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Poster Session 4

Category: Physiology/Endocrinology

Poster Session 4

(1260) Beyond the Threshold: Clinical Implications of Subclinical Hypothyroidism in Pregnancy

Thursday, February 12, 2026

3:30 PM - 5:00 PM

Submitting Author and Presenting Author(s)

Shir Zagdon Keidar, MD (she/her/hers)

Resident in Obstetrics and Gynecology
Soroka University Medical Center, Ben-Gurion University of the Negev
Beer sheva, HaDarom, Israel

Coauthor(s)

NB

Nitzan Burrack, BSc

Student & Data Analyst, Clinical Research Center, Soroka University Medical Center
Clinical Research Center, Soroka University Medical Center; Faculty of Health Sciences, Ben‑Gurion University of the Negev
Beer sheva, HaDarom, Israel
MF

Merav Fraenkel, MD

Head of the Endocrinology Unit
Endocrinology Unit, Soroka University Medical Center; Faculty of Health Sciences, Ben‑Gurion University of the Negev, Be’er Sheva, Israel
Beer sheva, HaDarom, Israel
UY

Uri Yoel, MD

Senior Physician in the Endocrinology Unit, Soroka University Medical Center
Endocrinology Unit, Soroka University Medical Center; Faculty of Health Sciences, Ben‑Gurion University of the Negev, Beer‑Sheva, Israel
Beer sheva, HaDarom, Israel
Tamar Eshkoli, MD

Senior
Soroka Medical Center, Ben Gurion University of the Negev
beer sheba, HaDarom, Israel

Objective:
To evaluate pregnancy complications in women with subclinical hypothyroidism (mean TSH 4–10 mIU/L) using a cross-sectional study.

Study Design:
Data from 95,632 live birth pregnancies (2013–2022) were analyzed using the Clalit Health Services (CHS) database. The study included CHS-insured women aged ≥18 years with available TSH results during pregnancy. Subclinical hypothyroidism was defined as a mean TSH between 4 and 10 mIU/L without a diagnosis of overt hypothyroidism. The euthyroid reference group consisted of women with TSH < 4 mIU/L and no history of hypothyroidism or levothyroxine use. Women with subclinical hypothyroidism were matched to euthyroid controls using propensity score-based matching, adjusting for maternal age, ethnicity, socioeconomic status, IVF, recurrent pregnancy loss, and smoking. Pregnancy complications were compared using descriptive statistics, univariate analysis, and quasi-Poisson regression.

Results:
The final analysis included 8,697 subclinical hypothyroid and 86,935 euthyroid pregnancies with similar baseline characteristics. Women with subclinical hypothyroidism had slightly higher rates of severe preeclampsia (1.5% vs. 1.1%, p< 0.001), cesarean delivery (21.2% vs. 18.7%, p< 0.001), preterm birth (8.3% vs 7.3%, p< 0.001), assisted delivery (6.3% vs. 5.1%, p< 0.001), and low birth weight (9.3% vs. 7.9%, p< 0.001). No significant differences were observed in rate of gestational hypertension, gestational diabetes, or postpartum hemorrhage. In multivariable analysis, subclinical hypothyroidism was associated with a modestly increased risk of pregnancy complications (IRR 1.07, 95% CI 1.04–1.11; p< 0.001).

Conclusion:
Subclinical hypothyroidism was associated with a small but statistically significant increase in adverse pregnancy outcomes, supporting the need for heightened surveillance and individualized clinical consideration during pregnancy.