Clinical effect of ovarian stimulation during continuous luteal phase after mini-stimulation protocol in patients with poor ovarian response

Abstract

Objective To observe the effect of ovarian stimulation during continuous luteal phase after mini-stimulation protocol in patients with poor ovarian response (POR) receiving in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET). Methods A study of 144 cases following IVF/ICSI-ET was performed in the Third Affiliated Hospital of Zhengzhou University from June 2016 to December 2017. All patients received mini-stimulation regimen (mini-stimulation group). After ovulation, continuous luteal phase stimulation was performed (luteal phase group). According to the semen condition of the male, IVF or ICSI was selected. All the available embryos could be frozen and transferred in the next cycle. The clinical and laboratory indicators and pregnancy outcomes of the two ovulation-promoting protocols were compared. Results 1) In the luteal phase group, the estradiol [(1 043.28±744.77) ng/L vs. (672.47±586.67)ng/L] and progesterone levels [(6.29±0.73) IU/L vs. (1.21±0.94) IU/L] on the human chorionic gonadotropin (hCG) injection day were higher than those of the mini-stimulation group, and the luteinizing hormone (LH) levels on the hCG injection day [(3.74±2.93) IU/L vs. (8.45±5.81) IU/L] were lower than those of the mini-stimulation group, differences were statistically significant (P 0.05). 2) The number of retrieved oocytes in the mini-stimulation group and the luteal phase group presented a non-normal distribution, which was expressed by the median and quartile spacing. The number of retrieved oocytes were divided into 0-1, 2-3, >3, and the corresponding cases were 70 vs. 45, 53 vs. 64, 21 vs. 35. Non-parametric rank sum test was applied, and the results showed that the number of retrieved oocytes in the luteal phase group was higher than that in the mini-stimulation group, and the difference was statistically significant (P=0.022). Available embryos [1.0(0.0,2.0) vs. 1.0(0.0,2.0)], two pronucleus (2PN) fertilization rate (70.7% vs. 65.3%), high-quality embryo rate (40.3% vs. 38.9%), premature ovulation rate (6.3% vs. 9.0%) were not statistically different between the two protocols (P>0.05). 3) The number of transplanted embryos (1.53±0.51 vs. 1.57±0.54), the clinical pregnancy rate (18.4% vs. 28.3%) and the miscarriage rate (22.2% vs. 23.5%) were not statistically different between the two groups (P>0.05). Conclusion Patients with POR can obtain more oocytes, increase available embryos and promote cumulative pregnancy rate. Moreover, the lower level of LH on the hCG injection day during luteal phase ovarian stimulation indicated that the high progesterone level in the luteal phase plays a significant role in down regulation, which is a safe and feasible program. Key words: Fertilization in vitro; Intracytoplasmic sperm injection; Poor ovarian response; Mini-stimulation; Luteal phase ovarian stimulation; Embryo transfer