Ovulation induction with high progesterone levels may be more suitable for elderly patients with low ovarian response

The objective of this study was to explore the outcomes of using the progestin-primed ovarian stimulation (PPOS) protocol in aged infertile women. The patients recruited in the study had displayed a poor ovarian response (POR) in the first IVF/ICSI-ET cycles with the ultra-short gonadotropin-releasing hormone agonist (GnRH-a) protocols.

A self-controlled retrospective study was conducted to investigate the clinical outcomes of 117 aged infertile women who met the inclusion criteria. The patients were grouped into two; group B included patients who had displayed a poor ovarian response (POR) in the first IVF/ICSI-ET cycle with the ultra-short GnRH-a protocol. Group A was made up of patients who underwent the PPOS protocol in the second cycle. The study was done between January 2015 to May 2018 in the reproductive and genetic centre of integrated traditional and western medicine, Affiliated hospital of Shandong University of traditional Chinese medicine. Reproduction-related clinical outcomes in the two groups were compared.

There were no statistically significant differences in the serum levels of LH, E_2, and P on the trigger day between group A and group B (P＞0.05). The number of follicles with a diameter > 14 mm was significantly higher in the PPOS protocol patients than in the ultra-short GnRH-a protocol group (4.83 ± 2.82 vs. 3.25 ± 2.53, P < 0.01). The duration and total dosage of gonadotropin of the PPOS protocol group were less than in the previous ultra-short GnRH-a protocol, although the statistical differences were not significant (P > 0.05). The number of eggs obtained in the PPOS group was significantly higher than that of the previous one (4.29 ± 3.11 vs. 2.76 ± 2.33, P < 0.05). The numbers of MII eggs, cleavage, 2 P N, transplantable embryos, and high quality embryos were higher in the PPOS protocol group than that in the ultra-short protocol group. However, the differences between the two groups in all the above parameters were not statistically significant (P > 0.05). The rate of high-quality embryos was significantly higher in the PPOS protocol group than in the ultra-short protocol group (38.61(100/259) vs. 32.02(65/203), P < 0.05). Although not statistically significant (P > 0.05), the abortion rate of the PPOS protocol group was higher than that of the ultra-short protocol group. The clinical pregnancy and live birth rates were significantly higher in the PPOS protocol group than in the ultra-short protocol group (p < 0.05). The clinical pregnancy rates in the PPOS protocol group and the ultra-short protocol group were 32.35 % and 25.53 % respectively while the live birth rates were 27.45 % and 21.28 % respectively.

Compared with the ultra-short protocol, the PPOS protocol improves the number of follicles, the number of eggs, clinical pregnancy, and live birth rates in POR patients. The PPOS protocol could, therefore, provide a novel treatment strategy for inducing ovulation in POR patients.