MILAN, Italy — Good news for couples using fertility treatments to conceive a baby. In the largest study to date, researchers have shown that frozen sperm works just as well as fresh sperm for insemination and pregnancy.
“Patients undergoing IUI should be counseled about the non-inferiority of frozen sperm,” says Dr. Panagiotis Cherouveim, a researcher at Massachusetts General Hospital and Harvard Medical School, in a media release.
Cryopreservation is the most favorable choice for storing sperm, and in some places, a requirement for using donor samples. The sperm can stay frozen for up to six months and gives fertility doctors time to screen for infections before use.
Despite its use, there are some concerns that cryopreservation can reduce the viability of frozen and thawed sperm cells. Doing so could lead to the reduction of a sperm’s motility, structure, and DNA content.
“Contemporary data from intrauterine insemination cycles are still scarce,” Dr. Cherouveim explains.
What are the benefits of using cryopreserved sperm?
The team analyzed 5,335 intrauterine insemination cycles performed at Dr. Cherouveim’s center between 2004 and 2021. The analysis looked at pregnancy outcomes and miscarriage rates when using fresh versus frozen sperm. The study did control for any type of ovarian stimulation given to women before their insemination treatment.
There was no difference in pregnancy rates using fresh or frozen samples. The only difference seemed to be the time it took to receive a positive pregnancy result. People using frozen sperm took longer to get pregnant than those who used fresh sperm.
“Although, specific subgroups might benefit from fresh sperm utilization and time-to-pregnancy might be shorter with fresh than frozen sperm, patients should be counseled about the non-inferiority of frozen sperm. No detrimental effect of sperm cryopreservation on IUI outcomes was noted,” the study author reports.
“The fact that our data did not reveal any significant difference in success between the utilization of fresh ejaculated and frozen sperm, except in a subgroup of patients given oral ovulation-inducing agents, is very reassuring to all involved,” Cherouveim adds.
The findings that frozen sperm is not inferior to fresh sperm could be especially reassuring for single mothers by choice and same-sex couples who may use a cryopreserved sperm sample to get pregnant.
Another upside is that using frozen sperm will likely not face any regulatory obstacles and could help protect the health of babies by screening for any sperm issues.
“Quarantine and screening requirements are in line with safety principles, and are in place to protect patients. The upside of their implementation far outweighs any downsides,” the researcher concludes.
Dr. Cherouveim presented the findings at the 38th annual meeting of the European Society of Human Reproduction ad Embryology.