In my pregnancy book it says the "hot bath" issue with birth defects is that anything that can increase your body temperature by more than 2 degrees is a no go. Thats why spas and saunas are out. As for advice on a hot bath- sometimes a hot bath can be good for relaxing or to ease muscles but it recommends only staying in the bath for about 10 minutes. As far as other water restrictions it says no to water skiing, scuba diving, and diving as they can force water into yur cervix.