The size of the symbol for each odds ratio (a square for each study and a diamond for the overall analysis) is proportional to the sample size, in order to indicate the relative precision of the estimated risk. Arrows indicate confidence limits that are off the scale. Asterisks indicate odds ratios that are off the scale (0 or infinity) or that are not defined. P values are for tests of homogeneity. CI denotes confidence interval, PI protease inhibitors, PACTG 185 Pediatric AIDS Clinical Trials Group study 185, PACTS Perinatal AIDS Collaborative Transmission Studies, UCLA the University of California at Los Angeles, UMiami the University of Miami, USC the University of Southern California, and WITS the Women and Infants Transmission Study.

The size of the symbol for each odds ratio (a square for a study and a diamond for the overall analysis) is proportional to the sample size, in order to indicate the relative precision of the estimated risk. Arrows indicate confidence limits that are off the scale. Asterisks indicate odds ratios that are off the scale (0 or infinity) or that are not defined. P values are for tests of homogeneity. Data on birth weight were not available for the infants of 38 women. CI denotes confidence interval, PI protease inhibitors, PACTG 185 Pediatric AIDS Clinical Trials Group study 185, PACTS Perinatal AIDS Collaborative Transmission Studies, UCLA the University of California at Los Angeles, UMiami the University of Miami, USC the University of Southern California, and WITS the Women and Infants Transmission Study.