its common because our body changes during pregnancy...everything goes 'haywire'....which also explains why sometimes we hated a particular smell...or we have stuck nose....etc and etc, all kinds of nasal problems.
here is a list for you:
How to prevent nose bleeds
Avoid drying medications like nasal sprays and decongestants. You should consult your doctor about any medications that you take during your pregnancy.
Avoid being around smoke or heavy perfumes that might irritate your nose.
Use a humidifier. Humidifiers help to keep the air in the room moist. This can help to clear up congestion and keep your nasal passages from drying out.
If your nose feels congested, dont’t pick your nose or blow your nose forcefully. Try taking a steamy shower to loosen up the congestion or rinsing your nose with saline drops. (Do not use medicated drops without consulting your doctor).
Keep yourself hydrated. Drink plenty of fluids to keep your membranes from drying out.
extracted from Nose Bleeds During Pregnancy