CLINICAL AND SONOGRAPHIC ESTIMATES OF BIRTH-WEIGHT AMONG DIABETIC PARTURIENTS

Objective: To determine the relative accuracy of clinical and sonograp hic estimates of fetal weight (EFW) among parturients with diabetes re quiring insulin (White's classifications A2 and higher). Methods: In e arly labor, clinical EFW was followed by sonographic mensuration of fe tal parts, At the completion of the study, sonographic EFW was calcula ted using abdominal circumference and femur length. Student's t test, Wilcoxan test, and chi square test were used to assess the relative ac curacy of the two methods of assessing birth weight. Results: Among 94 parturients with various classifications of diabetes, the clinical es timate of birth weight has a significantly higher simple error (-180.3 + 419.5 g) but not a significantly higher mean standardized absolute error (130.7 +/- 130.1 g/kg) than sonographic prediction (-139.3 +/- 4 47.1 g, 115.6 +/- 90.8 g/kg, respectively). Analysis of the data, acco rding to gestational age, indicates that clinical EFW is more accurate than sonographic EFW among term (n = 67) parturients with diabetes, b ut both methods are comparable in preterm (n = 27) parturients. Howeve r, when the data are analyzed according to birth weight, EFW by Leopol d maneuvers is significantly more accurate than those obtained sonogra phically in infants weighing 2500-3999 g (n = 66) and >4000 g (n = 12) . Conclusion: In term gestations of diabetic mothers and those infants with a birth weight of 2500 g or more, the clinical estimate of birth weight is more accurate; however, in preterm diabetic pregnancies, cl inical and sonographic estimates are equal.