Will Pregnancy Affect Rhinoplasty Results?

Although the nose swells during pregnancy this should completely resolve once your body returns to its baseline state. The nose is typically congested during the pregnancy and feelings of nasal stuffiness are not unusual

It is very common for female patients -- whether they have had rhinoplasty or not -- to experience swelling of the nose during pregnancy. The outside of the nose can look "puffy" and the inside can swell too, causing symptoms of nasal obstruction. Fortunately, these symptoms should resolve after pregnancy without any lasting effects.

Most cosmetic issues related to pregnancy resolve within weeks to months after giving birth. This includes melasma (pigment deposits), vascular marks, swelling of the body/face/feet, hair growth or loss, as well as many other hormonally related changes to the skin and upper airway.
Most of the nasal swelling is internal, not external. This creates nasal obstruction which can be severe and an increase in nose bleeds. Some patients find irrigation with a comercially available nasal saline wash to help decrease their symptoms. Since it is salt water and has no side effects for your or your baby, it is worth a try if you are uncomfortable.
If any problems persist 3-6 months after giving birth, then I would recommend a consultation with the appropriate cosmetic specialist .

The entire face tends to swell in the third trimester of pregnancy, and indeed, the nose will swell too. This will also resolve at the end of the pregnancy.