A multicomponent intervention to reduce home-exposure to second-hand smoke (SHS) during pregnancy and postnatal period: a randomised controlled trial South Asia has one of the highest numbers of male smokers anywhere in the world. As a result, over a third of pregnant women in South Asia are exposed to second-hand smoke in their homes. This has serious health consequences for both mothers (such as increased heart- and lung-related illnesses) as well as the newborn (higher chances of stillbirth, being born prematurely and lung-related illnesses). On the other hand, the antenatal period provides a window of opportunity to change health-related behaviours in the entire family. Interventions that are effective in reducing the exposure of pregnant women to second-hand smoke have been tried successfully in richer countries but have not been adapted for large-scale implementation in lower and middle-income countries.   Our proposed project addresses this gap in two such countries - urban Bangalore, India and peri-urban Comilla, Bangladesh. The sites are situated in a region with the greatest burden of disease from the effects of second-hand smoke globally. The project has two broad aims: The first is to adapt existing knowledge about what is known to work, into an acceptable and feasible intervention that can be delivered to the woman and her family members. This may include informing the woman and her family about the levels of second-hand smoke in her body measured by a simple test on her saliva; educating the whole family about the harmful effects of second-hand smoke on the mother and baby; and using 'communication-techniques' from the field of psychology and behavioural sciences to encourage husband and other family members to change the habit of smoking in the pregnant mother's presence. The second aim is to apply scientific methods to test the effectiveness of this intervention in reducing the exposure of pregnant women and newborn to second-hand smoke in both sites, and to determine the costs versus benefits of implementing such an intervention.   The project will be undertaken in two phases. In Phase 1 (Development Phase: Months 0-12), we will interview pregnant women, their husbands, and other family members to gain an in-depth understanding of all the issues surrounding the problem of second-hand smoke in the household, including barriers we may face in trying to change this. We will use this information to develop an intervention that can overcome these barriers in an acceptable way. During this phase, we will also help our Indian and Bangladeshi counterparts gain the expertise needed to develop such interventions, and in scientific methods to test them. In Phase 2 (Trial Phase - Months 13-36), we will conduct a strict scientific experiment (called a randomized controlled trial) to compare our new intervention with education about second-hand smoke through a leaflet. We will identify 920 mothers in early pregnancy, who are exposed to second hand smoke at home (460 at each site), to receive either the intervention or only the educational leaflet. This will be done in a way that each woman has an equal chance of being in either group. We will collect information on all these mothers and families when we recruit them into our study and then in late-pregnancy, 3 months after both groups have received either of the two interventions. We will also collect information when the new baby is born, and then 3 months after his/her birth. The information collected will include how the pregnancy and birth fared; levels of second-hand smoke in the mothers' and infants' body through a test on their saliva; health of both mother and baby, and smoking behaviours of family members. We will compare the information collected in the two groups to see how well the intervention did. We will also collect more detailed information from some families to understand how the intervention worked (or failed to work, in some cases).   The findings from the study will be shared with key academic, policy and community stakeholders throughout the duration of the project. The Newton Fund builds research and innovation partnerships with developing countries across the world to promote the economic development and social welfare of the partner countries.