What is rhinitis of pregnancy?

Hormanal changes: Yep... It's the hormones. Unfortunately, the changes in hormone levels can cause significant nasal stuffiness and engorgement of the nasal trubinates. Topical afrin is effective but you don't want to use more than several days at a time.

Could be allergy: Yes, women can develop allergies while pregnant. In fact, women with allergies who become pregnant have about a 30% chance of it getting worse, staying the same, or getting better. Now, nasal congestion alone in pregnancy may be due to increased blood volume, and should go away after delivery. Allergy, however, is going to stay.