B6 says "not intended for use by pregnant women"???

Cassity • Laila 05/15/17, Xander 4/10/18, and Grace 11/06/2019

My baby's heartbeat was low yesterday at my appointment and my OB said it was because my baby is very hungry due to my morning sickness being so bad. She said to get B6 and prescribed me anti nausea meds. I went to take my b6 100mg this morning and it says on the bottle that it's not intended for use by pregnant women. Should I take it or not? I tried to call my OB office to ask but it's Saturday so they're closed