7 mm in the presence of a dominant follicle. No other treatment modality was offered to the participants during the intervention IUI cycle as per the study protocol. A computer-generated randomization table was used with separate randomization blocks for 120 such infertile women (ET < 7 mm by TVS, on day when at least one follicle of 18 mm size was seen) undergoing IUI cycle, and were randomized into study and control groups. The 60 study group patients were infused with single dose 1 ml (300 mcg) G-CSF administered by intra-uterine catheter as slow infusion before noon. 1 ml of normal saline was infused as placebo similar to G-CSF-based protocol in 60 control group patients. Inj hCG 10000 IU was administered by intramuscular route at 2200 h on same day. ET was reassessed 36 h later, prior to IUI. IUI was performed for all 120 study and control group patients, irrespective of ET achieved. IUI was done with semen preparation done by swim-up technique. Increase in ET to at least 7 mm measured by TVS, on the stipulated day of IUI was considered a positive outcome (primary endpoint). Pregnancy outcomes were assessed based on positive urine pregnancy test (UPT) done after 18 days suggestive of chemical pregnancy, and clinical pregnancy (gestational sac on TVS) seen after 4 weeks of IUI (secondary endpoint). Statistical analysis Descriptive analyses were carried out for all variables. Results were expressed as mean ± SD unless stated otherwise. Unpaired t test was done to look for difference in baseline characteristics among two treatment groups. Proportions in two groups were compared using chi-square test. Predictors of ET (if different) in two groups were found using multivariate linear regression and that of clinical pregnancy and positive UPT using logistic regression. P value < 0.05 was considered significant. Analyses were performed using SPSS27. Graphs were made using Graphpad Prism Ver 9.4.

Baseline characteristics of study and control group patients are as in Table 1. Mean age, BMI, AMH, FSH, and number of follicles grown in patients of both groups were well matched as shown in Table 1. Table 1. | G-CSF (n = 60) Study group | Placebo (n = 60) Control group | P value | Effect size | Mean difference and 95% CI | | |---|---|---|---|---|---| | Age (years) [Range in years] | 27.67 (±3.23) [22–35] | 27.28 (±2.92) [22–33] | 0.50 | 0.13 | 0.38 (−0.73, 1.50) | | BMI (kg/m2) | 25.05 (±2.22) | 24.52 (±2.30) | 0.20 | 0.23 | 0.53 (−0.28, 1.35) | | AMH (ng/ml) | 3.38 (±1.53) | 3.41 (±1.85) | 0.93 | −0.02 | −0.03 (−0.64, 0.59) | | Follicles (no.) [Range in no.] | 1.50 (±0.60) [1–3] | 1.35 (±0.52) [1–3] | 0.14 | 0.27 | 0.15 (−0.05, 0.35) | | FSH (mIU/ml) | 3.85 (±1.40) | 3.50 (±1.07) | 0.13 | 0.28 | 0.35 (−0.10, 0.79) | | ET before G-CSF (mm) [Range in mm] | 4.90 (±0.82) [3–6] | 4.87 (±0.77) [3–6] | 0.82 | 0.04 | 0.03 (−0.25, 0.32) | | ET after G-CSF (mm) [Range in mm] | 6.52 (±1.08) [4–9] | 6.27 (±0.82) [4–8] | 0.16 | 0.26 | 0.25 (−0.10, 0.60) | | Increase in ET (mm) | 1.62 (±1.01) | 1.40 (±1.00) | 0.24 | 0.22 | 0.22 (−0.15, 0.58) | | Type of infertility (primary) | 40 (66.67%) | 