Frozen sperm just as effective as fresh for insemination treatments

Published 05 July 2022

The largest study of its kind has found ‘no detrimental effect of cryopreservation’ on treatment outcomes from IUI when compared with those from fresh samples.

Patients having IUI for fertility treatment can be reassured that the use of cryopreserved sperm instead of fresh is not associated with any inferior outcomes. The largest study of its kind, whose results were presented at the 38th annual meeting of ESHRE, found no difference in pregnancy rates between cycles using cryopreserved or fresh sperm samples. The results of the study, presented today by Dr Panagiotis Cherouveim from Massachusetts General Hospital and Harvard Medical School, USA, were based on an analysis of 5335 IUI cycles performed at this single centre between 2004 and 2021. ‘Patients undergoing IUI should be counselled about the non-inferiority of frozen sperm,’ said Cherouveim.

However, despite widespread use of sperm freezing, there are concerns among patients that cryopreservation might reduce the viability of the frozen/thawed sperm cells, affecting their motility, structure and DNA content. ‘Contemporary data are still scarce,’ said Cherouveim.

The study analysed a range of outcomes following IUI treatments with either fresh (n = 3464) or frozen sperm (n = 1871), which included a positive pregnancy test, clinical pregnancy, and miscarriage rate. The study also controlled for the type of ovarian stimulation either given or not given to women before their IUI treatment.

Results after adjustments for confounding variables found similar clinical pregnancy rates between the fresh and frozen sperm groups – although there were some minor differences noted in a sub-group of patients having ovarian stimulation with oral medications (clomiphene citrate or letrozole). However, when the analysis was limited to a first cycle of treatment, these differences were no longer evident. ‘No detrimental effect of sperm cryopreservation on IUI outcomes was noted,’ said Cherouveim

He added following a question from the floor that the majority of cryopreserved sperm samples in this study came from anonymous donors, which because of their screening might bias the results. However, said Cherouveim, this reflects the everyday practice of most fertility centres – and this was a study to test treatments, rather than the technology. Nevertherless, despite the widespread use of sperm cryopreservation and regulatory requirements, he said that patients often express concern over the duration of freezing or that the sample only represents a portion of the ejaculate. However, he said, this study provides largely reassuring data on the non-inferiority of frozen sperm use.

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