Allergic rhinitis appears to be associated with thromboembolic disease in pregnancy as pregnant females with allergic rhinitis have an increased rate of thromboembolic disease.

A population-based, retrospective cohort study was conducted to find out if allergic rhinitis (AR) improves or worsens at the time of pregnancy and if the rate of thromboembolic (TE) rises or reduces by comparing the rate of TE between AR and non-AR patients.

A total of 55,057 pregnant females were enrolled from a Taiwan database and were segregated into Group 1: With AR before; without AR post child-birth, Group 2: Without AR before; with AR post child-birth, and Group 3: With AR before; with AR post child-birth. A comparison of the rate of TE and venous complications during pregnancy and post 60 days of child-birth was done between AR and non-AR groups.

Compared to non-AR females, females diagnosed with AR prior to and after parturition exhibited higher rates of venous disorders (Odds ratio, OR 1.35) and TE (OR 2.64). The rate was increased in group 3 (OR 4.14) too, in those who underwent cesarean delivery. An elevated rate of venous complications in pregnant females may explain the increase in thromboembolic disease.

In women with AR before childbirth and without AR after childbirth, the rate of TE was not greater compared to non-AR women.  Various methods like appropriate medical therapy and allergen prevention to better  AR symptoms are crucial to prevent thromboembolic development during pregnancy.

In women diagnosed with AR both before and after childbirth, there exists an association between AR and TE. The rate of TE does not seem to elevate if AR is effectively controlled during pregnancy.