Many women suffer from nosebleeds during their pregnancy. This has to do with two factors:
First, this is due to the hormone progesterone. Because of this hormone, your blood vessels become thinner and lighter.
The second factor that plays is the fact that you have more blood in your body during pregnancy.
These nosebleeds are usually innocent, but very inconvenient for the sufferer.
Nosebleeds can occur very early in pregnancy. It is therefore characterized as one of the pregnancy symptoms. A similar pregnancy problem is bleeding gums during brushing, which is similarly caused by progesterone and higher blood volume and pressure during pregnancy.
From angelababy In Q&A