Evaluation of the contraction stress test before 33 weeks' gestation

Area of Science:

• Obstetrics
• Maternal-Fetal Medicine
• Perinatology

Background:

• The reliability of the contraction stress test (CST) in early gestation remains debated.
• Established protocols for CST are primarily documented for late pregnancy.

Purpose of the Study:

• To evaluate the predictive accuracy and clinical utility of the CST before 33 weeks' gestation.
• To assess the association between positive CST results and adverse perinatal outcomes.

Main Methods:

• A prospective study involving 102 patients tested before 33 weeks' gestation.
• Analysis of CST results correlated with urinary estriol levels, Apgar scores, fetal growth, and perinatal mortality.
• Calculation of false positive rates for the CST in this cohort.

Main Results:

• A positive CST was significantly linked to abnormal estriol excretion (60%), low Apgar scores (44%), growth retardation (39%), and increased perinatal mortality (277/1000).
• The CST demonstrated a 22% false positive rate, with no unnecessary premature interventions causing neonatal loss.
• Delivery was safely postponed by an average of 6.1 weeks in patients with negative CST results.

Conclusions:

• The contraction stress test is a valuable predictor of fetal compromise even before 33 weeks' gestation.
• Findings support the early third-trimester application of the CST for improved perinatal care and risk assessment.