39 (65%) | 1 | || | Good endometrial response (≥7 mm) | 27 (45%) | 19 (31.7%) | 0.19 | Data are presented as Mean (±SD), ∗Analysis was performed using the t-test and ∗∗Chi-square test (BMI: Body mass index; AMH: Anti-Müllerian hormone; FSH: Follicle-stimulating hormone). Twenty (20) of 60 patients receiving G-CSF; and 21 of 60 in placebo group had secondary infertility (Fisher's exact test p = 1). The cause(s) of infertility in G-CSF and placebo groups were quite similar as in Table 2. Table 2. | Causes, n (%) | G-CSF (n = 60) Study group | Placebo (n = 60) Control group | |---|---|---| | 1. Male factor | 11 (18.3%) | 13 (21.6%) | | 2. PCOS | 16 (26.7%) | 16 (26.7%) | | 3. Unexplained | 24 (40%) | 21 (35%) | | 4. Endometriosis | 4 (6.7%) | 6 (10%) | | 5. Poor ovarian reserve | 5 (8.3%) | 4 (6.7%) | Mean ET before and after intervention in the study (G-CSF) arm was 4.90 mm and 6.52 mm, while in control (saline) arm was 4.87 mm and 6.27 mm respectively. Mean increase in ET in G-CSF arm was higher at 1.62 mm versus 1.40 mm in placebo arm, though statistically not significant (p = 0.24) as in Fig. 1. The rates of chemical pregnancy (positive UPT) and clinical pregnancy (gestational sac on USG) in the study and control groups are shown in Fig. 2, Fig. 3, respectively. The proportion between two groups was statistically not different (Fisher's exact test, p = 0.53 and p = 0.49, respectively), as in Table 3. Table 3. | Chemical Pregnancy | ||| |---|---|---|---| | Treatment | UPT Positive | Difference and 95% CI | p value | | G-CSF group | 11.67% (n = 7) | 5% (−5.3, 15.3) | 0.53 | | Placebo group | 6.67% (n = 4) | || | Clinical pregnancy | ||| | Treatment | Gestational Sac seen | Difference and 95% CI | p value | | G-CSF group | 10% (n = 6) | 5% (−4.4, 14.4) | 0.49 | | Placebo group | 5% (n = 3) | Proportion of patients in the two groups who achieved ET of at least 7 mm on the stipulated day of IUI was the primary endpoint (p value is 0.19 with relative risk of achieving ET ≥ 7 mm with G-CSF being 1.24 with 95% CI of 0.94–1.68). In the study group, 45% patients achieved optimal ET of ≥7 mm (primary endpoint), while only 31.67% control group patients achieved optimal ET. Of those who achieved optimal ET, 22.22% patients in the study group versus 15.79% patients in control group had chemical pregnancy. In the study group, 18.52% patients and in control group 10.53% patients had clinical pregnancy (secondary endpoint), as shown in Table 4 and Fig. 4. Table 4. | G-CSF (n = 60) (Study group) | Placebo (n = 60) (Control group) | Difference and 95% CI | p value | | |---|---|---|---|---| | ET (in mm) | |||| | a. <7 mm; n (%) | 33 (55%) | 41 (68.33%) | || | Positive UPT | 1 (3.03%) | 1 (2.44%) | || | Clinical pregnancy | 1 (3.03%) | 1 (2.44%) | || | b.≥7 mm; n (%) | 27 (45%) | 19 (31.67%) | || | Positive UPT | 6 (22.22%) | 3 (15.79%) | 6.43% (−16.26, 29.12) | 0.72 | | Clinical pregnancy | 5 (18.52%) | 2 (10.53%) | 7.99% (−12.14, 28.12) | 0.68 | In the study group, 55% patients, compared to 68.33% patients in the control group, continued to have unresponsive thin endometrium as in Table 4.

