O-174 Individualized versus standard FSH dosing in predicted poor responders: an RCT

Abstract Study question Is there a difference in fertility outcomes between individualized or standard FSH dosing in women scheduled for IVF with an expected poor response? Summary answer In predicted poor responders (AFC<10) undergoing IVF/ICSI, individualized FSH dosing does not improve ongoing pregnancy rates as compared to a standard FSH dose. What is known already Poor responders usually lead to many detrimental effects on IVF outcomes due to low oocyte number and quality which in turn result in low pregnancy outcomes and an increased chance of cycle cancellation. Clinicians often individualize the FSH dose using ovarian reserve tests (ORT), including antral follicle count (AFC), basal FSH (bFSH), and anti-Mullerian hormone (AMH). However, it is unclear whether individualized FSH dosing improves clinical outcomes. Study design, size, duration Between March 2019 and April 2020, we performed a single-center, parallel, open-label RCT in women with an AFC<10. A total of 661 women were randomized either to start FSH dosing at 300IU/225IU or 150IU. The primary outcome was live birth attributable to the first ART cycle within 18 months of randomization. In this abstract, we report ongoing pregnancy rates. Live birth date will be available at the meeting. Participants/materials, setting, methods Women referred for their first IVF/ICSI cycle, <43 years of age, AFC<10 were approached. A total of 328 women were allocated to the individualized group and 333 women were allocated to the standard group. In the individualized group, women with AFC 1-6 were assigned to 300IU/day (n = 122), while women with AFC 7-9 were assigned to 225IU/day (n = 206). In the standard group, women were assigned 150IU/day. Outcomes were evaluated from an intention-to-treat perspective. Main results and the role of chance For ongoing pregnancy rate attributable to the first ART cycle for individualized versus standard dosing was comparable [52.44% vs 46.25%, relative risk (RR): 1.29 (95%CI, 0.94-1.74), P = 0.11]. Biochemical pregnancy rate [62.50% vs 62.16%, RR: 1.01 (95%CI, 0.74-1.39), P = 0.929], clinical pregnancy rate [59.45% vs 58.86%, RR: 1.02 (95%CI, 0.75-1.40), P = 0.877] and multiple pregnancy rate [5.18% vs 5.12%, RR: 1.01 (95%CI, 0.51-2.02), P = 0.971] also did not differ between individualized and standard dosing. There are 24 women who are ongoing pregnancy but do not reach live birth in the completed embryo transfer cycle. The individualized group reported less poor response (31.1% vs 48.7%: P < 0.001), more obtained oocytes (6.80 ± 3.85 vs 5.28 ± 3.22; P < 0.001), less embryos (3.76 ± 2.70 vs 3.16 ± 2.42; P = 0.004), and less good quality embryos (2.61 ± 2.29 vs 2.21 ± 2.05; P = 0.018). When outcomes were compared over the first embryo transfer, ongoing pregnancy rates were 39.0% (128/328) versus 37.2% (124/333), respectively [RR:1.08 (95%CI, 0.79-1.48), P = 0.636], without differences in the other outcomes. There are 7 women who are ongoing pregnancy but do not reach live birth in the first embryo transfer cycle. Limitations, reasons for caution Due to the open-label character, potential selective canceling and small dose adjustments of standard dosing were allowed. This abstract reports on ongoing pregnancy. At the meeting, we will present live birth rates. Wider implications of the findings In women with predicted poor response, an increased dose does not increase ongoing pregnancy rates. A standard dose of 150IU/day is recommended in these women. Trial registration number ChiCTR1900021944