- 
	duration 
- 
	Duration of breast feeding, weeks 
- 
	delta 
- 
	Indicator of completed breast feeding (1=yes, 0=no) 
- 
	race 
- 
	Race of mother (1=white, 2=black, 3=other) 
- 
	poverty 
- 
	Mother in poverty (1=yes, 0=no) 
- 
	smoke 
- 
	Mother smoked at birth of child (1=yes, 0=no) 
- 
	alcohol 
- 
	Mother used alcohol at birth of child (1=yes, 0=no) 
- 
	agemth 
- 
	Age of mother at birth of child 
- 
	ybirth 
- 
	Year of birth 
- 
	yschool 
- 
	Education level of mother (years of school) 
- 
	pc3mth 
- 
	Prenatal care after 3rd month (1=yes, 0=no)