MONDAY, June 30 (HealthDayNews) -- A treatment commonly used to combat motion sickness in cars, trains and boats may also relieve morning sickness.

That's the finding of a new five-center study appearing in the July issue of Obstetrics and Gynecology. Doctors report on the effectiveness of a wristband that uses an electronic sensor to gently stimulate nerve endings through the skin -- the same method used to control motion sickness.

"It works on the same nerve pathways used in acupuncture to control nausea and vomiting -- the P6 -- but instead of stimulating the nerve ending with a needle, this device uses harmless, painless, mild electrical stimulation to accomplish a similar result," says study co-author Dr. Andrei Rebarber, director of maternal fetal medicine at New York University Medical Center.

When P6 is stimulated, say experts, it sends a signal to the brain to quiet the stomach, which in turn stops the nausea.

For women who can't or choose not to use anti-nausea drugs early in pregnancy, Rebarber says the band is a noninvasive and safe alternative.

Obstetrician Dr. Shari Brasner welcomes the treatment into the pregnancy medicine chest.

"It's important to have as many treatment options as possible -- and when you find something that works and is safe, as this study showed us -- then it's a win-win situation for both mother and baby," says Brasner, an assistant clinical professor at Mount Sinai Medical Center in New York City.

However, she cautions that if a woman tries this treatment and it doesn't work, she shouldn't give up on the idea of feeling better or be afraid to try another option.

"I'm sure this is going to work for a great for many women, but it might not be good for all women. So if you are experiencing morning sickness, be aware that there are other treatment options available that are also safe and effective," Brasner says.

While no one is certain why morning sickness occurs, many doctors believe it is hormone-related. As levels of both estrogen and progesterone soar -- as they do during the first 12 weeks of pregnancy -- Rebarber says it can take the body a little time to get used to the change.

In the process, however, he says raging hormones can kick off a variety of physiological reactions, including nausea and vomiting.

"Often it can be the very first sign of pregnancy," Rebarber says.

While morning sickness is generally not considered dangerous to either mother or baby, it can make a woman extremely uncomfortable. In severe cases, it may prevent her from eating, sometimes to the point where she does not gain the proper amount of weight during her pregnancy.

For a small percentage of women, morning sickness can become so severe that it progresses to the second trimester, and sometimes can last through the entire pregnancy.

"When this occurs, concerns arise about whether the baby is getting the nutrients needed to develop and grow. Some women can't even hold down a prenatal vitamin," Rebarber says.

However, he adds that wearing the wristband early in pregnancy, as soon as morning sickness begins, may help control problems at the earliest stage. And that, he says, may help keep morning sickness from becoming severe.

The three-week clinical trial took place at five hospitals around the nation. Two hundred and thirty women, all between six and 12 weeks pregnant, participated. They reported mild to moderate nausea and vomiting, often with difficulty eating. The intensity and frequency of their symptoms were recorded on the Rhodes Index, a scientific system of documenting these kinds of symptoms.

Each woman was then randomly assigned to wear either a wristband equipped with a battery-operated nerve stimulation device or a sham unit that looked identical.

During the following three weeks, the women were asked to wear the wristband continually and to keep a record of their morning sickness symptoms. In the end, 187 women finished the trial, with equal dropout rates from both groups. Only one woman withdrew due to a problem with the wristband itself, which involved an irritation where the band touched her skin.

The women who used the wristband had far less nausea and vomiting, and their morning sickness appeared to stop sooner than those using the fake wristband. In addition, the women wearing the nerve stimulation band gained nearly three times the weight as the women wearing the sham band -- 2.9 pounds as compared to 1.2 pounds. In addition, none of the women or their babies suffered any complications as a result of the treatment.

"We were pleased to see that the wristband worked and that it was safe, and it is definitely an option a pregnant woman should consider as soon as morning sickness begins," Rebarber says.