Conditional and cumulative live birth rates after blastocyst transfer

Abstract 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 2,236 initiated/1,670 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 frozenthawed 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 cleavagestage 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.