Prevalence and Pattern of Thyroid Dysfunction Among Women of Reproductive Age With Abnormal Uterine Bleeding: A...

Introduction Abnormal uterine bleeding (AUB) is a common gynecological condition that adversely affects the quality of life of women of reproductive age. Thyroid dysfunction is a recognized but often underdiagnosed non-structural endocrine cause of AUB that may be amenable to medical treatment. This study aimed to determine the prevalence and pattern of thyroid dysfunction among reproductive-aged women with AUB and evaluate its association with demographic characteristics, body mass index (BMI), thyroid hormone profile, and International Federation of Gynaecology and Obstetrics (FIGO) menstrual bleeding patterns. Methodology This prospective observational study was conducted among 150 reproductive-aged women (18-45 years) presenting with AUB at a tertiary care hospital in North India. Consecutive sampling was used for participant enrolment. Women with structural causes of AUB were excluded after clinical evaluation and ultrasonography according to the FIGO PALM-COEIN classification. Thyroid function was assessed using serum thyroid-stimulating hormone (TSH), total triiodothyronine (T3), and total thyroxine (T4). Participants were categorized into euthyroid and thyroid dysfunction groups, and clinicodemographic characteristics, BMI, thyroid hormone profiles, and menstrual bleeding patterns were compared. Multivariable binary logistic regression was performed to identify factors independently associated with thyroid dysfunction and menorrhagia. Results Thyroid dysfunction was identified in 45 of 150 women (30.0%). Overt hypothyroidism was the most common subtype (19/45, 42.2%), followed by subclinical hypothyroidism (16/45, 35.6%) and overt hyperthyroidism (10/45, 22.2%). No cases of subclinical hyperthyroidism were identified. Thyroid dysfunction was significantly associated with age >30 years (p = 0.044) and BMI ≥25 kg/m² (p < 0.001). On multivariable analysis, BMI ≥25 kg/m² remained independently associated with thyroid dysfunction (aOR, 33.33; 95% CI, 12.35-90.91; p < 0.001), whereas age >30 years was not (aOR, 2.18; 95% CI, 0.79-6.02; p = 0.135). Women with thyroid dysfunction had significantly higher mean serum TSH levels than euthyroid women (6.20 ± 4.89 vs. 2.54 ± 0.96 mIU/L; p < 0.001), whereas T3 and T4 levels were comparable. Significant associations were observed between thyroid dysfunction subtypes and FIGO menstrual bleeding patterns (p < 0.001), with menorrhagia predominating in overt hypothyroidism and polymenorrhagia in subclinical hypothyroidism and overt hyperthyroidism. On multivariable analysis adjusted for age and BMI, women with thyroid dysfunction were significantly less likely to present with menorrhagia compared to euthyroid controls (aOR, 0.06; 95% CI, 0.02-0.20; p < 0.001). Conclusion Thyroid dysfunction was common among women of reproductive age presenting with AUB and was significantly associated with BMI ≥25 kg/m² and distinct menstrual bleeding patterns, while the association with age was not sustained after adjustment. Thyroid function testing, particularly serum TSH estimation, should be considered in the evaluation of selected women with AUB based on clinical suspicion and guideline-based evaluation, rather than universal screening, to facilitate early diagnosis and appropriate management of reversible endocrine causes and support individualized treatment decisions.