Male fertility is adversely affected by using a hot tub with high water temperatures, and they are not recommended if trying for a baby. Although there is no evidence it affects female fertility, it could harm the unborn baby, so hot tubs are not recommended for couples trying to conceive.
Trying for a baby can be a stressful time, especially if you are not getting pregnant as quickly as you wanted to. You might think that relaxing in the hot tub might help reduce this stress, but you need to be careful as hot tubs may adversely affect your fertility, or worse, be harmful to your unborn baby.
Declaimer: I am not a doctor. I am a radiographer, but I have used my access to medical journals to write this article. If you have any questions about fertility or looking after your unborn child, please speak directly to your healthcare professional.
Can hot tub use affect fertility in men?
There are many articles that evidence how soaking in hot water can affect the fertility of males. This effect is because sperm production takes place in the testicles, and the optimum temperature for this to happen is about three degrees cooler than body temperature.
Infertility caused by heat is generally temporary. Sperm takes about three months to mature, so they should be back to normal after three months. General advice on increasing fertility is to stop smoking and drinking and to maintain a healthy weight.
Can men safely use the hot tub if the water temperature is lowered?
In theory, sitting in a refreshing hot tub would not affect fertility and would be considered safe. However, cold hot tubs are generally not relaxing or enjoyable!
In the summer I sometimes lower the temperature of the hot tub so I can enjoy the experience during the heat of the day, but in the evening the low water temperature is not fun.
Sperm counts and fertility
There is a direct correlation between sperm count and fertility. If you are struggling to conceive, it may be a good idea to check sperm count. Many family clinics offer this service, but it can be expensive, and some people find the idea of talking about this very embarrassing.
You can now purchase DIY home sperm kits from Amazon which are delivered in the standard Amazon box, so are discrete. They claim to be as accurate as hospital tests, which may be true but hospitals will test for other anomalies, not just sperm numbers.
The reason I think home testing kits are a good idea is that it starts a conversation, and this must be a good thing. If you know that your sperm count is low, then you can look at changing aspects of your lifestyle to improve it. And yes, it may mean cutting hot tubs from your life temporarily!!
For further advice on becoming pregnant check out webMD.
Can hot tub use affect female fertility?
Unlike men, female reproductive organs are internal. Unless you are very sick, the body does a fantastic job of maintaining core temperature stability. Therefore, hot tubbing is unlikely to affect female fertility unless you stay in there too long and severely overheat. Hot tub use may even help by destressing you and helping you sleep better.
However, when my wife and I decided to try for a baby, we both decided to stop using the hot tub because of the next point.
Hot tub use – is there a risk to the unborn baby?
Yes. There is much evidence in the literature that increasing body temperature increases the risk of congenital disabilities by as much as 100%. When the foetus’s brain and spine are forming, it is particularly sensitive to temperature change.
I used a hot tub before I knew I was pregnant – will my baby be okay!
Around half of pregnancies are unplanned, so many mothers-to-be were not following recommended advice like avoiding alcohol etc. So there will invariably be some that used a hot tub, and they really should not worry as the risk that something has gone wrong is very small.
Now to put the risk into perspective, the chance of baby spinal defects in the general population is 1/1000, so if you use the hot tub, it is now 2/1000 or 1/500, which means that the probability of your child having a problem is very slim.
Is it safe to use a hot tub while pregnant?

After the first trimester, the babies’ spinal cord and brain are formed, and there is no evidence, I could find, to suggest sensible hot tub use from week 12 was harmful to the baby. As long as the mummy-to-be follows safety precautions, using hot tubs could be a fabulous way to unwind and spend time with the equally excited father-to-be!!
Precautions to take when using a hot tub while pregnant (12weeks +)
- Make sure you stay hydrated – take a bottle of water in the hot tub with you.
- Keep the hot tub water lower than body temperature (below 100 degrees Fahrenheit).
- Keep your sessions below 20min and leave if you are feeling too hot
- Make sure you are not alone. The risk of fainting is higher when you are pregnant, so please make sure you are with someone.
- run the jets on low power and make sure they are not directly aimed at you tummy (there is no evidence for this point BTW, but it seems sensible!!)
Aromatherapy can add to a relaxing hot tub experience. This article I wrote details how to use aromatherapy without damaging the hot tub or making the water unsafe!
How to maintain a hot tub that is not being used?
So you have decided to refrain from using a hot tub until you are blessed with a pregnancy. Now if you are lucky, this may be a few weeks, but the majority of people this takes a lot longer. 45% of couples would have conceived within three months, 65% within six months, 85% within a year and 93% within 18 months. These numbers are based on a women younger than 37, with no fertility problems.
So your hot tub may be sitting idle for some time… What are your options?
Option 1: Drain the hot tub
When you drain a hot tub, you must make sure that the pipes are also free from water to avoid damage from ice formation in winter. Most people use a sump pump to drain their hot tub as this speeds up the process, but it will not remove the water from the pipes.
To remove the water from the pipework, you will need to open the spa drain and let gravity remove as much water as possible. Now there may be some water left in the pipework or pumps, but the chance of ice damage is reduced.
If you were expecting a harsh winter, you could place a thermostatic tubular heater in the hot tub’s cabinet. We use this technique around our boat’s engine, and it works very well. The heaters are low wattage, so it will not cost much to run.
Option 2: Leave the hot tub running but lower the water temperature.
Leaving the hot tub on is my preferred option because it keeps the hot tub ticking over, which is what they are designed to do. Lowering the temperature will save on the cost of running the hot tub while preventing any winter damage at the same time.
You will still need to add sanitizer, but you will find the amount of chemical required will be significantly reduced. As long as the hot tub is covered, you will not need to change the filter as often as no contaminants will be getting into the water.
Finally…
If you are trying for a baby, I wish you all the luck in the world, and hopefully, you will be blessed quickly and then able to use the hot tub again soon!!
Have a fabulous day,
Brendan
Ps. If you think I have missed anything in this article let me know and I will update it.