Normal and indeterminate pattern of fetal cardiotocography in admission test and pregnancy outcome

The aim of this study was to evaluate the prognostic value of normal and indeterminate patterns of cardiotocography in admission test (AT) and pregnancy outcome.

A prospective study enrolled 818 intrapartum singleton pregnancies with gestational age of >34 weeks, in the latent phase and with intact membrane. Cases were divided into the high- and low-risk groups. Non-Stress Test was interpreted according to the 2008 National Institute of Child Health and Human Development workshop. Adverse pregnancy outcomes were compared between groups based on AT interpretation.

Out of 818 patients, 492 (60%) were categorized as low-risk and 326 (40%) as high-risk pregnancies. In low-risk patients, 410 (83.3%) had normal and 82 (16.7%) had indeterminate AT. These figures were 249 (76.4%) and 77 (23.6%) in high-risk patients, respectively, and two cases (0.6%) had abnormal AT. In both groups, thick meconium staining, non-reassuring fetal heart rate pattern, cesarean section and cesarean section due to non-reassuring fetal heart rate pattern were significantly more frequent in indeterminate AT than normal ones (P < 0.001). In high-risk pregnancies with indeterminate AT, the risk of low birthweight and neonatal intensive care unit (NICU) admission increased. The positive predictive value was less than 30% in predicting thick meconium staining, non-reassuring fetal heart rate pattern, PH ≤ 7.2 and NICU admission in both groups. Overall, negative predictive value of AT for neonatal death and NICU admission was 100% and 96%, respectively.

Indeterminate patterns of cardiotocography can predict adverse pregnancy outcomes and when facing this condition, obstetricians should act cautiously.