Taking a figure of infant mortality rate of 40/100 in LBW infants and assuming that at least 50% of these deaths occurred between 4 weeks and 6 months of age. We expect 20 deaths per 100 infants during the observation period for this study. Assuming a reduction in the mortality rate by 35% with 95% confidence and 80% power, we need a total sample size of 970 infants, which includes 10% excess to account for deviated course (e.g. Loss to follow-up, withdrawal of consent). Assuming a mortality rate reduction of 30% with similar assumption the total (plus 10% for deviated courses) sample size should be 1360 in LBW infants. If we expect a reduction in mortality rate by 25%, the total sample size would be 1900 infants which include 10% for deviated course.