title: Lactation and lactation related variables; contraception and fertility: an overview of data problems and world trends.
mesh_terms: D000293:Adolescent; D000328:Adult; D001942:Breast Feeding; D003267:Contraception / Q000639:trends*; D003627:Data Interpretation, Statistical; D003906:Developing Countries; D005260:Female; D005298:Fertility; D014943:Global Health; D006801:Humans; D007774:Lactation; D011247:Pregnancy; D012746:Sexual Abstinence