Live birth rates in the first complete IVF cycle among 20 687 women using a freeze-all strategy.

STUDY QUESTION: What is the chance of having a child following one complete IVF cycle for patients using a freeze-all strategy?

SUMMARY ANSWER: The chance of having a child after the first complete IVF cycle was 50.74% with the freeze-all strategy.

WHAT IS KNOWN ALREADY: Several studies have reported on live birth rates (LBRs) based on only the fresh embryo transfer cycle or fresh and frozen-thawed embryo transfer cycles. However, the LBR using a freeze-all strategy in IVF is unknown.

STUDY DESIGN SIZE AND DURATION: This retrospective cohort study included 20 687 women who started their first IVF cycles using a freeze-all strategy during the period from 1 January 2007, through 31 March 2016, in China.

PARTICIPANTS /MATERIALS, SETTING, METHODS: Data on 20 687 women undergoing their first complete cycles using a freeze-all strategy from 2007 to 2016 were analyzed to estimate LBRs. The LBR in a complete cycle was defined as the chance of a live birth from an ovarian stimulation cycle including all subsequent frozen embryo transfers from this stimulation. The relationship between LBR and number of oocyte was explored.

MAIN RESULTS AND THE ROLE OF CHANCE: The LBR for the first complete cycle was 50.74% for patients using a freeze-all strategy. By age group, the LBR declined from 63.81% for women under 31 years old to 4.71% for women over 40 years old after the first complete cycle. The LBRs improved as the number of oocytes retrieved increased up to 25 in the freeze-all strategy.

LIMITATION AND REASONS FOR CAUTION: This was a retrospective study without a control group. Data on BMI and smoking status were not collected in this database.

WIDER IMPLICATIONS OF THE FINDINGS: Our results showed that 50.74% of patients could achieve a live birth after the first complete cycle via a freeze-all strategy. In addition, the LBRs were positively correlated with the number of oocytes retrieved via the freeze-all strategy. These findings are critical for patients and clinicians in making an informed decision to embark on IVF treatment.

STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from the National Natural Science Foundation of China (NSFC) (31770989 to Y.W.) and the Shanghai Ninth People's Hospital Foundation of China (JYLJ030 to Y.W.). None of the authors have any conflicts of interest to declare.