Topical steroids and certain oral antihistamines are safe in pregnancy :) apart from these two, the only other option is just to spam moisturizers diligently and to avoid scratching (may cause infections). Other things like avoid excessively washing that area, avoid getting a lot of sweat over eczema areas, avoid scented soaps/harsh washes that can irritate and dry out the areas even more.
Eczema flare itself shouldn’t affect the pregnancy per se (unless of course scratch > local superficial infection > systemic infection but low likelihood) but it probably will just make you very uncomfortable... I’d say try a bit of the topical steroids to tide over the acute flare, you’ll feel much better!