PREDICTING POOR NEONATAL OUTCOME - A COMPARATIVE-STUDY OF NONINVASIVEANTENATAL TESTING METHODS

OBJECTIVE. The assessment of fetal well-being in the third trimester o f pregnancy depends on many variables including fetal size, amniotic f luid volume, umbilical cord arterial Doppler waveforms, the nonstress test, and the biophysical profile, yet little has been written that di rectly compares these variables. In this study, we compared amniotic f luid indexes, umbilical cord arterial Doppler waveforms, nonstress tes ts, and biophysical profiles for pre dieting poor neonatal outcomes in fetuses who are small for gestational age (SGA). SUBJECTS AND METHODS , From April 11, 1994, through August 1, 1995, a cohort of 108 SGA fet uses was identified. Follow-up was available in 97 of these cases. Rec eiver operating characteristic curves were constructed for Doppler sys tolic:diastolic ratios and for amniotic fluid indexes. Student's t tes t and logistic regression analysis were used to compare umbilical cord arterial Doppler imaging, amniotic fluid indexes, the nonstress test, and the biophysical profile for predicting poor neonatal outcome. RES ULTS. Of the 30 fetuses who had poor outcomes, five were emergency ces arean deliveries, three died, three had intracranial hemorrhages, one had a cerebral infarct, 12 had prolonged admission to the neonatal int ensive care unit (NICU) (>10 days), and six had NICU admissions at ter m. Of the variables we assessed, the sensitivities for predicting poor outcome were as follows: cord Doppler imaging, 64%; low amniotic flui d volume (oligohydramnios), 32%; biophysical profile, 18%; and nonstre ss test, 14%. Receiver operating characteristic curves showed that a s ystolic:diastolic ratio of 4.0 and an amniotic fluid index of 5 cm (in dependent of gestational age) were the most accurate cutoff values for predicting poor outcome. Logistic regression analysis showed that amn iotic fluid indexes and umbilical cord arterial Doppler imaging were i ndependent predictors of poor outcome and that the predictive value of the biophysical profile varied according to the amniotic fluid index. CONCLUSION. Doppler waveform abnormalities were the most accurate pre dictor of poor neonatal outcome in a cohort of SCA fetuses. Umbilical cord arterial Doppler waveform analysis should be included in the surv eillance of SGA fetuses.