The science behind B-natal.
In 2004, the leading academy of obstetricians and gynecologists issued guidance for physicians on the treatment of morning sickness. After reviewing the scientific literature, they concluded that the first defense against morning sickness is B6 in the form of pyridoxine. 
The role B6 plays in alleviating the nausea and vomiting of morning sickness is poorly understood because the root cause of the condition is poorly understood. The two leading theories for the onset of morning sickness are: 1) hormonal changes and 2) lower blood sugar levels during pregnancy.  It is likely, however, that morning sickness results from a combination of factors.
Whatever the underlying cause, B6 as pyridoxine appears to be the most effective treatment available to reduce morning sickness symptoms. B6 is the most commonly studied treatment methodology and has been recommended by physicians since 1942. 
Additionally, supplementation of Vitamin B6 for expectant mothers may be necessary because many women suffer from B6 deficiency during pregnancy. A lack of Vitamin B6 has been linked to interference with protein absorption, the underutilization of amino acids and the presence of toxemia.
Vitamin B6 is found in a wide variety of foods, including fortified cereals, beans, meat, poultry, fish, and some fruits and vegetables. [4, 5]
Other treatments, such as the use of ginger or antihistamine H1 receptor blockers, are, according to the academy, "based on limited or inconsistent evidence." 
Vitamin B6 is essential for good overall health, whether one is pregnant or not. It is a water-soluble vitamin that exists in three chemical forms: pyridoxine, pyridoxal and pyridoxamine. [4, 6] All three forms have been studied extensively and have been shown to be essential for:
- the synthesis of pyridoxal 5-phosphate, a cofactor of many essential enzymes [4, 7]
- protein metabolism
- red blood cell metabolism
- nervous system function [8, 9]
- immune function [8,9]
- the conversion of tryptophan (an amino acid) to niacin
- the maintenance of normal blood glucose levels [4, 10-12]
A small sampling of the many studies on B6 and morning sickness are summarized below:
- A randomized, double-blind study of 342 women at more than 17 weeks' gestation showed that there was a significant decrease in the mean of post-therapy nausea scores in the pyridoxine group compared with that in the placebo group. 
- A randomized, double-blind study of 59 women experiencing the nausea and vomiting of morning sickness showed that the mean "difference in nausea" score (severe = 7 or above; mild = 7 or below) was significantly reduced following Vitamin B therapy. In fact, after 3 days of therapy, only eight of 31 patients in the Vitamin B cohort had any vomiting, compared with 15 of 28 in the placebo group. 
- A meta-analysis of morning sickness treatment studies found that B6 as pyridoxine was more effective in reducing the severity of nausea. Other treatments included antihistamines, the prescription medication for morning sickness, Debendox, P6 acupressure and ginger. 
- Robertson, A. (2006) Medical Encyclopedia: Morning Sickness. Medline Plus. Available Online [http://www.nlm.nih.gov/medlineplus/ency/article/003119.htm] 9/28/2006.
- Willis, R.S., et al. (1942) Clinical Observations in Treatment of Nausea and Vomiting in Pregnancy with Vitamin B1 and B6. A Preliminary Report. Am J Obstet Gynecol, 44, 265-71.
- Leklem, J.E. (1999) Vitamin B6. In Shils, M., Olson, J.W., Shike, M. and Ross, A.C. (eds.), Modern Nutrition in Health and Disease. Williams and Wilkins, Baltimore, pp. 413-21.
- (2003) USDA Nutrient Database for Standard Reference, Release 16. U.S. Department of Agriculture, Agricultural Research Service. Available Online [http://www.ars.usda.gov/main/site_main.htm?modecode=12354500] 8/24/2006.
- Bender, D.A. (1989) Vitamin B6 Requirements and Recommendations. Eur J Clin Nutr, 43, 289-309.
- Shibata, K., et al. (1995) Effects of Vitamin B6 Deficiency on the Conversion Ratio of Tryptophan to Niacin. Biosci Biotechnol Biochem, 59, 2060-3.
- Gerster, H. (1996) The Importance of Vitamin B6 for Development of the Infant. Human Medical and Animal Experiment Studies. Z Ernahrungswiss, 35, 309-17.
- Trakatellis, A., et al. (1997) Pyridoxine Deficiency: New Approaches in Immunosuppression and Chemotherapy. Postgrad Med J, 73, 617-22.
- Leyland, D.M. and Beynon, R.J. (1991) The Expression of Glycogen Phosphorylase in Normal and Dystrophic Muscle. Biochem J, 278 ( Pt 1), 113-7.
- Oka, T., et al. (1994) Effect of Vitamin B6 Deficiency on the Expression of Glycogen Phosphorylase Mrna in Rat Liver and Skeletal Muscle. Experientia, 50, 127-9.
- Okada, M., et al. (1991) Effect of Vitamin B6 Deficiency on Glycogen Metabolism in the Skeletal Muscle, Heart, and Liver of Rats. J Nutr Sci Vitaminol (Tokyo), 37, 349-57.
- Vutyavanich, T., et al. (1995) Pyridoxine for Nausea and Vomiting of Pregnancy: A Randomized, Double-Blind, Placebo-Controlled Trial. Am J Obstet Gynecol, 173, 881-4.
- Sahakian, V., et al. (1991) Vitamin B6 Is Effective Therapy for Nausea and Vomiting of Pregnancy: A Randomized, Double-Blind Placebo-Controlled Study. Obstet Gynecol, 78, 33-6.
- Jewell, D. and Young, G. (2002) Interventions for Nausea and Vomiting in Early Pregnancy. In The Cochrane Library, Oxford, vol. 1.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.