Vitamin K deficiency has been associated with hyperemesis gravidarum (vomiting during pregnancy). This is a very common symptom and it is a good idea to talk to your doctor about supplementing with Vitamin K if you are experiencing these symptoms…particularly if they are severe. However, be aware that if you have any clotting factor problems then you need to know which clotting factor is effected and whether or not Vitamin K is appropriate. If you do not have enough vitamin K it can increase the risk of fetal problems such as intracranial hemorrhage and hydrocephalus.
  
Prenat Diagn. 2007 Dec 4. Vitamin K deficiency in hyperemesis gravidarum as a potential cause of fetal intracranial hemorrhage and hydrocephalus.
  
Obstet Gynecol. 1998 Oct;92(4 Pt 2):673-5