O-235 Antioxidants in culture media improve ICSI fertilisation rate: results from a randomised controlled trial

Abstract

Study question: Does addition of three antioxidants to G‐Series media during gamete collection, insemination, and embryo culture increase the clinical pregnancy rate from fresh blastocyst transfers? Summary answer: Antioxidants increased the ICSI fertilization rate, and consequently the number of blastocysts utilised, but the clinical pregnancy rate from fresh blastocyst transfers was not affected. What is known already: Supplementation of IVF media with a combination of three antioxidants known as A3 (10 μmol/l acetyl‐L‐Carnitine, 5 μmol/l a‐Lipoic acid and 10 μmol/l N‐acetyl‐L‐cysteine) is beneficial in mouse IVF, embryo culture and cryopreservation, and improves post‐transfer outcomes. Further, in a prospective randomised trial on sibling oocytes, addition of A3 to G‐1/G‐2 media (Vitrolife, Sweden) resulted in more good quality embryos on day 3 (Gardner et al., 2020). The study was not powered to determine the effect of A3 on pregnancy rate, but an increase in ongoing pregnancy rate was observed in women aged 35‐40 years following frozen blastocyst transfer. Study design, size, duration: Single‐centre, prospective randomised controlled trial, superiority study comparing G‐series media (G‐MOPS, G‐IVF and G‐TL (Vitrolife)) with or without the addition of A3 from January 2019 to November 2021. 1482 patients were randomized before egg collection. Patients and their doctors were blinded to the treatment group. The primary endpoint was clinical pregnancy per randomised couple from the fresh transfer of a single blastocyst. Participants/materials, setting, methods: Patients undergoing IVF/ICSI cycles and intending to undergo a fresh transfer of a single blastocyst were recruited. Exclusion criteria were previous participation in the study, freeze‐all cycle, or extraction of sperm from testicular biopsy. 743 patients were randomised to the A3 media, 739 to the control. Main results and the role of chance: Patients randomised to A3 media had significantly higher fertilisation rate per inseminated oocyte (64.4 ± 25.6%) compared to the control (59.2% ± 26.3%, P<0.001). This was more pronounced in patients undergoing ICSI (68.1% ± 24.9% vs 57.9% ± 27.2%, P<0.0001), where the number of cycles with failed fertilisation decreased from 8.0% to 3.9% with A3 media (P<0.05). There was no effect of A3 on fertilisation rate following IVF. Blastocyst development rate was unaffected by A3, but the higher fertilisation rate resulted in more blastocysts available for transfer or cryopreservation per patient in the A3 group (3.06 ± 2.97 vs 2.67 ± 2.60, P<0.01). Clinical pregnancy rate from fresh cycles was not different between the control (26.1%) and A3 media (23.0%; P>0.05; RR 0.88, 95% CI 0.73‐1.05). When patients who did not have a fresh transfer were excluded (due to freeze‐all or no embryo available), there was also no difference between the control (35.8%) and A3 media (32.6%; P>0.05; RR 0.91; 95% CI 0.77‐1.08). Limitations, reasons for caution: This was a single‐centre study, so the effects of A3 supplementation in clinics with different media and protocols are unknown. Detection of fetal heart by ultrasound was the primary endpoint, birth outcomes are currently being investigated. Outcomes of frozen embryo transfers and cumulative pregnancy rates are yet to be determined. Wider implications of the findings: Addition of antioxidants to media during gamete collection, incubation and ICSI can increase fertilisation rate and reduce the frequency of failed fertilization cycles. This results in more blastocysts available for transfer and cryopreservation per egg collection, potentially leading to higher cumulative pregnancy rates.