within the uterus. CP area is related to the number of maternal vessels that can supply the intervillous blood space. BWT shows measurable associations with ...
S156 SMFM Abstracts
December 2003 Am J Obstet Gynecol
344
MEASURES OF RELATIVE UMBILICAL CORD INSERTION ACCOUNT FOR 26% OF BIRTHWEIGHT VARIANCE CAROLYN SALAFIA1, JOHN THORP, JR2, ELIZABETH MAAS1, BARBARA EUCKER2, FRANCES SMITH2, DAVID SAVITZ3, 1EarlyPath Diagnostic Services, Epidemiology and Pathology, Larchmont, NY 2University of North Carolina at Chapel Hill, Obstetrics/ Gynecology, Chapel Hill, NC 3University of North Carolina at Chapel Hill, Chapel Hill, NC OBJECTIVE: Standard placental measures at delivery include the distance in cm from the umbilical cord insertion (UCI) to the closest placental margin. Using digital image analysis, much more detailed information can be collected, and moreover, measurements can be analyzed in relation to other potentially meaningful landmarks. This study explores the associations of standard and novel measures of UCI to birthweight (BWT). STUDY DESIGN: The Pregnancy, Infection and Nutrition (PIN) study is a cohort study of pregnant women recruited at mid-pregnancy from an academic health center in central North Carolina. All PIN subjects plan delivery at the UNC Women’s Hospital. The population was restricted to 287 placentas delivered after 24 completed weeks’ gestation. A digital image of fetal surface is analyzed using Scanalytics software (Fairfax, VA). The placental edge with the shortest distance to the site of membrane rupture is identified and positioned at 6 o’clock. The perimeter of the placenta is traced, and the UCI, marked. A standard measure of the distance from UCI to nearest placental margin is taken, and novel measures of the distance from UCI to the centroid, the weighted center of the placenta area. A stepwise regression entered first the standard, next the novel UCI measure, and last GA, in models predicting BWT. r RESULTS: Standard UCI–nearest placental margin accounted for 8% of BWT variance (r); addition of UCI-centroid captured an additional 18% of BWT r. Addition of GA captured an additional 40% of BWT r, but the UCI measures retained independent effects on BWT. Each cm of increasing distance from the nearest placental margin contributed 115 g (5-95% CI 80-151) increased BWT. Each cm of increasing distance of UCI from the centroid contributed 92 g (5-95% CI 57-128) BWT. CONCLUSION: BWT shows measurable associations with very early pregnancy events; these data may contribute to clarifying timing and mechanisms of BWT associations with long-term health risks.
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MEASURES OF CHORIONIC PLATE AREA ACCOUNT FOR 45% OF GESTATIONAL AGE VARIANCE CAROLYN SALAFIA1, ELIZABETH MAAS1, JOHN THORP, JR2, BARBARA EUCKER2, FRANCES SMITH2, DAVID SAVITZ3, 1ColumEarlyPath Diagnostic Services, Epidemiology and Pathology, Larchmont, NY 2University of North Carolina at Chapel Hill, Obstetrics/Gynecology, Chapel Hill, NC 3University of North Carolina at Chapel Hill, Chapel Hill, NC OBJECTIVE: Standard placental measures at delivery include the largest and smaller diameters of the normally round to ovoid chorionic plate (CP). While many ‘‘errors in outline’’ of the CP are seen, their clinical significance is often obscure. Using digital image analysis, much more detailed information on CP growth can be collected. This study explores the associations of standard and novel measures of the CP to birthweight (BWT). STUDY DESIGN: The Pregnancy, Infection and Nutrition (PIN) study is a cohort study of pregnant women recruited at mid-pregnancy from an academic health center in central North Carolina. All PIN subjects plan delivery at the UNC Women’s Hospital. The population was restricted to 291 placentas delivered after 24 completed weeks’ gestation. A digital image of fetal surface is analyzed using Scanalytics software (Fairfax, VA). The longest diameter and the smaller diameter, measured at the widest point perpendicular to the longest diameter, were captured from digital images. From a tracing of the plate outline, perimeter, area, and measures of plate irregularity were calculated. 55 cases were re-measured by the same morphometrist for reliability assessment. A stepwise regression entered first the standard and next the novel CP measures in models predicting GA. RESULTS: ICC (3,1) for the novel CP measures ranged from 0.96-0.99. The smaller CP diameter accounted for 25% of GA variance (r); addition of novel CP measures captured an additional 20% of GA r. Of the 25% of GA attributed to standard CP measures, all but 2% r was captured by novel CP measures. CONCLUSION: CP growth reflects the early expansion of the placenta within the uterus and is related to the number of maternal vessels that can supply the intervillous blood space. This early expansion may influence timing of parturition. GA shows measurable associations with CP growth that are captured in highly reproducible digital image analysis of CP.
