Between 50 and 80 percent of pregnant women reported feeling nausea or vomiting during their first trimester, according to the findings in the Journal of the American Medical Association (JAMA) Internal Medicine.
This condition is often called "morning sickness," although it can affect pregnant women in all day until evening.
In a study of 797 women, the nausea and vomiting associated with a 50-75 percent reduction in the risk of miscarriage, said the study led by Enrique Schisterman of S National Institute of Child Health and Human Development.
All women involved in the study have had one or two miscarriages before. They track back nausea which was written in the diary.
Some experts believe, the nausea can encourage a healthy pregnancy by keeping women eat less, thus reducing the risk of exposure to toxins in food to the fetus.
A decrease in food intake due to nausea also appears to lower the circulating insulin levels and encourage the growth of the placenta, the study showed.
Siripanth Nippita of Beth Israel Deaconess Medical Center and Laura Dodge of Harvard Medical School said, "We hope that the research could further deepen our understanding of the causes of nausea and vomiting in pregnancy," they wrote.