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Published on: September 7, 2021
Effect of embryo culture medium pH on live birth rate after IVF/ICSI: a double-blind, multicentre, randomized trial
Nicolas Gatimel1, Lucie Chansel-Debordeaux2, Jessica Zokpe3
1Department of Reproductive Medicine, Paule de Viguier Hospital, University Hospital of Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France; DEFE (Développement Embryonnaire, Fertilité, Environnement), UMR1203, INSERM-Universités Toulouse et Montpellier, Paule de Viguier Hospital, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Research Question:
Does live birth rate differ according to the pH of the embryo culture medium after IVF with intracytoplasmic sperm injection (ICSI)?
Design:
Multicentre, randomized, controlled, double-blind trial conducted in three IVF centres. From ICSI to fresh day-3 embryo transfer, embryos were cultured at a target medium pH either 7.22 ± 0.02 or 7.38 ± 0.02. Overall, 424 women aged 40 years or younger undergoing a first or second fresh ICSI cycle with autologous oocytes were included between October 2020 and November 2023. Recruitment stopped before the planned sample size was reached because of feasibility constraints. Randomization (1:1) occurred on the day of oocyte retrieval. The pH was measured daily using a validated method under routine IVF culture conditions. The primary outcome was live birth rate per oocyte retrieval.
Results:
Embryos from 211 couples were cultured at pH 7.22 ± 0.02 and from 212 couples at pH 7.38 ± 0.02. Baseline characteristics, stimulation parameters and sperm characteristics were comparable between groups. Live birth rate per oocyte retrieval did not differ significantly between culture conditions (29.3% versus 27.0%, OR 1.13, 95% CI 0.72 to 1.75, P = 0.60). No significant differences were observed in fertilization rate, implantation rate, ongoing clinical pregnancy rate, miscarriage rate or embryo morphology.
Conclusions:
Maintaining a strict pH of 7.22 ± 0.02 from day 0 to day 3 after ICSI does not significantly affect live birth rate compared with a pH of 7.38 ± 0.02. Early human embryos effectively adapt to pH variations within this range without affecting live birth rate.
