title: Biosocial trends at first pregnancy in Mexican women not exposed to contraceptive methods.
authors.forename: V S
authors.initials: VS
authors.lastname: Vital-reyes
authors.forename: M J
authors.initials: MJ
authors.lastname: Hernandez Beltran
authors.forename: F G
authors.initials: FG
authors.lastname: Roig
authors.forename: V
authors.initials: V
authors.lastname: Cortes-gallegos
mesh_terms: D000367:Age Factors; D000569:Americas; D001519:Behavior; D001695:Biology; D003075:Coitus; D003625:Data Collection; D003710:Demography; D003906:Developing Countries; D007246:Infertility; D007407:Interviews as Topic; D007843:Latin America; D008800:Mexico; D009656:North America; D011153:Population; D011154:Population Characteristics; D011247:Pregnancy; D012098:Reproduction; D012106:Research; D012307:Risk Factors; D012725:Sexual Behavior
keywords: Age Factors; Americas; Behavior; Biology; Coital Frequency--women; Data Collection; Demographic Factors; Developing Countries; First Intercourse--women; Infertility; Interviews; Latin America; Mexico; North America; Population; Population Characteristics; Pregnancy; Reproduction; Research Methodology; Research Report; Risk Factors; Sex Behavior