Is it safe for my husband to use a sauna if we are trying to conceive?
There are several things that your husband can do when you are trying to conceive to help keep his sperm count up. For example, tell him to hang loose. Have your partner trade in his tighty-whiteys for boxers about two months before you try and conceive to keep his testicles cool and unrestricted. Although they may look cute, tight quarters and overheating can actually cause his sperm count to drop. For that same reason, have him resist the urge to dip into a hot tub or sauna at the gym.
Hot showers should not lower the sperm count. The body temperature does not usually increase with a shower, though it may increase with a sauna or a long hot tub stay. So those are not suggested when you actively TTC. Please remember that it takes sperms 10-11 weeks to be produced, so anything that happens today will affect the count potentially for the next three or so months.