Table 1 Assignment of independent variables
Characteristic | Assignment |
|---|---|
 Demographic characteristics | |
  Age | < 30 = 0; ≥30 = 1 |
  Education level | Primary school = 0; |
Junior middle school or above = 1 | |
 Occupation (whether there is a job) | No = 0; Yes = 1 |
  State of physical health | Unhealthy = 0; Healthy = 1 |
 Pregnancy characteristics | |
  First child | No = 0; Yes = 1 |
  Regular antenatal examination | No = 0; Yes = 1 |
  Participate in pregnancy training | No = 0; Yes = 1 |
  Taking folic acid | No = 0; Yes = 1 |
 Family factors | |
  Family economic situation | No basic living allowance = 0; |
With basic living allowance = 1 | |
  Once being internal migrant worker | No = 0; Yes = 1 |
  Be internal migrant worker (husband) | No = 0; Yes = 1 |
  Whether to live with elders | No living with elders = 0; |
Live with parents-in-law = 1; | |
Live with parents = 2; | |
Live with parents-in-law and parents =3 | |