Chronic scrotal hypothermia: results in 90 infertile couples.
Plain-language summary
This study looked at whether cooling the testicles every day helps men whose couples had been unable to conceive. It followed 64 men who had subfertile semen and a raised testicular temperature, all of them in marriages of two years or more without a pregnancy where the wife had been judged fertile. They wore a cooling device daily for at least 16 weeks. Semen was scored using the motile oval index, a single number combining sperm count, movement and normal shape, which the authors use because it tracks the chance of a pregnancy. Two thirds of the men improved on at least one semen measure. Among the 21 men who began with a higher index, 11 produced a pregnancy. A separate group of 20 men who wore the device for under two weeks or not at all produced one pregnancy between them, and the paper does not report what those men's starting index was, so the two rates are not a like-for-like comparison.
Key findings
- 42 of the 64 men (65.6%) improved on at least one semen measure while using the cooling device.
- Of 21 men who started with a motile oval index above 4.8 million per mL, 11 (52.4%) produced a pregnancy.
- Men who started from a lower index did not do as well.
- Separately, of 20 men who met the entry criteria but wore the device for under two weeks or not at all and had no other treatment, 1 (5.0%) produced a pregnancy. The abstract does not give this group's starting index, so it is not a like-for-like comparison with the 52.4%.
- Six men who had no sperm at all in the semen, for reasons other than a blockage, saw no change on the device.
- The average time on cooling before a missed period was 4.2 months.
How to analyze the study yourself
- Study type
- Cohort studies track outcomes in a group receiving an intervention, but without random assignment, other factors could influence the results.
- Population
- Men with poor semen quality and higher testicular temperature in long-term infertile marriages (female partners confirmed fertile).
- Funding
- Not reported
- Takeaway
- In men with subfertile semen and a raised testicular temperature, whose couples had not conceived in two years or more, this study found that a cooling device worn daily improved at least one semen measure in two thirds of them, and that 11 of the 21 men who started from a better semen score went on to a pregnancy. Only 1 of 20 men who barely used the device or did not use it at all did, though the paper does not say what those men's semen scores were to begin with, so treat that gap as a gap. The six men who started with no sperm at all saw no change in their semen. If you are trying to conceive, it is worth keeping your testicles cool.