Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Blocked nostrils can occur due to causes like swelling in nasal passages, nasal polyps, allergies, sinus infection etc. So first of all the diagnosis is important, As you are pregnant, do not worry your child must be getting enough oxygen. But for avoiding anxiety and other complications you should consult an Emergency room or an ENT Physician and get evaluated and a nasal examination and if needed a sinus x ray can be done but usually x rays are avoided in pregnancy. You can be advised a course of antibiotics like Amoxicillin as it is considered safe in pregnancy and saline nasal irrigation. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Honey Arora