Presentation on theme: "Low Birth Weight MICS3 Data Analysis and Report Writing."— Presentation transcript:
Low Birth Weight MICS3 Data Analysis and Report Writing
Background Low birth weight carries a range of grave health risks for children. Low birthweight babies face a greatly increased risk of dying during their early monthsand years. Those who survive have impaired immune function and increased risk of disease; are likely to remain malnourished, with reduced muscle strength, throughout their lives, and suffer a higher incidence of diabetes and heart disease in later life.
Background Children born underweight also tend to have a lower IQ and cognitive disabilities that affect their performance in school and their job opportunities as adults.
International Goals & Targets Reduction in the rate of low birth weight by at least one-third of the current rate
Definition of Indicator % of infants who weigh less than 2,500 grams (2.5 kg) at birth Numerator: Number of last live births in the 2 years preceding the survey weighing below 2,500 grams (2.5 kg) Denominator: Total number of last live births in the 2 years preceding the survey
Methodological Issues Prior to about 1990, estimates of low birth weight were based primarily on data from health facilities. These data are often biased. Since about 1990, birth weight information has been collected systematically from mothers participating in national HH surveys. Early assessments of survey data showed that mothers are often unable to provide numerical birth weights, mostly because they are not weighed at birth.
Methodological Issues Percentage of births NOT weighed
Methodological Issues Comparison of births weighed and not weighed
Methodological Issues Adjustment Procedure An adjustment procedure was proposed by Boerma and colleagues (1996) that uses additional information on the mothers assessment of the childs size at birth. MICS and DHS surveys collect information on mothers assessment of birth size. Three questions: –When [childs name] was born, was he/she very large, larger than average, average, smaller than average, or very small? –Was [childs name] weighed at birth? –If yes, what did [childs name] weigh?
Methodological Issues Adjustment Procedure Numerical birth weight Mothers assessments of birth size 100% of survey sample
Methodological Issues Heaping of Birth Weight, Tanzania 1999
Methodological Issues Effect of Adjustment
Methodological Issues Note that updated estimates are available in The State of the Worlds Children 2006
Methodological Issues In MICS, 2 items in the questionnaire are used to estimate low birth weight. – Mothers recall of the childs size at birth (i.e. very small, smaller than average, larger than average, very large) – Mothers recall of the childs weight or the weight recorded on a health card if the child was weighed at birth
Tabulation Plan Table NU.8: Low Birth Weight
Methodological Issues Tabulate childrens size by their weight for those weighed at birth to obtain proportion of births in each size category who weighed less than 2,500 grams Multiply this proportion by the total number of children in size category to obtain estimated number of children by size category with low birth weight Sum the estimated number of children in each size category with low birth weight in order to obtain the total number of low birth weight children Divide by the total number of live births to obtain the percentage with low birth weight
Tabulation Plan Table NU.8E: Low Birth Weight Estimation