Perimenopause, the transitional period before menopause, and is marked by hormonal fluctuations, irregular periods, and other physical, cognitive, and emotional symptoms. Some common signs include: Changes in menstrual flow and cycle length, Sudden estrogen surges, Sleep disturbances, and Vaginal dryness.
 
If you have a persistent change of seven days or more in the length of your menstrual cycle, you may be in early perimenopause. If you have a space of 60 days or more between periods, you're likely in late perimenopause.
 
Perimenopause is a natural process caused when your ovaries gradually stop working. Ovulation may become erratic and then stop. The menstrual cycle lengthens, and flow may become irregular before your final period. Symptoms are caused by the changing levels of hormones in the body, hot flashes, insomnia, and other physical and emotional symptoms.
 
Hot flashes are changes in the brain's thermoregulatory center and hormones with sudden, temporary feelings of warmth and sweating that usually affect the face, neck, and chest. They can also cause redness, increased heart rate. Hot flashes can last from 30 seconds to five minutes and can be mild, moderate, or severe. If you lose too much body heat, you might feel chilled afterward. Hot flashes that occur at night are called night sweats and can disrupt sleep. 
 
Factors that can increase the frequency or length of hot flashes include:
 
Obesity
Low levels of estradiol or progesterone
Smoking
Stress, depression, or anxiety