Conditional and cumulative live birth rates after blastocyst transfer

Objective: We aimed to investigate live birth rate (LBR), cumulative live birth rate (CLBR) for consecutive fresh and frozen-thawed in vitro fertilization (IVF) cycles, and CLBR after an entire IVF programme involving multiple ovarian stimulations using blastocyst transfer only. Study design: From January 1 st 2014 to December 31 st 2018, we included women aged 18–45 years who initiated IVF or intracytoplasmic sperm injection at Aagaard Fertility Clinic, Denmark. The primary outcome was live birth, and secondary outcomes were a positive hCG blood test and ongoing pregnancy confirmed by ultrasonography. All proportions were estimated for initiated and transferred cycles with 95 % confidence intervals (CI). We used a conservative strategy, assuming that none of the women who did not return for further treatments had a live birth. Results: 871 women contributed 2236 initiated/1670 transferred fresh and/or frozen-thawed cycles. LBRs for first fresh cycles were 22.8 % (95 %-CI: 19.8−26.0) and 35.7 % (95 %-CI: 31.4−40.2) for initiated and transferred cycles, respectively. LBRs for first frozen-thawed cycles were 30.6 % (95 %-CI: 26.4−35.1) and 31.7 % (95 %-CI: 27.4−36.3) for initiated and transferred cycles, respectively. CLBRs for consecutive cycles were 18.2 % (95 %-CI: 16.2−20.3) for fresh initiated cycles, 29.7 % (95 %-CI: 26.6−32.9) for fresh transferred cycles, 25.5 % (95 %-CI: 22.6−28.5) for frozen-thawed initiated cycles, and 26.4 % (95 %-CI: 23.5−29.6) for frozen-thawed transferred cycles. For 436 women who contributed with an entire IVF programme we found a CLBR of 64.0 % (95 %-CI: 59.3−68.5). Conclusion: Compared to other studies of CLBR after multiple ovarian stimulations using cleavage stage transfer, our study presents a considerable effect in the IVF success rate when using blastocyst transfer only. In a clinical setting, transfer of blastocysts seems to be a viable method.