Sonographic and Clinical Methods in the Diagnosis of Macrosomia

Abstract

Receiver operator characteristic curves for both clinical and sonographic predictions of macrosomia subsume areas between 0.81 and 0.95, significantly larger than the area of 0.5 that indicates a useless test. Thus, these tests are defined as useful from a statistical point of view. Prediction of macrosomia by clinical or imaging techniques, however, is limited by the substantial false-positive and false-negative rates inherent in these tests. We recommend that physicians continue to use clinical methods to estimate fetal weight, including asking women with parity to provide their own estimates. We recognize that the relative error associated with clinical or sonographic estimates of fetal weight limits their use in clinical practice. Sonographic laboratories may improve their results by performing ROC curve analysis on their own data and by selecting cutoff values that best predict macrosomia in their setting. Serial sonographic measurements that are above the limits chosen to define macrosomia increase the likelihood that a birth weight will be macrosomic. Separate ROC curves must be generated for twins and breech presentations and for patients with diabetes to answer weight-related clinical questions such as mode and timing of delivery. Three-dimensional ultrasound and magnetic resonance imaging are expected to generate ROC curves for estimates of fetal weight that are better than those for two-dimensional ultrasound or clinical estimates. Such analyses have yet to be published.

Accuracy of sonographically estimated fetal weight in 840 women with different pregnancy complications prior to induction of labor

“…Sonographic fetal weight estimation at the 90 th percentile or above has a sensitivity of 7-89% and a specificity of 62-98%. The same calculation for prediction of a birth weight of ≥ 4000 g yielded a sensitivity of 11-100% and a specificity of 48-100% 15 .…”

“…The sensitivity of sonographic EFW in predicting birth weight at the 90 th percentile or more in diabetic pregnancies ranges from 70% to 96%, and the specificity from 77% to 100% 15 . Values for predicting birth weight of ≥ 4000 g are 33-69% and 77-98%, respectively.…”

Resultado perinatal na macrossomia fetal

“…Assim como comparando-se recém-nascidos com peso inferior ou superior a 4500 gramas (OR = 1,09; IC = 0,38-3,10). 5,23,26 . A idade materna avançada relacionouse a gestantes com fetos macrossômicos.…”

“…Fatores genéticos, somados ao estado materno-fetal, também infl uenciam no desenvolvimento 8,17 . Achados epidemiológicos, clínicos e experimentais indicam que o diabetes mellitus gestacional ou pré gestacional, assim como a obesidade ou excesso de ganho de peso durante a gravidez, são fatores de risco signifi cantes para a supernutrição fetal e a macrossomia 5,8,17,23 . Outros fatores de risco para macrossomia fetal são multiparidade, idade materna avançada, antecedente de feto macrossômico, feto masculino e pós-datismo 5,23,26 .…”

“…As complicações maternas são: trabalho de parto prolongado, atonia uterina, parto operatório, lacerações do trato genital, ruptura uterina e as complicações fetais são: distocia de bisacromial levando a trauma de parto (lesão de plexo braquial, fratura de clavícula) e/ou asfi xia 3,4,16,22 . As defi nições mais comumente utilizadas referem-se a peso de nascimento acima de 4000 gramas, 4500 gramas ou 4536 gramas (10 libras) 18,21,23 . O Colégio Americano de Obstetrícia e Ginecologia considera macrossomia acima de 4500 gramas devido ao aumento signifi cativo da morbidade a partir deste peso, porém reconhece o aumento de risco quando o peso é acima de 4000 gramas 2 .…”