Study question: Is thin endometrium unresponsive to standard treatments expandable by intrauterine perfusion with granulocyte colony-stimulating factor (G-CSF)?
Summary answer: This cohort study is supportive of the effectiveness of G-CSF in expanding chronically unresponsive endometria.
What is known already: In a previous small case series, we reported the successful off-label use of G-CSF in four consecutive patients, who had previously failed to expand their endometria beyond 6.9 mm with the use of standard treatments.
Study design, size and duration: In a prospective observational cohort pilot study over 18 months, we described 21 consecutive infertile women with endometria <7 mm on the day of hCG administration in their first IVF cycles at our center. All previous cycles using traditional treatments with estradiol, sildenafil citrate (Viagra™) and/or beta-blockers had been unsuccessful. G-CSF (Nupogen™) was administered per intrauterine catheter by slow infusion before noon on the day of hCG administration. If the endometrium had not reached at least a 7-mm within 48h, a second infusion was given following oocyte retrieval. Primary and secondary main outcomes were an increase in endometrial thickness and clinical pregnancy, respectively. Endometrial thickness was assessed by vaginal ultrasound at the most expanded area of the endometrial stripe.
Participants/materials, settings and method: This study was uncontrolled, each patient serving as her own control in a prospective evaluation of endometrial thickness. The mean ± SD age of the cohort was 40.5 ± 6.6 years, gravidity was 1.8 ± 2.1 (range 0-7) and parity was 0.4 ± 1.1 (range 0-4); 76.2% of women had, based on age-specific FSH and anti-Müllerian hormone, an objective diagnosis of diminished ovarian reserve and had failed 2.0 ± 2.1 prior IVF cycles elsewhere.
Main results and the role of chance: With 5.2 ± 1.9 days between G-CSF perfusions and embryo transfers, endometrial thickness increased from 6.4 ± 1.4 to 9.3 ± 2.1 mm (P < 0.001). The Δ in change was 2.9 ± 2.0 mm, and did not vary between conception and non-conception cycles. A 19.1% ongoing clinical pregnancy rate was observed, excluding one ectopic pregnancy.
Limitations and reasons for caution: Small sample size (but a highly selected patient population) in an uncontrolled cohort study and in unselected first IVF cycles at our center.
Wider implications of the findings: This pilot study supports the utility of G-CSF in the treatment of chronically thin endometrium and suggests that such treatment will, in very adversely affected patients, result in low but very reasonable clinical pregnancy rates.
Study funding/competing interest(s): This work was supported by the Foundation for Reproductive Medicine, New York, New York, USA, a not-for-profit research foundation and intramural grants from the Center for Human Reproduction (CHR)-New York. N.G. and D.H.B. are members of the board of the Foundation for Reproductive Medicine. N.G. is owner of CHR-New York, where the study was conducted. N.G. and D.H.B. have been recipients of research awards, travel grants and speaker honoraria from various pharmaceutical and medical device companies. None of these companies was, however, in any way associated with the materials and the manuscript presented here. N.G. and D.H.B. are listed as co-inventors on a number of awarded and still pending U.S. patents, none related to the materials presented here. N.G. is on the board of a medically related company, not in any way associated with the data presented here.