Pregnancy outcomes after subsequent transfer stratified by LM causes
Pregnancy outcomes after subsequent transfer turned out as shown inFigure Ⅰ . Compared with general IVF population, women with a previous unLM displayed a significantly higher risk of EM after subsequent embryo transfer (8.28% vs. 13.47%, P=0.003, RR=1.725, 95% CI,1.204-2.470). Moreover, the recurrence risk of LM was significantly higher (for unLM: 4.24% vs. 9.43%, P=0.000, RR=2.348, 95%CI 1.527-3.610; for ceLM: 4.24% vs. 15.53%, P=0.000, RR=4.147, 95%CI 2.836-6.064) and the live birth rate was significantly lower (for unLM: 49.96% vs. 43.01%, P=0.005, RR=0.756, 95%CI 0.622-0.918; for ceLM: 49.96% vs. 38.59%, P=0.000, RR=0.629, 95%CI 0.512- 0.774) in both unLM and ceLM groups. Women with a previous ceLM were also associated with a higher risk of preterm birth rate (7.21% vs. 11.65%, P=0.001, RR=1.698, 95%CI,1.230-2.345), along with an overall lower birth weight of newborns (both singleton and twins) than gIVF group (for singleton: 3432±533 vs. 3278±617 P=0.004; for twins: 2581±441 vs. 2185±474 P=0.002).
LM also recurred more frequently in the trLM group, and the live birth rate resultantly decreased, however, without statistical significance reached (49.96% vs. 37.50%, P=0.064, Figure Ⅰ ). The pregnancy outcomes in the feLM group were similar to that of gIVF group (Figure Ⅰ ).
In addition, the significantly decreased cumulative live birth rate within one year after occurrence of LM were observed in all LM subgroups compared with gIVF group, possibly due to the overall less transfer cycles and embryos transferred (Table S1 and S2 ).
After adjusting the confounding factors, including maternal age, BMI, basal hormone levels, number of antral follicles, PCOS diagnosis, endometrial thickness on hCG trigger day and reproductive history, the results of binary logistic analysis demonstrated that a history of unexplained LM or LM resulted from cervical factor had a significant correlation with the poor pregnancy outcomes after subsequent embryo transfer, as shown in Table Ⅲ . LM resulted from trauma factor also displayed a strong association with the recurrence LM in the subsequent pregnancy (4.24% vs. 18.42%, P=0.000, RR=5.094, 95%CI, 2.198-11.803).