7wks pregnant, is prednisone safe for treating my 1st time hives 3 days going, benadryl (diphenhydramine) seems to calm it, appears after 8 hrs effect, is this safe?

Not really safe: Studies suggest that there's a small increased risk of oral clefts when taking Prednisone in the first trimester. An oral cleft happens when the lip or palate (roof of the mouth) does not fully close during development. Before you take prednisone, discuss other options with your healthcare provider. There are other medicines available that may be safer and still keep your hives under control.