# Risk factors associated with gestational transient thyrotoxicosis and their effects on the pregnancy course

## TL;DR

This study examines the risk factors and outcomes of gestational transient thyrotoxicosis in pregnant women, finding no serious complications.

## Contribution

The study provides new insights into the electrocardiogram findings in gestational transient thyrotoxicosis, not previously detailed.

## Key findings

- Thyroid-stimulating hormone levels normalized by an average gestational age of 18.3 weeks.
- No significant increase in serious obstetric complications like preeclampsia or gestational diabetes was observed.
- Electrocardiograms showed mostly sinus rhythm with no life-threatening arrhythmias detected.

## Abstract

To investigate the clinical characteristics of patients with gestational
transient thyrotoxicosis and its possible impacts on pregnancy.

This retrospective study included pregnant women with gestational transient
thyrotoxicosis who were admitted to our endocrinology outpatient clinic from
June 2020 to March 2023. Patients with other causes of thyrotoxicosis, such
as Graves’ disease, toxic nodular goiter, and subacute thyroiditis, were
excluded.

The study included 50 pregnant women who met the inclusion criteria and whose
data could be accessed. Two pregnant women were diagnosed with gestational
diabetes, and two pregnancies resulted in abortion. We observed that
thyroid-stimulating hormone levels normalized to euthyroid values at a mean
gestational age of 18.3 ± 3.7 weeks. The mean gestational age at
birth was 38 ± 1.8 weeks. The frequency of preterm labor, defined as
delivery before 37 weeks, was 10% (n = 5). Sinus rhythm was observed in 87%
of the electrocardiograms obtained during thyrotoxicosis, while sinus
tachycardia was detected in four and sinus arrhythmia in two cases. Thyroid
nodules were observed in 23 (47.9%) of 48 cases in which ultrasonography was
performed during thyrotoxicosis. Discussion: This retrospective study,
including 50 pregnant women with gestational transient thyrotoxicosis, found
no increase in the rate of serious obstetric complications such as
eclampsia/preeclampsia, gestational diabetes, preterm labor, or abortion.
Notably, in a detailed examination of electrocardiograms, which has not been
done in previous studies, we did not detect any serious, life-threatening
arrhythmias, although tachycardia was observed.