The Role of the Thyroid Gland
The health of the thyroid gland should be considered in any debility in the reproductive organs. Hypothyroidism can be the primary causative agent in abnormal Pap smears (Papanicolaou test), menorrhagia (abnormally heavy or long menstrual periods), ovarian cysts, metrorrhagia (bleeding other than that caused by menstruation), infertility, and unsuccessful pregnancies. Fibroid tumors are rare in women with hypothyroidism who have been maintained on adequate thyroid therapy. It is possible to produce fibroids in experimental animals by injections of estrogen, and there is evidence of excess estrogens in women with hypothyroidism.
In hypothyroidism, there is increased activity of the pituitary gland aimed at trying to stimulate the thyroid to produce more hormone secretions, and increased pituitary activity may cause the ovaries to increase their estrogen output. Unless the health of the thyroid is considered in assessing any "female" complaint, the individual may be at risk for unnecessary physical suffering and emotional debility. A few grains of thyroid extract can often reverse impending disaster in the reproductive tract. The importance of a thyroid evaluation by a competent endocrinologist cannot be overemphasized.
Interestingly, women with endometriosis and antithyroidal antibodies have significantly higher values of polychlorinated biphenyls (PCBs) (Gerhard 1992). PCBs represent a family of more than 200 structurally related chemicals that were once used as industrial coolants in power transformers. Because PCBs were found to cause cancer in laboratory animals, their use has been banned for more than 20 years in the United States. However, PCBs still persist in the environment and mimic the action of thyroxin, a hormone produced by the thyroid gland. It is thought that PCBs affect not only the thyroid gland, but also the reproductive system in animals.
The luteinizing hormone (LH), responsible for ovulation, and the follicle-stimulating hormone (FSH), responsible for follicle maturation, respond to stimuli from gonadotropin-releasing hormone (GnRH) released from the hypothalamus. When a GnRH analogue (GnRHa) was given as leuprolide acetate, significant tumor reduction was achieved (Golan 1996). In another study, non-menopausal women (110, with mean age of 42.1 years) with symptomatic uterine leiomyomata (smooth benign fibroid tumors) were studied to determine the efficacy of leuprolide, administered intramuscularly at a dose of 3.75 mg every 4 weeks for 16 weeks. Initial results revealed that the uterine size decreased to 50% of its original volume in 33 (37.5%) of 88 women who entered the study with a hypertrophic uterus. Eighty fibromas, measured separately, decreased by greater than 50% of the initial size in 47 (52.8%) of the women tested (Serra 1992). Amenorrhea (or absent menstrual periods) and an attendant increase in hemoglobin levels were produced by way of the GnRH inhibitor.
Because of cost and side effects (hot flashes being the major complaint followed by isolated incidences of hypertension and headache), continued use of GnRH inhibitors is often considered prohibitive. But important correlations may be taken from GnRHa research that relates to the thyroid gland. What leuprolide is accomplishing by way of inhibition of LH and FSH, hypothyroidism may be undoing by stimulating these hormones into greater activity.
In a condition of hypothyroidism, the thyrotropin-releasing factor, elaborated in the hypothalamus, is continually being secreted to arouse greater thyroid activity from the anterior pituitary. The body may not allow for thyroid hormone stimulation without stimulation of LH and FSH as well. The thyrotropin-releasing factor may arouse other areas in the anterior pituitary in its effort to goad the production of increased thyroid hormone release.
GnRH is capable of inciting additional production from both LH and FSH which in sequence stimulate the uterus. A reduction in GnRH can actually diminish fibroid size and symptoms. It is likely that the thyrotropin-releasing factor can elicit a similar stimulatory effect on LH and FSH. The anterior pituitary secretes the growth hormone, thyrotropin, adrenocorticotropic hormone, melanocyte-stimulating hormone, FSH, LH, prolactin, and endorphins. This cascade likely best describes why hypothyroidism is the purveyor of so many reproductive tract anomalies and why it must be considered in any treatment protocol.
Obtaining satisfactory laboratory results regarding thyroid performance is sometimes difficult. This unfortunate situation has led alternative practitioners to resort to temperature analysis to demonstrate thyroid function. This is a noninvasive, reliable test that can highlight the need for thyroid support. Sometimes a glass-bulb thermometer is used under the arm. At other times, physicians monitor the readings via the traditional sublingual method. Consistent readings below 97.6°F are suggestive of an underactive thyroid gland.