Narrowing of sex differences in infant mortality in Massachusetts.
D002423:Cause of Death; D005260:Female; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality / Q000639:trends*; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000188:drug therapy / Q000401:mortality*; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D012044:Regression Analysis; D012127:Respiratory Distress Syndrome, Newborn / Q000401:mortality; D012744:Sex Ratio