The largest study of its kind has found no difference in pregnancy rates between intrauterine insemination (IUI) cycles using fresh or frozen sperm.
The research was presented at the annual meeting of the European Society of Human Reproduction and Embryology by Dr Panagiotis Cherouveim from Massachusetts General Hospital and Harvard Medical School.
'The fact that our data did not reveal any significant difference in success between the utilisation of fresh ejaculated and frozen sperm, except in a subgroup of patients given oral ovulation-inducing agents, is very reassuring to all involved,' said Dr Cherouveim. 'No detrimental effect of sperm cryopreservation on IUI outcomes was noted.'
The study looked at outcomes from 5335 IUI treatments that took place from 2004-2021. Overall there was no significant difference in pregnancy rates, but some differences were observed in patients who had ovarian stimulation prior to insemination, versus those who did not.
'Although, specific subgroups might benefit from fresh sperm utilisation and time-to-pregnancy might be shorter with fresh than frozen sperm, patients should be counselled about the non-inferiority of frozen sperm,' said Dr Cherouveim.
One limitation of the study is that most of the frozen sperm came from anonymous donors, who tend on average to be younger, and healthier than the partners providing fresh sperm, and usually have good quality sperm.
'On the face of it, it's reassuring to find that there is no material difference in the success of fresh or frozen sperm during an IUI procedure,' andrologist Professor Allan Pacey from the University of Sheffield told BioNews. 'However, in this study, the frozen sperm was from donors who are highly selected men precisely because their sperm can survive the freezing process. Therefore, is there really any surprise that the authors found no difference?'