BackgroundPoor oral health, such as periodontal (gum) disease, has been found to be associated with an increased risk of adverse pregnancy outcomes including preterm birth, low birth weight, and neonatal and infant mortality, especially in low-and middle-income countries. However, there is little or no access to preventive dental care in most low-and middle-income countries. We propose to develop and test a “Mouth Rinse Intervention” among pregnant women to prevent the progression of periodontal disease during pregnancy and reduce adverse birth and neonatal outcomes in a rural county of China.Methods/DesignThis is a randomized controlled clinical trial. A sample of 468 (234 in each arm of the study) women in early pregnancy with periodontal disease will be recruited for the study. Periodontal disease will be diagnosed through the methods of Periodontal Screening and Recording. All women diagnosed with periodontal disease will be randomly allocated into the intervention or control group. Women assigned in the intervention group will be provided with non-alcohol antimicrobial mouth rinse containing cetylpyridinium chloride throughout the pregnancy and oral health education. Women in the control group will receive a package of tooth brush and paste, plus oral hygiene education. Women will be followed-up to childbirth until the 42nd day postpartum. The main outcomes include mean birthweight (gram) and mean gestational age (week).DiscussionCompared with conventional mechanical ‘scaling and root planning’ periodontal treatment during pregnancy, our proposed mouth rinse intervention could be a simple, cost-effective, and sustainable solution to improve both mother’s oral health and neonate outcomes. If the mouth rinse is confirmed to be effective, it would demonstrate great potential for the application in other low- or middle-income countries to prevent adverse birth outcomes such as preterm birth and low birth weight and to reduce neonatal and infant mortality.Trial registrationThis trial was registered with Chinese Clinical Trial Registry (ChiCTR): (#ChiCTR-TRC-13003768) on November 06, 2013.