Failure to detect DNA in blastocoel fluid is associated with a higher live birth rate in both PGT-A and conventional IVF/ICSI cycles.

Study Question: Is the presence of DNA in the blastocoel fluid (BF) of expanded blastocysts, assessed by whole genome amplification (WGA), associated with the clinical outcome at the first transfer?

Summary Answer: At the first transfer, blastocysts with negative BF-WGA have more chance to implant and to develop to term than those with positive BF-WGA results, both in preimplantation genetic testing for aneuploidies (PGT-A) cycles (where only euploid blastocysts resulting from the chromosomal analysis of trophectoderm (TE) biopsies were transferred) and in IVF/ICSI conventional cycles.

What Is Known Already: Retrospective studies conducted in patients undergoing PGT-A have shown that the incidence of negative BF-WGA was significantly higher in TE-euploid blastocysts than in TE-aneuploid blastocysts. In addition, after the transfer of TE-euploid blastocysts, the ongoing clinical pregnancy rate was significantly higher in the group with negative BF-WGA compared with those with positive BF-WGA.

Birefringence properties of human immotile spermatozoa and ICSI outcome.

Research Question: In sperm samples with complete asthenozoospermia, pregnancies are achieved by intracytoplasmic sperm injection (ICSI), but this condition has a negative impact on fertilization and embryo development owing to the difficulty of identifying viable cells for oocyte injection. Is the selection of sperm cells with head birefringence properties under polarizing light a successful strategy to identify viable spermatozoa?

Design: This study included 192 ICSI cycles with complete asthenozoospermia (83 ejaculated and 109 testicular samples) performed under polarized light. Two types of sperm head birefringence were distinguished: partial (presumably reacted spermatozoa) and total (presumably intact acrosome).

IVF Lite: a smart IVF programme based on mild ovarian stimulation for good prognosis patients.

Research Question: The IVF Lite programme is based on mild ovarian stimulation including up to three fresh/frozen embryo transfers within 12 months. Is it effective and safe in good prognosis patients?

Design: Single-centre prospective study on infertile patients at their first IVF attempt (female age ≤38 years, anti-Müllerian hormone concentrations >1.5 ng/ml and/or FSH ≤10 mIU/ml).

Oocyte donation: not all oocyte cryobanks are the same.

Research Question: Is the efficacy of imported vitrified oocyte donation affected by the cryobank of origin?

Design: Longitudinal cohort study, including 249 completed oocyte warming cycles from 200 recipients (January 2016-July 2020). No severe male factor was included. Vitrified oocytes were provided by three Spanish cryobanks.