I'm not a professional, but I would say that pregnancy is definitely not a time to do anything stressful on the body, but the alkilnity and ph of the body might be a PASSIVE (not strenuous) and safe way of addressing your health at this time. Check out www.genderlabs.com/boy_alkilinity.shtml That site stresses the importance of alkilinity for pregnant health.
(it's just an idea, but you might also have to give your body time to rebuild itself after Antibiotics ).