ENORRHAGIA IS AN IMPORtant cause of ill health in women worldwide. A b o u t o n e t h i r d o f women report heavy menstrual bleeding at some time in their lives. 1 Menorrhagia is the presenting symptom among the majority of women who undergo hysterectomy, 2,3 and recent data suggest that menorrhagia is an increasingly common health problem. 4 The levonorgestrel-releasing intrauterine system (LNG-IUS) (Schering Co, Turku, Finland) has been advocated for the treatment of menorrhagia as an alternative to surgery. 5 The LNG-IUS is an intrauterine system that releases 20 µg of levonorgestrel every 24 hours over 5 years. The LNG-IUS was developed during the 1980s and licensed first for contraception in Finland in 1990. The estimated number of current LNG-IUS users worldwide is
The effects of season on the activity of the pituitary-ovarian axis and the pineal gland were studied in 11 women by serum and urinary melatonin determinations and in 21 women by measurements of the serum concentrations of anterior pituitary and ovarian hormones during the dark and light seasons. A melatonin index was determined by integration of the area below the curve of serum melatonin concentrations during 24-h periods in both seasons. During the dark season, the daytime 12-h melatonin index and daytime urinary melatonin excretion were significantly higher than during the light season. In addition, the duration of the nocturnal melatonin pulse (serum melatonin levels, greater than 65 pmol/L) was lengthened during this season, whereas the mean serum estradiol concentration was significantly decreased at the time of ovulation and during the luteal phase of the cycle, indicating lowered ovarian activity. Luteal phase gonadotropin concentrations were increased during the dark season, which was also characterized by increased sex hormone-binding globulin (SHBG) and decreased free testosterone concentrations and free androgen indices (ratio of testosterone to SHBG X 700) throughout the menstrual cycle. The dark season was thus characterized by increased melatonin secretion and decreased ovarian and androgenic activities. In summary, we characterized two season-dependent hormonal phenomena. Although we did not prove any cause and effect association between melatonin and anterior pituitary-ovarian hormones, the inverse seasonal relationship in pineal gland and ovarian secretion suggests that melatonin is causally related to reproduction in humans.
Abstract.
Serum melatonin concentrations from 55 pregnant healthy women (13 during the first, 18 during the second and 24 during the third trimester) and 11 non-pregnant control women were measured radioimmunologically at 11.00 h (Study A). In addition, serum melatonin concentrations from 12 women in early and 11 women in late pregnancy were measured every four hours throughout the day (Study B). Serum melatonin levels during the third trimester of pregnancy (76.5±38.3 pmol/l were significantly (p<0.01) higher than those during the first (29.7±9.9 pmol/l and the second trimester (39.1 ± 11.2 pmol/l and those of non-pregnant control women (41.7± 15.5 pmol/l and there was a positive correlation between the week of gestation and serum melatonin at 11.00 h (Study A). A clear diurnal rhythm in serum melatonin concentrations was found both in early and in late pregnancy (Study B). The amplitude and duration of the nocturnal rise of melatonin were higher during late pregnancy, but there was no clear phase shift. Increased serum concentration of melatonin in late pregnancy may be due to increased synthesis and secretion or retarded metabolism of melatonin during late pregnancy.
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