Is it safe to use a small amount of cortisone cream when pregnant?

Yes, but only a very mild one and very sparingly. I had severe swelling in my legs and feet with my first child and as a result the skin on my feet was very dry (lotions did not help) and the itch nearly drove me mad - doctor said it was ok to use a mild cortisone cream sparingly (I think it was 0.5% I used?)