Letter: Social disadvantage.
D002662:Child Health Services; D002675:Child, Preschool; D004200:Diseases in Twins; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology; D009748:Nutrition Disorders / Q000453:epidemiology; D010922:Placenta Diseases; D011247:Pregnancy; D012959:Socioeconomic Factors; D006113:United Kingdom