[A program for obtaining a cohort for perinatal studies. I. Justification and strategy].
D005260:Female; D006285:Health Planning / Q000458:organization & administration; D006297:Health Services Accessibility; D006801:Humans; D008800:Mexico; D010500:Perinatology; D011247:Pregnancy; D012959:Socioeconomic Factors
Programa para la captación de una cohorte de estudios perinatales. I. Justificación y estrategia.