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Uruguayan Medical Journal

ISSN: 1688-0390

Vol.15 - Nº 2 - Ago. 1999

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Computarized analysis of the variability of fetal cardiac frequency as a predictor of perinatal acidosis during labor

Rev Med Urug 1999; 15: 110-125
Full text (spanish) |  Full text (spanish) (New windows, pdf) | Abstract


Electronic monitoring of fetal cardiac frequency is the

widest control method of fetal health intralabor. It is an

excellent predictor in negative tests; however, its predictive

value is low in positive tests. This leads to an unnecessary

increase in invasive obstetrical methods, and therefore an

increase in maternal morbimortality, in addition to

increment health care costs. With the aim to improve

electronic monitoring of fetal cardiac frequency as an

efficient predictor in positive tests, we conducted a

prospective case-control study analyzing one parameter

for the monitoring: the variability of fetal cardiac

frequency.The variability was assessed by direct measures:

short-term variability and long-term variability.

A sample of 323 patients in labor were selected in the

maternal care center in Hospital Pereira Rossell during

one year. Eighteen newborns of these patients developed

acidosis at parturition. A control population of 30 normal

patients were matched to the acidosis group. Through a

especially designed software various parameters of the

variability of fetal cardiac frequency were calculated.

We found that in the newborns carriers of acidosis

group the variability is lower; the most significant values

appeared within the previous 30 minutes before the end

of the recording, before birth. During this period, predictive

value of the positive test was 56% for short-term

variability and 50% for long-term variability, p£ 0.04 and

0.05 respectively.

Computarized analysis ofthe variability of fetal cardiac

frequency within the 30 minutes prior birth is an efficient

method to predict acidosis in newborns.