Have had migraines with auras for years now, after having second child auras are extreme, is this normal?

Very Common. Pregnancy can cause profound exacerbation of migraine symptoms.
Possibly. Many women experience a change in their migraine features with hormonal fluctuation. There is no greater hormonal fluctuation (besides menopause) than pregnancy. Some women have complete cessation of migraines with pregnancy, while others can have severe worsening of the type and severity of migraine. If there's ever a change in your "usual" headache symptoms your neurologist should be involved.