Pregnancy is often accompanied by nasal congestion, but external swelling is also possible although less common. Noses in pregnancy are frequently described as looking wider, and this may be due to increased size of the fibrofatty tissue within the nose. Some ethnicities, including African-Americans, have more fibrofatty tissue beneath the skin and between the cartilages of the nasal tip, and thus have a greater propensity to widen during pregnancy. This generally resolves after childbirth, but not always.
Nasal swelling can result from the immediate postoperative period, usually first month, from repeated trauma, or from allergic reactions. The skin and soft tissue envelope is usually the layer resulting in swelling. Pregnancy can be associated with weight gain which can marginally translate into edema in the nasal layer, but it shouldn't cause significant change in the aesthetic of the nose.