The answer to your question depends on the organs effected by your seasonal allergies. If your lungs, and you have allergic asthma, most drugs used for the treatment and control are safe for both you and your baby.
If your seasonal allergies are manifest as allergic rhinitis (nasal allergy) the safest drug treatment would probably be with a nasal steroid spray, the major drug effect in the nose, rather than throughout your body, as is the case with drugs taken by mouth.. While most so-called first generation antihistamines (those that commonly cause drowsiness) are deemed to be safe, there is not enough evidence to conclude that the Second Generation (non-sedating) antihistamines are completely safe.
My advice is that, if at all possible, you avoid any systemic drugs (taken by mouth or injection) during the first trimester. My second suggestion is that you not take any drugs, prescription or over-the-counter, during pregnancy without first clearing it with your doctor.
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. Med Help International, Inc. is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.