Other Causes
Hormonal rhinitis or pregnancy-induced rhinitis is one of the most common causes of postnasal drip during pregnancy. Signs and symptoms tend to start during the second trimester. They would last until delivery and then resolve on their own. In some people, hormonal rhinitis could happen with hypothyroidism or the intake of birth control pills.
Another possible cause is rhinitis medicamentosa. It is a form of congestion and runny nose that happens when people take specific medications excessively. When the bodies adapt to the drugs, they will need more. If this cycle is disrupted, it might lead to serious postnasal drip. [5]
