Hi welcome to Healthcare magic forum. You are using steroids for bronchial asthma. Steroids have suppression property over allergy , inflammation and ovulation as well. So to conceive you should get treatment under the supervision of a infertility clinic, and a chest physician.
You had already a child you don't have any problem with conception but only problem is with steroids. chest physician will look after this problem and try to controle asthma with out steroids.
Besides i advise you some non medical procedures . Diversion procedures, asthma is also dependent on tension, though not produced it will increase with tension. Tension can supress the ovulation and conception as well. So try to practice yoga, meditation, reading books, and hearing music.
Diet procedures, take more of green leafy vegetables, pulses, sprouts, milk, egg , meat, and dry fruits. these will increase the blood, general health, resistance against asthma, and stamina.
Strictly avoid taking ice water, ice cream, cooldrinks, fruits, juices, fish and other sea foods to reduce the intensity of asthma. Wishing for a beautiful recovery and thanks for calling.