Pregnancy Outcomes in Double Stimulation versus Two Consecutive Mild Stimulations for IVF in Poor Ovarian Responders

To compare pregnancy outcomes between double stimulation (DouStim) and two consecutive mild stimulations in poor ovarian responders, this study retrospectively analyzed 281 patients diagnosed as having poor ovarian response (POR) who underwent oocytes retrieval for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) from January 2018 to December 2020. They were divided into two groups: the DouStim group (n = 89) and the two consecutive mild stimulations group (n = 192). The results illustrated that there were no significant differences in the number of oocytes and 2PNs between the two groups. The number of frozen embryos [1 (0, 2) versus 1(0, 2)] was significantly lower and the proportion of patients without frozen embryos (39.3% versus 26.0%) was significantly higher in the DouStim group than in the two consecutive mild stimulations group (p < 0.05). There were no significant differences in the clinical pregnancy rate (CPR) and the cumulative live birth rate (CLBR) between the two groups (p > 0.05). The intra-subgroup comparison showed that in young POR patients under 35 years old, there were no significant differences in clinical indicators and pregnancy outcomes (p > 0.05). In elderly POR patients aged 35 years and above, the number of frozen embryos [1 (0, 1.5) versus 1 (0.25, 2)] (p < 0.01) was significantly lower in the DouStim group than in the two consecutive mild stimulations group, but the pregnancy outcomes were not significantly different (p > 0.05). In conclusion, the DouStim protocol is inferior to the two consecutive mild stimulations protocol in terms of the number of frozen embryos, which mainly occurs in elderly patients, but there is no difference in pregnancy outcomes between the two protocols.