i had this when carrying my first child and worst of it started at 4 weeks pregnant, it peaked at 12-17 weeks pregnant where i was sick 30 -50 times a day, this led to me vomiting some blood in small amounts, due to bursting blood vessels when retching, and the stomach lining being irritated due to volumes and frequency of
vomiting, if your girlfriend has similar
symptoms it may be worth seeing your gp/ or maternity consultant as this condition can lead to dehydration, if it not these symptoms