Nonreactive contraction stress test: clinical significance

Area of Science:

• Obstetrics and Gynecology
• Perinatal Medicine
• Fetal Monitoring

Background:

• The contraction stress test (CST) is a method used to assess fetal well-being.
• Nonreactive results on CSTs can be concerning, but their clinical significance varies based on test category.

Purpose of the Study:

• To evaluate the perinatal outcomes associated with nonreactive contraction stress tests.
• To determine if nonreactive negative or equivocal CSTs are associated with increased perinatal mortality and morbidity.

Main Methods:

• Retrospective analysis of 4629 contraction stress tests performed between 1976 and 1980.
• Categorization of CST results into negative, equivocal, and positive, and assessment of reactivity.
• Comparison of perinatal mortality and Apgar scores between reactive and nonreactive test groups.

Main Results:

• Overall, 1.0% of CSTs were nonreactive.
• Nonreactive positive CSTs (27.0%) were significantly associated with increased perinatal mortality and low Apgar scores.
• Nonreactive negative (0.2%) and equivocal (1.7%) CSTs, excluding anomalous fetuses, did not show increased perinatal deaths or low Apgar scores.

Conclusions:

• The clinical significance of a nonreactive CST is primarily linked to positive results.
• Nonreactive negative or equivocal CSTs, when considered as the worst test result, do not appear to be associated with increased perinatal mortality or morbidity.
• Standardization of CST criteria and interpretation is recommended.