Certain population groups are at risk for inadequate prenatal care and transmission of perinatal infections. Philadelphia's birth cohort comprises largely at-risk groups and its infant mortality rate is among the nation's highest. This study identifies factors associated with infectious disease screening, treatment, and prevention in Philadelphia. Delivery charts for a probability sample of 550 patients were reviewed. Demographic factors associated with prenatal and delivery care were identified through Pearson chi-square, analysis of variance, and stepwise logistic regression analysis. Nonstandard and incomplete documentation complicated abstraction. Some prenatal care was noted in 95% of the records and screening varied by disease. Factors independently associated with care include maternal race, insurance status, and maternal age. Screening for infections with well-established recommendations (hepatitis B virus, rubella, syphilis) occurred more often than for group B streptococcus, HIV, hepatitis C virus, and varicella. Adoption of standard reporting forms and processes could improve practice and aid in quality improvement efforts and patient communication.