Calcium Ionophore A23187 treatment to rescue unfertilized oocytes: a prospective randomized analysis of sibling oocytes


      Research question

      Can 1-day old human unfertilized oocytes activate and blastulate after exposure to calcium ionophore (Ca.I) A23187?


      Prospective randomized trial analysis of sibling oocytes. Seventy unfertilized sibling oocytes from 24 couples were randomly split into two groups. In the treatment group, 35 oocytes were cultured with 5-µM Ca.I A23187 for 10 min, washed and cultured until day 6 of development (D+6). The remaining 35 oocytes (control group) were similarly cultured until D+6. Activation, cleavage and blastulation rates were compared between the two groups.


      Comparable activation rates were observed in the oocytes incubated with Ca.I A23187 and in the control group (11.4% versus 17.1%; P = 0.49). The cleavage rate observed was 45.7% in both groups. None of the embryos reached blastocyst stage.


      Activation and cleavage can occur in unfertilized oocytes after the diagnosis of failure to fertilize. Unfortunately, the prevalence of activation is not affected by exposure to Ca.I A23187. Additionally, these embryos have no tangible reproductive potential as they arrest before reaching the blastocyst stage.


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      Dr Esbert is an ESHRE-accredited senior embryologyst currently working as embryologist and research scientist at IVIRMA New Jersey. She graduated, and received her master's and PhD degrees, from the Universitat Autònoma de Barcelona. Her main research interest is male infertility and IVF.
      Key message
      Calcium Ionophore A23187 is not successful in triggering activation of unfertilized human oocytes the day after intracytoplasmic sperm injection. Its use is not recommended for that purpose.