New York: Nausea and vomiting that occurs during pregnancy, often termed as "morning sickness", is associated with a lower risk of miscarriage, a study has found. Morning sickness typically begins in the morning and usually resolves as the day progresses. For most women, nausea and vomiting subsides by the fourth month of pregnancy. Others may have these symptoms for the entire duration till delivery. Though the cause of morning sickness is not known, but the study revealed that it protects the foetus against toxins and disease-causing organisms in foods and beverages. "Our study evaluates symptoms from the earliest weeks of pregnancy, immediately after conception, and confirms that there is a protective association between nausea and vomiting and a lower risk of pregnancy loss," said lead author, Stefanie N. Hinkle, scientist at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) -- a public health research organisation in Maryland, US. For their study, the team analysed a total of 797 women who had tested positive for pregnancy, with 188 ending in miscarriage. By the eighth week of pregnancy, 57.3 per cent of the women reported experiencing nausea and 26.6 per cent reported nausea with vomiting. The researchers found that women experiencing 'morning sickness' were 50 to 75 per cent less likely to have pregnancy loss, compared to those who had not experienced it. The study, appearing in JAMA Internal Medicine, was conducted by researchers at and other institutions.