Pregnancy triggers a dramatic increase in blood volume—up to 50% more than pre-pregnancy levels—to nourish the developing fetus.
Unlike infectious or allergic rhinitis (where a virus or allergen is the trigger), pregnancy rhinitis is driven by physiological changes specific to gestation. The exact mechanism is multifactorial, but research points to the following key causes: what causes pregnancy rhinitis
Pregnancy is a state of generalized vasodilation (relaxed blood vessels) to support the uterus and placenta. This affects the nasal vasculature similarly, leading to reduced nasal airflow and a sensation of stuffiness. Pregnancy triggers a dramatic increase in blood volume—up
By the third trimester, a pregnant woman’s total blood volume increases by nearly 50%. This systemic increase puts more pressure on the microvasculature of the nasal mucosa, causing the tissue to engorge and swell, which physically narrows the nasal passages. This affects the nasal vasculature similarly, leading to
Here is a detailed breakdown of what causes pregnancy rhinitis:
Cause Pregnancy Rhinitis (Important Distinctions)