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Menstrual disturbances in thyrotoxicosis
G E Krassas1, N Pontikides, T Kaltsas
1Endocrine Clinic, Panagia Hospital, Thessaloniki, Greece.
Clinical Endocrinology
|May 1, 1994
Summary
Hyperthyroidism in women is less likely to cause menstrual irregularities than previously thought. Smoking and higher thyroxine (TT4) levels are linked to irregular periods in thyrotoxicosis.
Area of Science:
- Endocrinology
- Reproductive Health
Background:
- Textbook information suggests hyperthyroidism frequently causes menstrual abnormalities like hypomenorrhea, oligomenorrhea, or amenorrhea in women.
- Clinical observations in a thyroid clinic indicated a lower incidence of menstrual disturbances among hyperthyroid patients.
Purpose of the Study:
- To accurately define the prevalence and characteristics of menstrual abnormalities in women with hyperthyroidism.
- To investigate the association between menstrual irregularities, smoking habits, body mass index (BMI), and thyroid hormone levels in thyrotoxicosis.
Main Methods:
- A case-control study involving 214 premenopausal women with thyrotoxicosis and 214 matched controls.
- Menstrual history, smoking status, and body mass index (BMI) were recorded.
- Radioimmunoassay was used to measure total thyroxine (TT4) and total triiodothyronine (TT3) levels.
Main Results:
- Only 21.5% of hyperthyroid patients experienced irregular menstrual cycles, contrasting with textbook claims.
- Smoking was significantly more common in patients with irregular periods (50%) compared to those with regular cycles (19%).
- Higher TT4 levels were observed in patients with menstrual disturbances (267.7 +/- 66.9 nmol/l) compared to those with normal cycles (240.6 +/- 47.6 nmol/l).
Conclusions:
- Hyperthyroidism is associated with menstrual abnormalities less frequently than previously reported, with no cases of amenorrhea observed.
- Smoking and elevated TT4 levels are significant factors contributing to menstrual disturbances in women with thyrotoxicosis.