Dear lelo: My best GUESS is that you are having a premenstrual flare of a low level yeast infection. Here is a citation on this from the National Library of Medicine site:
Am J Obstet Gynecol. 1997 Jun;176(6):1376-80.
The impact of contraceptive methods on the onset of symptomatic vulvovaginal candidiasis within the menstrual cycle.
Nelson AL.
Source
Department of Obstetrics and Gynecology, Harbor-University of California, Los Angeles, Medical Center, Torrance 90509, USA.
Abstract
OBJECTIVE:
Vulvovaginal candidiasis is the second most common cause of vaginal discharge. Low-dose oral contraceptives are no longer thought to increase the absolute risk of episodic vulvovaginal candidiasis. This study investigates the possible impact that hormonal contraception may have on the timing of onset of symptoms within the menstrual cycle.
STUDY DESIGN:
In a retrospective chart review of reproductive-aged women seen at the Women's Health Care Clinic at Harbor-University of California, Los Angeles, Medical Center, data from the records of 448 symptomatic women who had 507 episodes of vulvovaginal candidiasis were extracted and analyzed for timing of onset of symptoms within the menstrual cycle. Diagnosis was based on symptoms, physical findings, and microscopy. Onset was divided into five physiologic ranges within an idealized 28-day menstrual cycle. Comparisons among groups were made with use of chi 2 and p < 0.05 thresholds for statistical significance.
RESULTS:
No differences were found in the onset of symptoms within the idealized menstrual cycle ranges between women using hormonal birth control methods and those using nonhormonal ones. The distribution was remarkably uniform throughout the cycle
with the exception of the first few days (during menses).
As you can note lelo, yeast infections were more likely to occur around the time of menses. Your best bet is to see your GYN or clinic at the time when the symptoms are going to be the worst. If yeast is present by wet mount microscope test, or culture or other test, the GYN might recommend preventative treatment. In this scenario, a short course of yeast treatment is given in the premenstrual week (could be oral pill or topical cream/suppository). After six months this is stopped to see if the yeast cycle has halted.
Yours,
Jane