There are several reasons behind it:

First seven days:

    Underweight at birth, difficult delivery, breathing problem, premature delivery.

Within one month:

   Apart from the reasons given above, death can be due to loose-motions, pneumonia, measles or whooping cough.

From 1st month to 12th month:

    Malnutrition, pneumonia, fever, whooping cough, loose-motion

From one year to five years:

   Malnutrition, measles, loose-motions, pneumonia.

Prevention:

For the prevention of the conditions mentioned earlier, the following measures are very important:

1. Precautionary measures for premature and underweight birth.
2. Breast-feeding.
3. Complete course of vaccinations at right times.
4. Monitoring the child's growth.