I took a hot bath this morning only for 5 minutes. i'm 19 weeks 1 day pregnant. my belly was little pink when i got out. did i cause any harm?

Not likely: Patients who are pregnant can take baths. Baths are soothing in pregnancy and can relieve pressure and pain in one's back. Ideally you should take a warm bath, not a hot one. You likely didn't cause any harm in the short time you were in the bath. A hot tub is too hot for pregnant women. If you're skin is turning pink, that's a little too hot. Next time add a little more cold water :-).