The autonomic nervous system, which controls involuntary bodily functions like heart rate and digestion, undergoes changes during pregnancy. This can lead to "vasomotor instability," where the blood vessels in the nose overreact to stimuli. This means the nasal blood vessels may swell unpredictably, leading to intermittent congestion or a persistently runny nose.
Pregnancy rhinitis typically begins in the second or third trimester, as hormone levels and blood volume reach their peak. It usually resolves on its own within two weeks after delivery as hormone levels and blood volume return to normal. what causes pregnancy rhinitis
In addition to hormonal changes, other factors may contribute to pregnancy rhinitis: The autonomic nervous system
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