Use of Cumulative Live Birth Rate per Total Number of Embryos to Calculate the Success of IVF in Consecutive IVF Cycles in Women Aged ≥35 Years

OBJECTIVE: The use of cumulative live birth rate (CLBR) per ovarian stimulation cycle is proving to be an accurate method to calculate the success of IVF; however, the cycle outcome is closely associated with the number of embryos transferred (ET). Our aim was to report CLBR after IVF according to the number of embryos required to achieve a live birth in women aged ≥35 years, considering age, body mass index (BMI), and ethnicity. METHODS: We conducted a retrospective cohort study including 1344 patients who underwent IVF between January 2013 and June 2016 at the First Affiliated Hospital of Xinjiang Medical University. The cumulative probability of live birth for each couple was estimated using the Kaplan–Meier method, and survival curves were compared according to age, BMI, and ethnicity using the log-rank test. RESULTS: CLBR increased rapidly from 1 to 5 ETs, moderately from 6 to 10 ETs, and slowly thereafter. CLBR was significantly different across 4 categories based on BMI as well as across those based on age; low CLBR was significantly associated with the age of ≥42 years and obesity. CONCLUSION: The association between CLBR and number of ET provides realistic and precise information regarding the success of IVF and can be applied to guide clinicians and patients.