Alteration of final maturation and laboratory techniques in low responders

The number and quality of embryos generated from the limited number of oocytes retrieved from low responders are important aspects of infertility treatment for these patients. This article focuses on 5 aspects relating to final maturation and laboratory techniques: follicular size at trigger, dual trigger, artificial oocyte activation (AOA), blastocyst transfer, and the role of preimplantation genetic testing for aneuploidy (PGT-A). There is lack of data regarding the role of follicular size, specifically in low-responder patients, but consideration should be given to using broader follicular size criteria when retrieving oocytes in this patient group. Use of dual trigger seems to be a good strategy in low-responder patients on the basis of initial evidence. Use of AOA with calcium ionophore may improve fertilization, embryonic development, and outcomes in cases with previous developmental problems. There is lack of data for low responders, but this promising technique deserves further study. In unselected patients, clinical trial data on blastocyst transfer are conflicting, and no high-quality studies have evaluated whether the live birth rate is higher after blastocyst transfer than after cleavage-stage embryo transfer in low responders. Specific evidence for PGT-A in low-responder patients is also lacking. Preimplantation genetic testing for aneuploidy should be considered in POSEIDON group 2 patients, especially those aged >38 years. Overall, applying the limited data available in combination with patient preference and individual patient characteristics will ensure a patient-centered and evidence-based approach that should optimize fertility outcomes for low responders.