715: The association between thalassemia trait and preterm delivery

Abstract

YVONNE CHENG, ALLISON BRYANT, AARON CAUGHEY, University of California, San Francisco, San Francisco, California OBJECTIVE: To examine whether the presence of alpha or beta thalassemia trait is protective against preterm delivery. STUDY DESIGN: This was a retrospective cohort study of women with live, singleton, non-anomalous pregnancies delivered at a single academic institution. The diagnosis of thalassemia trait was based on clinical laboratory testing. The primary outcome was preterm delivery ( 37 weeks). Gestational age at delivery between women with and without thalassemia trait was examined by survival analysis, with log-rank test to compare Kaplan-Meier survival curves. Chi-square test was used to examine categorical variables, with p 0.05 as the cut-off for statistical significance. RESULTS: Of 39,856 women who met study criteria, 81 (0.21%) women were diagnosed with alpha-thalassemia trait and 327 (0.82%) women had beta-thalassemia. The rate of preterm delivery ( 37 weeks) was 5.8 % in women with a diagnosis of beta-thalassemia trait, compared to 10.2% in women without a diagnosis of beta-thalassemia trait (p 0.01). The protective effect of beta-thalassemia trait was also demonstrated by Kaplan-Meier survival curves (p 0.01 by log-rank test, Figure). However, alpha-thalassemia trait was not associated with a lower rate of PTD (10.1% vs 9.9%, p 0.94).