M17 Whether child was born by caesarian section
M18 Size of child as reported subjectively by the respondent
M19 Weight of child at birth given in kilograms with three implied decimal places (or grams with
no decimal places). Children who were not weighed are coded 9996. In some countries, the
birth weight was collected in grams, i.e. a total of four digits, whereas other countries
collected the weight in kilograms to one decimal place, i.e. a total of two digits. In the latter
case, the third and fourth digits are set to zeros. In a few countries, the weight was collected
in pounds and/or ounces. For these countries, the original weight variables are stored as a
country-specific variable and this variable contains the weight converted to kilograms.

B0 Twin code gives an order number for each child of a multiple birth. Code 0 indicates a
single birth, code 1-upwards give the number of the child. Twins are ordered in the birth
history with the higher twin codes appearing before the lower twin codes. See the example
of the birth history structure below.

Example Birth History: