Pyridoxine is the chemical name for what's more commonly called vitamin B6, a water-soluble vitamin that your cells use in a number of chemical reactions. Both pregnant and non-pregnant women need vitamin B6 as a regular component of their diet. For some individuals, pyridoxine in larger quantities may help alleviate symptoms of morning sickness.
Morning Sickness
If you're in the early weeks of pregnancy -- typically between pregnancy weeks six and 13 -- you're likely to experience some degree of morning sickness. In their book "What To Expect When You're Expecting," Heidi Murkoff and Sharon Mazel explain that the reason morning sickness is so common is that your hormone levels -- particularly levels of hCG and progesterone -- rise rapidly in the early weeks of pregnancy, which can lead to nausea.
Medications
Unfortunately, as uncomfortable as morning sickness can be, most obstetricians prefer not to prescribe medication for the nausea, since it's best to avoid medication during pregnancy as much as possible. Up until the 1980s, however, there was a pyridoxine-containing pharmaceutical called Bendectin available for purchase in the U.S. that many obstetricians recommended to their patients, explain Drs. Michael Roizen and Mehmet Oz in their book "You: Having A Baby."
Bendectin Effects
Bendectin actually combined two different chemicals -- pyridoxine and an antihistamine called doxylamine, which is sold under the brand name Unisom. There was never any evidence that Bendectin caused harm to pregnant women or their unborn children, note Drs. Roizen and Oz, but the pharmaceutical was removed from the market in the U.S. in the 1980s. It remains available in Canada and many other countries worldwide, and is widely considered one of the safest treatments for pregnancy-related nausea.
Mechanism
The mechanism whereby pyridoxine alleviates symptoms of morning sickness is unclear. It doesn't appear that vitamin B6 deficiency leads to morning sickness, notes Drs. K. Schuster and colleagues in a 1985 study published in "Human Nutrition -- Clinical Nutrition," a scholarly journal. Furthermore, quantities of pyridoxine required to treat morning sickness are nearly 10-fold higher than quantities recommended for routine daily use. Regardless, for whatever reason, pyridoxine does seem to alleviate morning sickness, particularly in combination with doxylamine.
Use of Pyridoxine
Drs. Roizen and Oz note that, with your obstetrician's permission, you can recreate Bendectin to treat your morning sickness by taking 10 mg of pyridoxine and 10 mg of Unisom or generic doxylamine. The doxylamine is a very early-generation antihistamine, and is likely to make you feel very sleepy, at least until you get used to having it in your system. Still, for women with severe morning sickness, this may be much less irritating than the nausea. Pyridoxine in these doses doesn't appear to have negative side effects.
References
- "What to Expect When You're Expecting"; Heidi Murkoff and Sharon Mazel; 2008
- "You: Having A Baby"; Michael Roizen, M.D. and Mehmet Oz, M.D.; 2009
- "Human Nutrition -- Clinical Nutrition"; Morning sickness and vitamin B6 status of pregnant women; K. Schuster et al; January 1985
