Poor ovarian response and the possible role of natural and modified natural cycles

Comparison of embryo quality and pregnancy outcomes for patients with low ovarian reserve in natural cycles and mildly stimulated cycles: a cohort study

BACKGROUND

As women with low ovarian reserve embark on the challenging journey of in-vitro fertilisation (IVF) treatment, the choice between natural and mildly stimulated cycles becomes a pivotal consideration. It is unclear which of these two regimens is superior for women with low ovarian reserve. Our study aims to assess the impact of natural cycles on embryo quality and pregnancy outcomes in women with low ovarian reserve undergoing IVF treatment compared to mildly stimulated cycles.

METHODS

This retrospective study enrolled consecutive patients with low ovarian reserve who underwent IVF/intracytoplasmic sperm injection (ICSI) at Guangdong Second Provincial General Hospital between January 2017 and April 2021. The primary outcome for pregnancy rate of 478 natural cycles and 448 mild stimulated cycles was compared. Secondary outcomes included embryo quality and oocyte retrieval time of natural cycles.

RESULTS

The pregnancy rate in the natural cycle group was significantly higher than that in the mildly stimulated cycle group (51.8% vs. 40.1%, p = 0.046). Moreover, natural cycles exhibited higher rates of available embryos (84.1% vs. 78.6%, p = 0.040), high-quality embryos (61.8% vs. 53.2%, p = 0.008), and utilisation of oocytes (73% vs. 65%, p = 0.001) compared to mildly stimulated cycles. Oocyte retrievals in natural cycles were predominantly performed between 7:00 and 19:00, with 94.9% occurring during this time frame. In natural cycles with high-quality embryos, 96.4% of oocyte retrievals were also conducted between 7:00 and 19:00.

CONCLUSION

Natural cycles with appropriately timed oocyte retrieval may present a valuable option for patients with low ovarian reserve.

Do women with severely diminished ovarian reserve undergoing modified natural-cycle in-vitro fertilization benefit from earlier trigger at smaller follicle size?

OBJECTIVE

To evaluate whether trigger and oocyte collection at a smaller follicle size decreases the risk of premature ovulation while maintaining the reproductive potential of oocytes in women with a severely diminished ovarian reserve undergoing modified natural-cycle in-vitro fertilization.

METHODS

This was a retrospective cohort study including women who had at least one unsuccessful cycle (due to no response) of conventional ovarian stimulation with a high dosage of gonadotropins and subsequently underwent a modified natural cycle with a solitary growing follicle (i.e. only one follicle > 10 mm at the time of trigger). The association between follicle size at trigger and various cycle outcomes was tested using regression analyses.

RESULTS

A total of 160 ovarian stimulation cycles from 110 patients were included in the analysis. Oocyte pick-up (OPU) was performed in 153 cycles and 7 cycles were canceled due to premature ovulation. Patients who received their trigger at smaller follicle sizes (≤ 15 mm) had significantly lower rates of premature ovulation and thus higher rates of OPU (98.9% vs 90.8%; odds ratio, 9.56 (95% CI, 1.58-182.9); P = 0.039) compared with those who received their trigger at larger follicle sizes (> 15 mm). On multivariable analysis, smaller follicle sizes at trigger (> 10 to 13 mm, > 13 to 15 mm, > 15 mm to 17 mm) were not associated significantly with a lower rate of cumulus-oocyte complex (COC) retrieval, metaphase-II (MII) oocytes or blastulation when compared to the > 17-mm group. On sensitivity analysis including only the first cycle of each couple, the maturity rate among those with COC retrieval was highest in follicle sizes > 15 to 17 mm (92.3%) and > 13 to 15 mm (91.7%), followed by > 10 to 13 mm (85.7%) and lowest in the > 17-mm group (58.8%). During the study period, five euploid blastocysts developed from 48 fertilized MII oocytes with follicle sizes of 12 mm (n = 3), 14 mm (n = 1) and 16 mm (n = 1) at trigger. Of those, four were transferred and resulted in two live births, both of which developed from follicles with a size at trigger of 12 mm.

CONCLUSIONS

The ideal follicle size for triggering oocyte maturation may be smaller in women with a severely diminished ovarian reserve managed on a modified natural cycle when compared to conventional cut-offs. The risk of OPU cancellation was significantly higher in women triggered at follicle size > 15 mm and the yield of mature oocytes was not adversely affected in women triggered at follicle size > 13 to 15 mm compared with > 15 to 17 mm. Waiting for follicles to reach sizes > 17mm may be detrimental to achieving optimal outcome. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Comparative efficacy of different growth hormone supplementation protocols in improving clinical outcomes in women with poor ovarian response undergoing assisted reproductive therapy: a network meta-analysis

Growth hormone (GH) has a long-standing history of use as an adjunctive therapy in the treatment of poor ovarian response (POR), but the optimal dosage and timing remains unclear. The aim of this study was to evaluate and compare the efficacy of different GH supplementation protocols through a network meta-analysis (NMA) and determine the optimal treatment protocol. This study was reported based on the Preferred Reporting Items for Systematic Reviews for Network Meta-Analysis (PRISMA-NMA) statement. Databases including PubMed, Web of Science, Cochrane Library and Embase were searched until June 2023. A total of 524 records were retrieved in our search, and 23 clinical studies comprising 4889 cycles were involved. Seven different GH protocols were identified. Results showed that compared to the control group, daily administration of 4-8 IU of GH during the follicular phase of the stimulation cycle had the best comprehensive therapeutic effects on improving the number of retrieved oocytes, mature oocytes, endometrial thickness, and reducing gonadotropin requirements in POR patients undergoing assisted reproductive therapy, with a relatively brief treatment duration and a moderate total GH dose. Subgroup analysis demonstrated that this protocol could significantly improve the clinical pregnancy rate of POR patients in the randomized controlled trials (RCT) subgroup and the African subgroup. Therefore, its clinical application is suggested. Besides, the potential advantages of long-term GH supplementation protocol (using GH for at least 2 weeks before oocyte retrieval) has merit for further research. Rigorous and well-designed multi-arm RCTs are needed in the future to confirm the conclusions drawn from this study.