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CHORIONIC PLATE MEASURES ACCOUNT FOR 39% OF BIRTHWEIGHT VARIANCE CAROLYN SALAFIA1, ELIZABETH MAAS1, JOHN THORP, JR2, BARBARA EUCKER2, FRANCES SMITH2, DAVID SAVITZ3, 1EarlyPath Diagnostic Services, Epidemiology and Pathology, Larchmont, NY 2University of North Carolina at Chapel Hill, Obstetrics/Gynecology, Chapel Hill, NC 3University of North Carolina at Chapel Hill, Chapel Hill, NC OBJECTIVE: Standard placental measures at delivery include the largest and smaller diameters of the normally round to ovoid chorionic plate (CP). While many ‘‘errors in outline’’ of the CP are seen, their clinical significance is often obscure. Using digital image analysis, much more detailed information on CP growth can be collected. This study explores the associations of standard and novel measures of the CP to birthweight (BWT). STUDY DESIGN: The Pregnancy, Infection and Nutrition (PIN) study is a cohort study of pregnant women recruited at mid-pregnancy from an academic health center in central North Carolina. All PIN subjects plan delivery at the UNC Women’s Hospital. The population was restricted to 288 placentas delivered after 24 completed weeks’ gestation. A digital image of fetal surface is analyzed using Scanalytics software (Fairfax, VA). The longest diameter and the smaller diameter, measured at the widest point perpendicular to the longest diameter, were captured from digital images. From a tracing of the plate outline, perimeter, area, and measures of plate irregularity were calculated. A stepwise regression entered first the standard, next the novel CP measures, and last GA, in models predicting BWT. RESULTS: The smaller CP diameter accounted for 21% of BWT variance (r); addition of novel CP measures captured an additional 18% of BWT r. Addition of GA captured an additional 27% of BWT r. Of the 39% of BWT attributed to CP measures, all but 8% of BWT r was mediated by a relationship between CP measures and GA. CONCLUSION: CP growth reflects the early expansion of the placenta within the uterus. CP area is related to the number of maternal vessels that can supply the intervillous blood space. BWT shows measurable associations with CP growth, which are only partly captured by GA.
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ACCURACY OF PATIENT RECALL OF INTRAPARTUM EVENTS LINDA M. HOPKINS1, AARON B. CAUGHEY1, CHRISTINA WASSEL FYR2, ERIC VITTINGHOFF2, DAVID THOM3, 1University of California, Obstetrics and Gynecology, San Francisco, CA 2University of California, Epidemiology and Biostatistics, San Francisco, CA 3University of California, Family and Community Medicine, San Francisco, CA OBJECTIVE: To determine the accuracy of patient recall compared to chart abstraction for distant intrapartum events and to evaluate predictors of increased accuracy. STUDY DESIGN: A random sample from a population-representative cohort of 2100 ethnically diverse women. Intrapartum events reported by subjects were compared to data abstracted from labor and delivery records. Outcomes were assessed for sensitivity, specificity, and positive predictive value (PPV) of patient recall. Logistic regression with repeated measures was used to determine predictors of inaccuracy of patient recall. RESULTS: A total of 286 births among 139 women were analyzed. Sensitivity, specificity, and PPV of recall were low to moderate for each of the selected variables (Table). Women were most likely to accurately recall regional anesthesia and least likely to accurately recall laceration requiring repair. Women who recalled having had an episiotomy had the highest likelihood of being correct. Significant predictors of accurate recall of oxytocin use were increasing numbers of births (P = .01) and Asian race (P = .05). Increasing age was associated with incorrect recall of oxytocin (P = .01) and regional anesthesia (P = .01). Compared to white women, Latina (OR 2.8, P = .02) and African American (OR 4.4, P = .02) women were more likely to incorrectly recall episiotomy, and Asian women were more likely to incorrectly recall regional anesthesia (OR 4.1, P = .03). CONCLUSION: The accuracy of patient recall for distant intrapartum events is limited. Reliance on patient reports alone may lead to recall bias. The degree of bias differs among the variables and can be estimated from the data provided. No patient or delivery characteristics consistently predicted better recall of intrapartum events.
Recall outcomes Variable Oxytocin Regional Anesthesia Laceration Episiotomy
Sensitivity
Specificity
PPV
0.57 0.82 0.59 0.64
0.75 0.80 0.65 0.78
0.60 0.71 0.67 0.89
