Analysis of Factors Contributing to Antenatal Corticosteroid Administration in Threatened Preterm Labor

Abstract

INTRODUCTION: Antenatal corticosteroids (ACS) are recommended for pregnant persons at risk for imminent preterm delivery within 7 days. Many diagnosed with threatened preterm labor (tPTL) are given ACS but do not deliver until term. The objective of this study was to analyze characteristics of those seen for tPTL who receive ACS to better understand clinical decision-making.

METHODS: This retrospective cohort study consisted of patients seen in triage at an urban hospital caring for underserved patients in 2021 for tPTL during pregnancy. Demographic variables (maternal age, race and ethnicity, prior preterm delivery) and obstetric variables (cervical dilation, effacement, membrane rupture, tocolytic administration) were evaluated against the primary outcome of ACS administration.

RESULTS: Two hundred ninety pregnant people with 372 unique encounters for tPTL were identified. The mean gestational age at presentation was 33.5 weeks. 107 patients in 111 encounters received ACS, which was associated with lower body mass index (BMI), greater cervical dilation and effacement, membrane rupture, and more frequent contractions (all P<.01). Logistic regression, limited to first encounter in triage, found that BMI (odds ratio 0.91, 95% CI 0.87–0.95), cervical dilation 2 cm or greater (2.49, 1.12–5.35), and cervical effacement 50% or higher (4.80, 2.25–10.24) were significantly associated with patients receiving ACS. Forty-four percent of those receiving ACS delivered within 7 days, compared to 11% of those who did not receive ACS (P<.001).

CONCLUSION: Greater cervical dilation and effacement and a lower BMI were associated with ACS administration, although most patients receiving ACS did not deliver within 7 days. These findings will contribute to developing a clinical decision model for administering ACS.