Is it ok to take a probiotic while pregnant?

Uncertain.: No research has proven safety for probiotics during pregnancy - although they are considered generally safe. They do change the flora of your digestive tract, though, and could affect your immune system, your vaginal flora and thus modify your risk for preterm birth and aberrant fetal growth. Fetal effects indirectly via maternal microbiome changes may be expected as well. Avoid for now.

Yes: Probiotics are safe during pregnancy.