Serum gonadotrophins, prolactin and ovarian steroids in primary dysmenorrhoea.

Serum samples were collected from 27 women with incapacitating primary dysmenorrhoea and from 16 normal women in the early part of the cycle (between day 3 to 6), at midcycle (between days 13 to 16) and in the late part of the cycle (between days 23 to 26) for determination of FSH, LH, prolactin (PRL), 17 beta-oestradiol (E2) and progesterone (P). The gonadotrophin and P levels showed normal and similar ovulatory patterns in both groups. The PRL concentrations (mean +/- SD) in dysmenorrhoeic women were lower than normal in the early part (9.2 +/- 4.0 ng/ml vs 14.5 +/- 7.3 ng/ml, p less than 0.01) and in the late part of the cycle (11.7 +/- 5.2 ng/ml vs 16.5 +/- 10.2 ng/ml, p less than 0.05), but not so at midcycle (9.1 +/- 2.8 ng/ml vs 10.4 +/- 4.4 ng/ml, p greater than 0.05). The E2 level was higher than normal in dysmenorrhoeic women in the late cycle (163.0 +/- 76.7 pg/ml vs 93.3 +/- 64.3 PG/ML, p less than 0.01), but apart from this the ratio of E2/P did not differ between the groups. These hormonal changes may be related to an excessive production of endometrial prostaglandins in primary dysmenorrhoea.