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CME Credit Offered
CME Credit Offered
Abstract Award
Abstract Award

Poster Session 1

(260) Subclinical hypothyroidism in pregnancy: assessment of severe maternal morbidity

Thursday, January 30, 2025
10:30 AM - 12:30 PM  

    Submitting Author and Presenting Author(s)

  • Laurel S. Aberle, MD

    Resident
    LAGMC + USC OBGYN
    Los Angeles, CA, United States

    • Coauthor(s)

  • KB

    Katherine Bayard

    LAGMC + USC OBGYN
    Los Angeles, California, United States

  • JY

    Jennifer Yao, BA

    Keck School of Medicine, University of Southern California
    Los Angeles, California, United States

  • SM

    Shinya Matsuzaki, MD, PhD

    Division of Gynecologic Oncology, Department of Obstetrics and Gynecology
    Osaka University Graduate School of Medicine
    Osaka, Osaka, Japan

  • RM

    Rachel S. Mandelbaum, MD

    University of Southern California/Los Angeles General Medical Center
    Los Angeles, California, United States

  • JO

    Joseph G. Ouzounian, MBA, MD

    Professor and Chair of Obstetrics & Gynecology
    University of Southern California/Los Angeles General Medical Center
    Los Angeles, California, United States

  • KM

    Koji Matsuo, MD, PhD

    University of Southern California/Los Angeles General Medical Center
    Los Angeles, California, United States

Objective: To assess the association between subclinical hypothyroidism and severe maternal morbidity at delivery.

Study Design: This cross-sectional study queried the Healthcare Cost and Utilization Project's National Inpatient Sample. The study population included 21,517,317 delivery hospitalizations from 2016-2021. Subclinical hypothyroidism was identified with the World Health Organization’s International Classification of Disease 10th revision code of E02. Severe maternal morbidity followed the Centers for Disease Control and Prevention definition (20 indicators). Multivariable log-Poisson generalized linear model was created to examine the association of subclinical hypothyroidism and severe maternal morbidity.

Results:

A total of 11,885 patients had a diagnosis of subclinical hypothyroidism, corresponding to 5.5 per 10,000 or one in 1,810 deliveries. Older maternal age, White / Asian race, hypertensive disorder (pregestational, gestational, and pre-eclampsia), diabetes mellitus (pregestational and gestational), obesity, asthma, fetal growth restriction, and early preterm delivery (< 34 weeks) were associated with subclinical hypothyroidism in multivariable analysis. After controlling for clinico-obstetric factors, subclinical hypothyroidism was independently associated with an increased risk of severe maternal morbidity at delivery (185.1 vs 81.1 per 10,000, adjusted-odds ratio [aOR] 1.48, 95% confidence interval [CI] 1.33-1.64). Among the individual indicators, the risk of eclampsia (25.2 vs 7.8, aOR 3.18, 95%CI 2.22-4.55), pulmonary edema (25.2 vs 7.0, aOR 2.34, 95%CI 1.63-3.34), and acute respiratory distress syndrome (29.4 vs 12.3, aOR 2.08, 95%CI 1.49-2.90) were particularly increased among patients with subclinical hypothyroidism (all, aOR >2.00).

Conclusion:

The results of this contemporaneous nationwide assessment suggest that subclinical hypothyroidism may be associated with an increased risk of severe maternal morbidity at delivery. Whether or not universal thyroid testing in early pregnancy and treatment improve outcome in at risk-populations warrants further evaluation prospectively.