The results of the current study suggest that G-CSF compared to placebo, improved ET in patients with thin endometrium in IUI cycles, although the improvement was not statistically significant (Fig. 1). The rates of chemical and clinical pregnancy between the two groups were not different (Table 3). Results further suggest that higher percentage of patients achieved ET ≥ 7 mm (primary endpoint) with G-CSF, and consequently higher percentage of pregnancy rate (secondary endpoint), although statistically non-significant, suggesting potential for enhanced implantation as in Table 4 and Fig. 4. Majority studies have assessed the role of G-CSF prior to IVF cycles. In the earliest case series uterine infusion of G-CSF was used off-label in four patients with thin endometrium resistant to estrogen and vasodilators undergoing IVF. An improvement in ET to at least 7 mm and conception was achieved in all cases.4 This initial success paved way for further studies to assess potential role of G-CSF for increasing ET and clinical pregnancy in patients undergoing IVF with unresponsive thin endometrium. Gleicher et al., in their next prospective pilot study on 21 patients undergoing first IVF cycles, in whom estrogen and sildenafil had failed to achieve an optimal ET of 7 mm, showed significant increase in ET with use of G-CSF. Three patients required second infusion of G-CSF to achieve ET of at least 7 mm and all underwent embryo transfers on day 3. By then all had achieved ET ≥ 7 mm. Clinical pregnancy rate observed in this study was 19.1%. It is however difficult to say whether expansion of endometrium was due to G-CSF alone or due to synergistic effect of G-CSF and sildenafil, which all patients received in this study. Final endometrial measurement in this study was done on the day of embryo transfer (Day 3), 5 days after first G-CSF instillation.8 In the study by Kunicki et al., 37 women with resistant thin endometrium were given G-CSF prior to second IVF cycles, and ET was assessed 72 h after G-CSF infusion. They found a significant increase in ET, and increased clinical pregnancy rate of 18.9%, quite reasonable for patients with resistant endometrium.9 However, in our study ET measurement was done after 48 h of G-CSF infusion. Sarvi et al., in the study of 13 women receiving G-CSF versus 15 women receiving saline by intrauterine infusion for thin endometrium undergoing IVF, also found significant increase in ET at 48 h, enhanced implantation rate of 10.3%, while no difference in clinical pregnancy rate in G-CSF group was seen.10 All these studies done among patients undergoing IVF did find either improved ET or increased clinical pregnancy rates though not reaching at par with average IVF outcomes. Xu et al., in patients with thin endometrium undergoing frozen embryo transfer (FET), used G-CSF in cycles stimulated with letrozole and hMG on day when dominant follicle of 12 mm was seen, whereas most other studies infused intrauterine G-CSF on the day of hCG trigger. They hypothesized that G-CSF may play a physiological role in endometrial development, not just in late proliferative phase but throughout the menstrual cycle through interactions with other cytokines and ovarian steroid hormones. Once primed with G-CSF, estrogen might have additional nutritive value to endometrial growth.11 They did find significant increase in ET, clinical pregnancy rate (48.1%) and implantation rate which was partly due to low mean age of all patients in their study as compared to other studies.8,9,10 and also due to significantly improved ET. Patients had relatively longer in vivo exposure time for G-CSF to act in their study. A clinical pregnancy rate at par with routine IVF cycles might be due to lesser average age and probably longer exposure time to G-CSF required for its optimal effect. The average age of patients in our study was 27.67 years which also probably contributed to favorable results. Eftekhar et al. did not find any improvement in ET, but showed improvement in chemical and clinical pregnancy rate of women with thin endometrium in thawed FET cycle. They hypothesized that it might be the effect of mechanism of G-CSF in increasing Leukemia Inhibitory Factor and decreasing CD16, CD56, an important factor for implantation.12 This is consistent with the present study since it does bring out improved implantation potential shown by G-CSF.

