What is recommended for treating nausea during pregnancy?

Prevent, diet, meds. First try to prevent nausea by avoiding strong foods and aromas. Eat a cracker each hour while awake with the first before you get out of bed. Ginger, vitamin b6 (25 mg four times a day) "sea bands" help. Motion sickness medications and stronger anti-nausea meds may be prescribed. If severe vomiting occurs it is called hyperemesis gravidarum and may require IV fluids, meds and hospitilization.
Medication and time . Ginger supplements and b6 vitamins help some. Eating frequent small meals helps others. Some need medication like promethazine, Reglan (metoclopramide) or zofran. Most get better by 12-16 weeks.