Eighty patients in India were included in the study «Acharya N, Acharya S, Shukla S ym. Gonadotropin le...»1, out of whom 46 (57.5 %) had subclinical hypothyroidism and 34 (42.5 %) had overt hypothyroidism. In subclinical hypothyroidism group the menstrual dysfunction was oligomenorrhea (28.2 %) followed by menorrhagia (17.4 %). 39.13 % had normal menstruation. In overt hypothyroidism group again it was oligomenorrhoea (23.5 %) which was the principal menstrual abnormality followed by menorrhagia (17.6 %). The percentage of females with normal menstruation was 47.1 %. The dominant menstrual abnormalities found in hypothyroid patients were menorrhagia and oligomenorrhoea. Menorrhagia was not defined and alkaline hematine method or PBAC was not used.
Krassas et al investigated «Krassas GE, Pontikides N, Kaltsas T ym. Disturbanc...»2 the menstrual history, starting 6 months before the discovery of the disease, in 171 female premenopausal hypothyroid patients and 214 normal controls, with similar age and body mass index (BMI) in Thessaloniki, Greece, Zajecar, Yugoslavia and Athens, Greece. Of the 171 hypothyroid patients, 131 (76,6 %) had regular cycles and 40 (23,4 %) irregular periods, and of those with irregular periods, 12 (30 %) had menorrhagia and 17 (42,5 %) had oligomenorrhoea. Out of 214 normal controls, 196 (91,6 %) had normal menstruation and 19 (8,4 %) irregular cycles. The latter group included 12women with oligomenorrhoea and 2 women with menorrhagia. The number of patients with hypermenorrhea and menorrhagia in the hypothyroid groupdecreased with levothyroxine treatment from 12 to 3.
The writers discuss that one of the earliest reports in the literature, Goldsmith et al. (1952) «GOLDSMITH RE, STURGIS SH, LERMAN J ym. The menstru...»3, found that 8 out of 10 patients with primary myxoedema had menstrual disturbances. Specifically, one patient had amenorrhoea, 5 had clinical metropathia hemorrhagica and 2 had menorrhagia. Benson & Dailey (1955) studied the menstrual pattern in hyperthyroidism and subsequent posttherapy hypothyroidism. Menorrhagia, polymenorrhoea or both, were noted in 18 (58,6 %) of 31 women during the period of decreased thyroid function subsequent to specific therapy for hyperthyroidism. Scott & Mussey (1964) «SCOTT JC Jr, MUSSEY E. MENSTRUAL PATTERNS IN MYXED...»4 found that 28 (56 %) out of 50 hypothyroid patients had menstrual irregularities, mainly metrorrhagia or menorrhagia, alone or combined.
Comments
We still do not know what the prevalence of thyroid dysfunction is among women of fertile age with regular heavy menstrual bleeding but no signs or symptoms of thyroid disease. The weakness of all the studies is the lack of clear definition of menorrhagia with no use of for example PBAC or alkaline haematine method for evaluating the amount of bleeding. In the earlier studies from 1952 and 1964 the prevalence of menstrual disturbances was high compared to recent studies. Krassas (1999) found that menstrual irregularities tend to be more frequent in severe hypothyroidism in comparison to mild cases in premenopausal women. It could be that modern practices diagnose hypothyroidism earlier and in less severe form and this contributes to finding less menstrual disturbances in the more recent studies. There is a link between hypothyroidism and heavy menstrual bleeding. It is not known to what extent hypothyroidism is the only cause of menorrhagia.