Among the many challenges of pregnancy, morning sickness is one of the most vexing for expectant mothers. A July 2003 "American Family Physician" review states that up to 80 percent of pregnant women are affected by morning sickness. Hyperemesis gravidarum, a severe form of morning sickness, complicates one in 200 pregnancies. Although most women weather morning sickness relatively easily, hyperemesis gravidarum can negatively impact maternal and fetal health. Vitamin B6 is often useful for dealing with vomiting during pregnancy.
The physiologic mechanism that triggers morning sickness and hyperemesis gravidarum has not been identified. Psychological factors do not appear to play a role. Hormonal influences are the most likely culprits contributing to nausea and vomiting in pregnancy. Changes in circulating estrogen or progesterone levels or rapidly increasing levels of placenta-derived human chorionic gonadotropin -- hCG -- have been implicated in some studies. A 2010 study published in "Nature and Science" suggested that infection with Helicobacter pylori plays a role in many cases of hyperemesis gravidarum.
Morning sickness and hyperemesis gravidarum usually begin during the first trimester of pregnancy, and other causes of vomiting are usually not considered when symptoms are typical of these conditions. However, some causes of vomiting, such as gallbladder disease, acute fatty liver or kidney infections, are actually more common during pregnancy. Other conditions, such as pancreatitis, ulcers, hepatitis, appendicitis or thyroid disease, should be ruled out if your vomiting becomes severe and persistent, particularly if your symptoms grow worse after 9 weeks of gestation. Although useful for morning sickness, vitamin B6 is ineffective for most other causes of vomiting during pregnancy.
Morning sickness can usually be addressed through dietary changes, emotional support and possibly the use of alternative remedies, such as ginger, acupuncture or acupressure. The September 2007 issue of "Australian Family Physician" outlines the use of vitamin B6 at a dosage of 25 mg three times daily for both morning sickness and hyperemesis gravidarum. This recommendation mirrors those of earlier studies, such as a clinical trial published in the July 1991 issue of "Obstetrics and Gynecology."
Considerations and Precaution
Morning sickness is a common pregnancy-related condition. Hyperemesis gravidarum is a severe form of morning sickness. Vitamin B6, at a dosage of 25 mg three times daily, has been shown to ameliorate nausea and vomiting associated with pregnancy. Persistent vomiting caused by hyperemesis gravidarum or any other condition presents a threat to the health of both an expectant mother and her fetus. If you experience severe nausea and vomiting that don't respond to dietary changes, rest, fluids and vitamin B6, consult your physician.