A total of 343 patients were included in this study, including 1065 cycles. 69 cycles had been cancelled before egg retrieval. Baseline characteristics of the patients are shown in Table 1.
The stimulation protocols and dosages of gonadotropins for each protocols of the 996 egg retrieval cycles are shown in Table 2. A total of 474 embryo transfer procedures were involved. The types of embryos transferred are shown in Table 3. The qualities of embryos transferred are shown in Table 4.
The number of patients who obtained oocyte retrieval operations, the number of patients who obtained live births and the number of patients who failed to obtained live birth but refused to receive further treatment in each cycle were showed in Fig. 1. Considering the small number of patients underwent 9 or more cycles of oocyte retrieval treatment, their information will be merged into one group.
The conservative estimate of CLBR and the optimal estimate of CLBR of the whole population and in different age group are shown in the Fig. 2. The live birth rate of the first oocyte retrieval cycle of the whole study subjects was 9.9%. After one or more cycles of treatments, a total of 141 couples achieved live births during the study period, with a conservative estimate CLBR of 41.1%. Assuming that the final outcome of the patients who did not continue to receive treatment had the same live birth rate with those who continued treatment, the optimistic estimate of CLBR was 81.0%. After calculating by age group, it was found that the older the female patient was, the lower the conservative and optimistic estimates of the CLBRs were. For women aged < 35 and 35 ~ 39, after 6 oocyte retrieval cycles, the conservative/optimistic estimates of CLBRs reached 57.4/82.7% and 41.1/64.8%, respectively. For elderly women ≥ 40 years old, the conservative/optimistic estimates of the CLBRs 6 oocyte retrieval cycles were only 14.7/26.0%.
The conservative and optimal estimates of CLBRs. A. whole population; B.patients age ＜35 years old; C.patients age 35~39 years old; D.patients age ≥40 years old)
The baseline characteristics, as well as the details regarding oocyte retrieval and embryo transfer, for patients who achieved live birth versus those who did not during the study period are presented in the Table 5. There are statistical differences in age, AMH level, AFC, the history of clinical pregnancy, the history of live birth, the number of oocytes retrieved per cycle, the number of embryo transfer procedure and the accumulative number of embryos transferred are different between the two groups.
Logistic regression analysis was performed on 8 variables mentioned before which were statistical difference between the group according to univariate analysis. The multivariate analysis results showed that: age and the number of oocyte retrieved per cycle were significantly associated with live birth outcomes (Table 6). The higher the age is, the lower the live birth rate is. A higher number of oocyte retrieved per cycle indicates a higher rate of live birth.
There are 195 patients(dropout group) who discontinued treatments after one or more unsuccessful cycles. A total of 141 patients achieved live births during the study period. There are 7 patients who continued treatment after 9 or more oocyte retrieval cycles although they did not achieved live births yet.
The baseline characteristics, the numbers of oocytes retrieved per cycle of the patients who discontinued treatments and other 148 patients(non-dropout group) during the period are showed in the Table 7. There are statistical differences in age, AMH level, AFC and the number of oocytes retrieved per cycle between the two groups.
The patients in dropout group received 512 cycles of oocyte retrieval, of which egg was not retrieved in 88 cycles (17.2%), and there was no transplantable embryo in 196 cycles (38.3%). The patients in non-dropout group received 484 cycles of oocyte retrieval, of which egg was not retrieved in 43 cycles (8.9%), and there was no transplantable embryo in 92 cycles (19.0%). There were significant differences in the proportion of cycles without oocytes and cycles without transplantable embryos between the two groups (P < 0.01, P < 0.01).
Treatment outcomes between different levels of AMH levels and different age groups are showed in the Tables 8 and 9.
