Morning sickness among pregnant women can pose dangers to the unborn child, especially when it results in severe nausea and vomiting that depletes the amount of folic acid in the woman's body.

A study published in the American Journal of Obstetrics and Gynecology discusses ways of relieving morning sickness using over-the-counter remedies.

Dr. Jennifer Niebyl of the University of Iowa worked on the study with Dr. T. Murphy Goodwin of the Keck School of Medicine at the Univertsity of Southern California.

"Nausea and vomiting during pregnancy significantly impact women's lives in terms of missing work and affecting their personal relationships and responsibilities at home," Niebyl said.

She also said severe vomiting among pregnant women may make then unable to retain enough folic acid, which has been shown to prevent birth defects.

About 35 per cent of pregnant women experience morning sickness that significantly affects their daily lives. One per cent of pregnant women need to be hospitalized for severe vomiting.

The study suggests that before resorting to supplements or drugs, pregnant women should be examined for other causes of nausea and vomiting, such as gallbladder disease, hepatitis, or the presence of twins or other multiples.

Sometimes eating small snacks regularly helps by not allowing the stomach to become empty. "Women can keep crackers by the bedside to eat something right away in the morning, save part of lunch for the middle of the afternoon, and have a protein snack at night," Niebyl said.

She also suggests vitamin B6 can be helpful.

"We don't know how vitamin B6 works," Niebyl said, "but for nearly half the women who take it, vomiting stops and nausea is reduced from severe to mild or moderate."