Subclinical Hypothyroidism among Pregnant Women with First Trimester Pregnancy Loss

Background: Subclinical hypothyroidism, defined by elevated thyroid-stimulating hormone levels with normal free thyroxine, is prevalent in pregnancy and has been associated with adverse outcomes, including first-trimester pregnancy loss. Aim and objectives: This study aimed to evaluate the impact of subclinical hypothyroidism on women experienced spontaneous miscarriage at first trimester.
Patients and methods: This case-control investigation has been performed on one hundred pregnant women recruited from The Outpatient (Antenatal Care Clinic) and Emergency Room at El Sahel Teaching Hospital through the period from March 2024 to February 2025. They were divided into two groups: Group A (Miscarriage group): 50 women presented with first trimester spontaneous miscarriage either missed, anembryonic sac, inevitable, complete, or incomplete miscarriage diagnosed by ultrasound or clinically and group B (Control group): 50 women with healthy viable pregnancy of gestational age < 20 weeks. Results: There was a significant variance among both groups as regards thyroid profile where group A had significantly greater TSH levels compared to group B (P < 0.001). There was a significant variance among both groups as regards the prevalence of subclinical hypothyroidism, which was significantly higher in group A compared to group B.
Conclusion: Subclinical hypothyroidism throughout pregnancy has been related to several negative maternal outcomes and may elevate the risk of first-trimester pregnancy loss. Early intervention with LT4 therapy, especially in women with higher TSH levels, may mitigate this risk. Further studies are warranted to establish definitive treatment.