of systematic review by Kamath et al., found no significant increase in ET following G-CSF instillation compared to no intervention or placebo in women with thin endometrium, but significantly higher pregnancy rate both in patients with thin endometrium and with recurrent implantation failure compared to control group with low quality evidence.13 Cochrane review by Kamath et al., again could not ascertain with certainty whether G-CSF administration reduces miscarriage rate or improves clinical pregnancy rate compared to no intervention or placebo in sub-fertile women undergoing ART both in subpopulations of unselected IVF group and women with thin endometrium.14 G-CSF has been used successfully as treatment for implantation failure, repeated miscarriages and poor ovarian response when administered by subcutaneous rather than intrauterine route.3,15,16,17 It is still not certain as to which delivery route (intravenous/subcutaneous/intrauterine) is superior. In addition, in some of these studies G-CSF was administered earlier in cycle, acting for longer time duration which suggests that it might be more beneficial to administer it early and more frequently in cycle. Literature is scarce on use of intrauterine infusion of G-CSF prior to IUI. One study evaluated the role of G-CSF in improving implantation and not ET in IUI cycles.18 As in the present study, this study also observed statistically insignificant improvement in pregnancy rate. A similar study by Singh et al., without control group, found statistically significant increase in ET after intrauterine infusion of G-CSF.19 The current study was carried out to assess the therapeutic effect of G-CSF in the patients undergoing IUI at the study centers. Although there was improvement in ET and pregnancy rates observed in intervention group, it however did not reach statistical significance. Explanation for this may be that increase in ET was observed after a duration of 48 h, while in initial studies it was observed on the day of embryo transfer, at least 5 days after G-CSF instillation with one or more doses.8,13 The main limitation of this study is the single-blind randomization which could have introduced bias in results. The study and control groups were further divided into those with optimal ET (≥7 mm) and suboptimal ET (<7 mm) after intervention for assessment of endpoints, making sample size small. Considering an increase in ET of 1.62 mm in G-CSF arm and 1.40 mm in placebo arm, SD of 1.01, power of 80% and type I error of 5%, 331 patients would have been required in each arm.

In affirmation to the hypothesis that G-CSF might in addition to its proliferative effects on endometrium also beneficially affect implantation, our study suggests the potential benefit of G-CSF in enhancing IUI cycle outcomes by improving ET. Large-scale prospective randomized controlled trial may confirm the role of G-CSF in women with thin endometrium undergoing IUI and determine its best route, dose and frequency. Patients/ Guardians/ Participants consent Patients/participants informed consent was obtained. Ethical clearance Institute/hospital ethical clearance certificate was obtained. Source of support This paper is based on Armed Forces Medical Research Committee Project No. 5236A/2019 granted and funded by the office of the Directorate General Armed Forces Medical Services and Defence Research Developement Organization, Government of India. Disclosure of competing interest The authors have none to declare. Acknowledgment We gratefully acknowledge the Dr. Harshit Khurana, Professor (Medicine) & Clinical Hematologist & Head (Geriatrics Medicine), Armed Forces Medical College, Pune.

- 1.Casper R.F. It's time to pay attention to the endometrium. Fertil Steril. 2011;96:519–521. doi: 10.1016/j.fertnstert.2011.07.1096. [DOI] [PubMed] [Google Scholar] - 2.Rahmati M., Petitbarat M., Dubanchet S., Bensussan A., Chaouat G., Ledee N. Granulocyte-Colony Stimulating Factor related pathways tested on an endometrial ex-vivo model. PLoS One. 2014;9 doi: 10.1371/journal.pone.0102286. [DOI] [PMC free article] [PubMed] [Google Scholar] - 3.Würfel W., Santjohanser C., Hirv K., et al. High pregnancy rates with administration of granulocyte colony-stimulating factor in ART-patients with repetitive implantation failure and lacking killer-cell immunglobulin-like receptors. Hum Reprod Oxf Engl. 2010;25:2151–2152. doi: 10.1093/humrep/deq106. [DOI] [PMC free article] [PubMed] [Google Scholar] - 4.Gleicher N., Vidali A., Barad D.H. Successful treatment of unresponsive thin endometrium. Fertil Steril. 