No differences were identified between IVF cycles taking place before and after the patients received the Pfizer COVID-19 vaccine.
In an observational study, the characteristics of the ovarian stimulation cycle, and outcome in terms of the proportion of high-quality embryos, were compared across two successive IVF cycles: pre- and post-vaccination.
Professor Raoul Orvieto, who led the study at the Sheba Medical Centre in Tel Hashomer, Israel, told the Jerusalem Post: 'Comparing two IVF cycles was the best way to see if the vaccine would have any impact in terms of number of eggs or any other factors. It did not.'
The 36 couples in the study were all undergoing fertility treatment prior to receiving two doses of the Pfizer mRNA COVID-19 vaccination. Both partners received the vaccine, with the subsequent IVF treatment cycle taking place between 7-85 days post-vaccination.
Published in Reproductive Biology and Endocrinology, the study observed no differences in cycle characteristics including length of stimulation, and peak estradiol and progesterone levels. Further, no differences were observed in the number of oocytes (immature egg cells) retrieved, fertilisation rate, or the proportion of high-quality embryos formed.
Professor Orvieto and his colleagues previously published results on the effect of SARS-CoV-2 infection on outcomes of patients undergoing IVF treatment. There was no decrease in patients' performance or ovarian reserve in IVF cycles following recovery from COVID-19, however, a reduction in the proportion of high-quality embryos was seen.
'We decided to carry out this research because many people are scared of the possible effects of the vaccines on fertility,' said Professor Orvieto. 'I hope this will help fight misconceptions about the vaccine.'
Semen analysis was also included in the study, with no effect observed in key measures including sperm concentration and total motile sperm count. These observations support the findings of a separate study on male fertility published recently, which compared sperm samples of 45 participants taken before and after receiving two doses of either the Pfizer or Moderna vaccine (see BioNews 1100).
Professor Orvieto said 'We are the first to demonstrate and publish that the vaccine has no effect on both male and female fertility.'
The authors note that validation of their observations is required by larger studies with longer follow-up times. 'However, I do not expect any different results,' said Professor Orvieto.