natal complications that require special and expensive medical care . In addition, multiple-birth children are at much greater risk of birth defects and/or disabilities and accounted for larger percentage of prenatal deaths . Therefore, mortality of these high-risk groups contributes to the higher rate of childhood mortality especially during the early period of life. We also found that large majority of multiple birth children died in infancy. This is consistent with finding from previous study. The perinatal period has long been recognized as a period of increased risk for twins. . It is possible that the use of the curative services, which are needed in emergency situations, could be under-utilized by mothers of twins. However, the increased mortality risk extends into the post-neonatal and childhood period, when the mortality of twins is more than twice the value of the mortality of singletons
Consistent with previous studies [30-34], we found that mother's education has strong negative effect on infant mortality, independent of other factors. There is a very large literature from around the world that demonstrates the significance of mother's schooling to lower mortality outcome among children. The pathways from mother's schooling lower mortality rate include, but are not limited to, greater likelihood of obtaining pre- and ante-natal care, seeking prompt medical care at the first sign of a child's illness, and more appropriate breast feeding and nutritional supplementary practices. This and previous studies [14,35-40]have provided evidence that children born in the poorer households are a much greater risk of dying in infancy than children born in better-off households. Poverty affects infant survival through insufficient food intake, greater exposure to infections, and lack of access to vaccinations and basic health care.
Finally, it is necessary to discuss the limitations of this study, as well as its strengths. The present study was performed in a large nationally representative sample with stratified random sampling. The first potential limitation of this study is the cross-sectional nature of the analysis. The study uses censored, synthetic cohort life table based on the birth history of children and reported characteristics of mothers and households. While some of the covariates used in our analysis, such as child's sex, antenatal care, mother's age at childbirth are fixed covariates, others, such as mother's education, household access to clean water and sanitation, and urban/rural residence could have changed during the last 5 years. In the analysis, all covariates are assumed to have been fixed during the study period. However, because the household characteristics and many of the other background characteristics are not likely to have changed much in the past 5 years and because the main finding in the analysis is relationship of multiple birth status and child survival, the cross-sectional effects estimated in these studies are good measures of child survival among multiple births.
Another limitation of this study worth mentioning is that measuring wealth is problematic. Many of the household wealth indices use assets that are more likely to be found in urban areas than in rural areas. Thus, most of the rural households will be in the lowest wealth category even if they have other indicators of wealth (e.g., livestock or farm machinery). The consequence of this misclassification would be to lower the mortality risks of rural households. Another limitation with household wealth indices derived from DHS is that they are based on current status data so that they might not capture the true level of household wealth during the infancy of children born several years before the survey. However, since these analyses are restricted to births within five years of the surveys, this bias will not be substantial.
In summary, we found that children born multiple births are more likely to die during the first year of life compare to children born singletons, independent of child's sex, birth order, pregnancy care and d