Consult your doctor if you notice any of these warning signs: 1. Vomiting and nausea, can be a normal first trimester symptom. But if you have persistent nausea and vomiting several times a day, can’t keep any fluids down for 12 hours, or are lightheaded from vomiting, consult your doctor. It may be a condition called hyperemesis gravidarum, which can cause problems such as weight loss, low birth weight, and dehydration.�� 2. Headaches during pregnancy can be caused by hormonal changes, stress,