To bathe or not to bathe

Ok so yesterday I had some dull pains in one side of my belly and going into my back so my feiance drew me a bath in hopes that it would help me, well almost imedietly my sister in law informed me that when she was pregnant and in her third trimester the doctors told her not to take baths because it could put her in labor, has anyone Hurd of this before? Is it ok to still take baths to relieve my aches and pains because I do not like meds