Participants and sampling
Incorporation models for the examination were expectant ladies with clinical cards, prenatal registration arrangements, and who ready to partake in the investigation. The expectant ladies who declined to finish the surveys because of mental, actual ailment, or different reasons (for example neglecting to have sufficient opportunity) were expunged.
An aggregate of 1,056 expectant ladies, having set up a clinical card for a prenatal registration during pregnancy from March to April in 2020 in Guizhou Province, China, was selected for the examination.