The menstrual cycle is regulated by the complex interaction of 4 hormones: luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen and progesterone. But how do these hormones work and what happens with them during our cycle?

The first two, LH and FSH, are produced in the pituitary gland, a gland located in the brain, and are released into the bloodstream until they reach the ovary to stimulate the production and release of estrogen and progesteron, also called the female hormones. Estradiol is the hormone produced in the ovary during the first half of the cycle (proliferative phase), secondary to its stimulation by FSH. Progesterone is the hormone produced in the second half of the cycle (luteal phase) by the corpus luteum, a structure formed in the ovary after ovulation.

These four hormones play a very significant role during the menstrual cycle, increasing or decreasing depending on each moment of the cycle. 

From the beginning of the female cycle (first day of menstruation) and for approximately 7 days, FSH levels increase and stimulate the production of estrogen in the ovary, causing follicles to be selected and to increase in size. When the estrogen concentration is too high, it inhibits FSH production, causing a dominant follicle to be selected. This results in only one follicle growing in each cycle. Before ovulation, estrogen levels decrease again. 

LH maintains its production at low levels during the first half of the menstrual cycle and has its highest production around day 14 of the cycle, when its secretion increases tenfold, generating a peak that induces ovulation.

After ovulation, the corpus luteum begins to produce progesterone and levels increase during the second half of the cycle. This causes changes in the uterus, making it suitable for possible implantation in the event of fertilization.

LH and FSH production decreases in this second half of the cycle. Estrogen levels increase slightly again. At the end of the cycle, the decrease in LH causes estrogen and progesterone levels to decrease, resulting in endometrial shedding.  As estrogen and progesterone levels decrease, PMS symptoms may increase until the pituitary gland increases FSH and LH production again and the new cycle begins. Symptoms usually begin during the second half of the menstrual cycle. They usually disappear 1 to 2 days after the menstrual period begins.

Hormonal imbalance can affect this complex interaction between hormones, brain and reproductive organs. Healthy lifestyle habits (healthy and balanced diet and regular exercise), healthy environmental conditions (avoid stress and ensure a good night sleep)  and keeping blood glucose levels on a healthy range can help to maintain hormonal balance. By continuously measuring your blood glucose levels you can ensure stable insulin levels. 

Insulin plays a key role here. High insulin levels mix up ovary hormone production affecting the balance between estrogen, progesterone and testosterone. These imbalances affect female health, one of the first is that PMS symptoms may worsen or intensify. Many women experience more sugar cravings during PMS and have more fatigue and stress. 

Find your balance regulating your blood glucose levels with the help of a continuous glucose monitor (CGM) and Hello Inside.