The thyroid-stimulating hormone (TSH) and prolactin responses to
thyrotropin-releasing hormone (TRH), administered during the follicular and
luteal phases of the menstrual cycle, were examined in 14 women with
prospectively confirmed premenstrual syndrome and in nine control subjects.
There were no differences in basal or maximum increase in TSH or prolactin
values between menstrual cycle phases in patients or in control subjects or
between patients and control subjects in either phase. However, there was
significantly greater variability in TSH response to TRH among symptomatic
patients (seven of 10 patients: three with blunted and four with augmented
response) than among control subjects (none of nine patients).