Prevalence and aetiology of congenital birth defects, infant mortality and mental retardation in Lahore, Pakistan: A prospective cohort study

Aim: To study the health and development of children in a developing and low-income country. Methods: The health and development of children in Lahore in northern Pakistan have been studied since 1981 in a collaborative project between Pakistani and Swedish university institutions and the Swedish Agency for Research Cooperation with Developing Countries (SAREC). The study described in this paper comprised four different areas in Lahore with different degrees of urbanization and different social conditions. All pregnancies in the four areas were registered during the period March 1984 to July 1986 and were followed up from the 5th month of pregnancy. All 1476 children born after 1 September 1984 were followed up from birth to 12 y of age. Results: The perinatal mortality in the whole material was 5.4%. It was highest in the periurban slum (7.5%) and lowest in the upper-middle class cohort (3.3%). Overall infant mortality was 10%. It was highest (14%) in the periurban slum and lowest (2%) in the upper- middle class group. Overall incidence of serious birth defects was 5%. It was highest in the periurban slum community (7%) and lowest in the upper- middle class cohort (3%). The overall cumulative incidence of severe mental retardation per 100 live births was 1.1. It was highest (2.2) in the periurban slum and lowest ( 0.4) in the upper- middle class group. The overall prevalence of mild mental retardation among 6-10-y-old children was 6.2 per 100. It was highest in the periurban slum (10.5) and lowest (1.3 per 100) in the upper- middle class group. Poverty, malnutrition, birth trauma and consanguinity were common causes of infant mortality and mental retardation in Lahore, Pakistan. Conclusion: Preventive measures with provision of obstetric and health services, services for genetic information and risk evaluation, vaccination programmes and identification of children with retarded development for specific stimulation and habilitation measures, e. g. organized play activities, are important in developing and low-income countries.