Here is a link to one of the articles, you will see the others on the right side bar of the page.
Although Bangladesh continues to rank as one of the poorest countries in South Asia, over the past 4 decades, the country has been able to make huge strides to improve infant and child health. Indeed the progress that Bangladesh has made in improving life expectancy, as well as, infant, child, and maternal mortality is remarkable given the country's poverty.
The Lancet articles describe some of the reasons for these impressive improvements. Specifically Bangladesh has specifically focussed its health programs on women and the poor. This had led to larger improvements in health indicators in the poorest quintile of the population compared to the upper quintiles. This graph shows the impressive improvements in child (under age 5) mortality over the past 40 years.
Bangladesh has worked very closely with the local NGO to community to focus on achieving its health goals. Specifically the NGO sector has been very involved in the Expanded Programme on Immunization. On National Immunization Day in 2012, over 600 000 workers were able to distribute polio vaccines and Vitamin A capsules to 24 million children! The vaccination rates for children in Bangladesh are better than those of all other countries in South Asia.
Fertility has also declined dramatically from 6.3 births per woman in the early 1970's to 2.5 in 2010. Fertility rates vary across the country with higher rates persisting in the eastern areas due to these areas being more remote and having less access to local health services.
With each of these areas for gain (mortality, immunization, and fertility), local community health workers have been instrumental in achieving the progress.
For example: (To quote from one of the articles)
"The present family planning programme in Bangladesh began in 1977 as an experimental pilot project in the Matlab subdistrict, with young, educated women to provide family planning services directly to the homes of couples. The effect on fertility reduction was noted almost immediately. After testing and modification to assess feasibility and success, the programme was gradually scaled up across the country through existing government systems. ... This approach led to deployment of thousands of full- time female fieldworkers (family welfare assistants) under the family planning wing of the Ministry of Health and Family Welfare. Each family welfare assistant undertook community-based distribution of family planning methods through household visits every two months in her catchment area of about 4000 people. With the supervisory mechanisms in place, coverage and intensive follow-up underscored much of the success of this approach."
Poverty, low female autonomy, and cultural restrictions on the mobility of women have meant that this approach is extremely effective despite ongoing extreme poverty, low levels of female education, and persistent young age of marriage. These factors are generally closely correlated with female fertility in developing countries.