aetiology

Last reviewed 01/2018

  • the definitive cause of pregnancy rhinitis has not been identified
    • various theories on the aetiology of pregnancy rhinitis have been postulated
      • initial hypotheses on the aetiology of pregnancy rhinitis included oestrogen effects, hormone allergy, stress, and increased blood volume with resulting nasal airway resistance
      • study evidence has revealed that levated serum placental growth hormone as well as increased serum house mite IgE in patients with pregnancy rhinitis (1)
        • placental growth hormone
          • after the first trimester of pregnancy the episodic bursts of human growth hormone (hGH) are replaced by a continuous secretion, with rising values of a placental growth hormone variant (PGH)
            • study evidence has shown that serum levels of PGH were significantly higher in the pregnancy rhinitis group throughout pregnancy
            • a 'hormonal rhinitis' has been proposed to occur in acromegaly - PGH may stimulate mucosal growth in a similar way and thereby induce pregnancy rhinitis (1)
      • smoking is a risk factor (2)
        • howevere maternal age, parity, and gender of the child are not associated with increased risk
        • a history of seasonal allergy such as hayfever, asthma, and month of conception have not been found to have a statistically significant impact on incidence of pregnancy rhinitis
      • vasomotor rhinitis, an imbalance in autonomic nervous control of nasal mucosal smooth muscle blood vessels, has also been offered as an aetiology and remains in consideration as a causative or contributing factor
        • given that either oestrogen or emotional stress can initiate vasomotor rhinitis, a synergistic effect is possible, particularly when there is underlying allergic rhinitis

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