2011;95:2123. e13–e17. doi: 10.1016/j.fertnstert.2011.01.143. [DOI] [PubMed] [Google Scholar] - 5.Gargett C.E., Ye L. Endometrial reconstruction from stem cells. Fertil Steril. 2012;98:11–20. doi: 10.1016/j.fertnstert.2012.05.004. [DOI] [PubMed] [Google Scholar] - 6.Duan J.S. Production of granulocyte colony stimulating factor in decidual tissue and its significance in pregnancy. Osaka City Med J. 1990;36:81–97. [PubMed] [Google Scholar] - 7.Ledee N., Gridelet V., Ravet S., et al. Impact of follicular G-CSF quantification on subsequent embryo transfer decisions: a proof of concept study. Hum Reprod. 2013;8:406–413. doi: 10.1093/humrep/des354. [DOI] [PMC free article] [PubMed] [Google Scholar] - 8.Gleicher N., Kim A., Michaeli T., et al. A pilot cohort study of granulocyte colony-stimulating factor in the treatment of unresponsive thin endometrium resistant to standard therapies. Hum Reprod. 2013;7:172–177. doi: 10.1093/humrep/des370. [DOI] [PubMed] [Google Scholar] - 9.Kunicki M., Łukaszuk K., Woclawek-Potocka I., Liss J., Kulwikowska P., Szczyptańska J. Evaluation of granulocyte colony-stimulating factor effects on treatment-resistant thin endometrium in women undergoing in vitro fertilization. BioMed Res Int. 2014;30:1–5. doi: 10.1155/2014/913235. [DOI] [PMC free article] [PubMed] [Google Scholar] - 10.Sarvi F., Arabahmadi M., Alleyassin A., Aghahosseini M., Ghasemi M. Effect of increased endometrial thickness and implantation rate by granulocyte colony-stimulating factor on unresponsive thin endometrium in fresh in vitro fertilization cycles: a randomized clinical trial. Obstet Gynecol Int. 2017;2017:1–6. doi: 10.1155/2017/3596079. [DOI] [PMC free article] [PubMed] [Google Scholar] - 11.Xu B., Zhang Q., Hao J., Xu D., Li Y. Two protocols to treat thin endometrium with granulocyte colony-stimulating factor during frozen embryo transfer cycles. Reprod Biomed. 2015;7:349–358. doi: 10.1016/j.rbmo.2014.12.006. [DOI] [PubMed] [Google Scholar] - 12.Eftekhar M., Sayadi M., Arabjahvani F. Transvaginal perfusion of G-CSF for infertile women with thin endometrium in frozen ET program: a non-randomized clinical trial. Iran J Reproductive Med. 2014;12:661–666. [PMC free article] [PubMed] [Google Scholar] - 13.Kamath M.S., Chittawar P.B., Kirubakaran R., Mascarenhas M. Use of granulocyte-colony stimulating factor in assisted reproductive technology: A systematic review and meta-analysis. Eur J Obstet Gynecol Reprod Biol. 2017 Jul;214:16–24. doi: 10.1016/j.ejogrb.2017.04.022. Epub 2017 Apr 13. PMID: 28458165. [DOI] [PubMed] [Google Scholar] - 14.Kamath M.S., Kirubakaran R., Sunkara S.K. Granulocyte-colony stimulating factor administration for subfertile women undergoing assisted reproduction. Cochrane Database Syst Rev. 2020:CD013226. doi: 10.1002/14651858.CD013226.pub2. 1. [DOI] [PMC free article] [PubMed] [Google Scholar] - 15.Stamenov D.S., Penkova K.L., Persenska S.K., Chaushev T.A., Rangelov, Baltadzhieva D.N. Intracavitar uterine granulocyte-colony-stimulatory factor (G-CSF) application- A possible treatment in recurrent implantation failure. Fertil Steril. 2011;96:93. [Google Scholar] - 16.Scarpellini F., Sbracia M. Effectiveness of GM-CSF 1 in the treatment of habitual abortion in a controlled study. Fertil Steril. 2003;80:288. [Google Scholar] - 17.Takasaki A., Ohba T., Okamura Y., et al. Clinical use of colony-stimulating factor-1 in ovulation induction for poor responders. Fertil Steril. 2008;90:2287–2290. doi: 10.1016/j.fertnstert.2007.10.043. [DOI] [PubMed] [Google Scholar] - 18.Amooee S., Shomali Z., Namazi N., Jannati F. Is there any role for granulocyte colony stimulating factor in improvement of implantation in intrauterine insemination?? a prospective double-blind randomized control trial. Int J Fertil Steril. 2022;16(4) doi: 10.22074/IJFS.2021.537125.1171. [DOI] [PMC free article] [PubMed] [Google Scholar] - 19.Kumari S., Singh K., Tiwary B., Kumari S., Nishat H. The effect of intrauterine instillation of G-CSF in infertile women with thin endometrium in IUI cycle. Int J Sci Res. April, 2021;10(04) doi: 10.36106/ijsr. [DOI] [Google Scholar]