Well tonight (I'm 15w5d) I took a hot bath, and I mean hot. 104. I needed it. My lower back is in so much pain. My idea was to get in and out of the bath every five minutes to allow my body to cool down as to not harm baby. And this is what I found. 

In a matter of minutes (10ish) the bath cooled down to 100 degrees. My body temp and skin temp never rose above 98. After the first couple times of getting out, I gave up and laid there, for probably 20 minutes, with the hot water running on again. Like I said, I needed the heat. The entire time I took a bath over 100 degrees, stayed in for an extended period of time, my skin and core temp never rose above normal. I kept water by my side to sip. I even got a little sweaty at times (as if I were in the sun) and still, my skin and core temp never raised. 

After tonight, I plan on taking hot baths as I used to before; without fear of harming my baby. I'll keep the thermometer and water by my side, check my temp a few times, but I'm going to focus on relaxation. 

I think over time women get increasingly more paranoid about harming their unborn, when the reality is our bodies are the perfect place for them. They can't regulate temperate, but we can for them. I just left the bath, and my temperature is a perfect 98.6. 

Rest assured ladies, your babies are safe. Now go relax in that hot bath! We are obviously not all the same, but hopefully this encourages one or two of you to trust your body, and forgo the recommended 98 degree bath, take it up a degree or two so you actually get a benefit from it. Cause let's be honest; that's freaking cold. Keep the thermometer by your side, check your knee bend for skin temp and mouth for normal temp! Good luck to you all :)