RMU

Introduction: acute fetal distress is a metabolic disorder leading to hypoxia and acidosis that can result in serious lesions and even death. It is one of the main causes for neonatal morbimortality.

Objective: to determine the relationship between the different fetal heart rate patterns corresponding to the suspicion of fetal hypoxia and neonatal results.

Method: a prospective study (November 2001- August 2004) was conducted at the Maternity Service of the Pereira Rossell Hospital. Population: 183 patients were selected according to the following inclusion criteria: single pregnancy, cephalic presentation, labor and electronic monitoring of the fetal heart rate indicating fetal hypoxia.

Pregnancy was interrupted in all emergency cases once diagnosis had been made.

Results: average time for diagnosis at birth was 16.97 minutes, with a standard deviation of 7.7 minutes.

Diagnostic patterns were: intra-partum deceleration 2 (106 cases, 58%), persistent bradychardia (79 cases, 43%), decrease in variability (12 cases, 6%), not promising (complex varied deceleration curves, 12 cases, 6%).

Taking the acid-base state as a neonatal variable, the patterns that best predict the perinatal condition for pH levels below 7.10 is fetal bradychardia, representing positive predictive value of 31.6 ( predictive value of the positive test).

Taking into account the need to refer the newborn to the neonatal care unit, the pattern that best predicts this fact is a decrease in variability of 41.7( positive predictive value).

Conclusion: the methods used in the study to diagnose intra-partum hypoxia have low positive predictive values.