For example, taking tetracycline during pregnancy can cause permanent staining of your unborn baby's teeth. Aspirin can cause life-threatening asthma episodes if you are sensitive to it. Antihistamines' effects on your unborn child are unknown. Talk to your doctor before you take them. It could cause your baby to be born with jaundice.
Decongestants can potentially increase the heart rate of both mother and child.
Continue your regular allergy shots. If you take regular allergy shots and have no reaction to them, you'll need to continue them during your pregnancy. As always, your allergist will monitor your dose. Don't start allergy shots for the first time after you become pregnant. The dose should not be increased during pregnancy, but maintenance immunotherapy is safe and may allow you to require less oral medications.