What is Perimenopause and When Does it Occur?

Lilli Link, MD
Medically Reviewed
January 27, 2021

What is perimenopause and when does it occur?

Perimenopause is the time that leads up to menopause, which is when a female’s menstrual period ends entirely (marked by 12 consecutive months without a period). It is also when many new hormonal symptoms can surface such as trouble sleeping , weight gain, irritability, and mood swings.

When the body approaches perimenopause it has fewer follicles producing estrogen (or the follicles are less viable) and the lack of estrogen prevents ovulation from occurring. This creates one of the hallmark symptoms of perimenopause: irregular periods . A period may disappear for a cycle or two, or your bleeding may appear closer together or farther apart. You may also have menstrual cycles in which your ovaries don’t release an egg (in other words, you don’t ovulate). And without ovulation, there isn’t an increase in progesterone, which typically follows ovulation.

In perimenopause, progesterone is typically the first hormone to drop. Progesterone plays a major role in stress management and the reduction of anxiety . Progesterone promotes gamma-aminobutyric (GABA) receptor production in the brain, which is the calming neurotransmitter. And the lower progesterone levels are, the more we are prone to irritability and anxiety. Lower progesterone levels may also cause sleep disturbances because of a lack of this calming hormone.

Estrogen dominance is also common during perimenopause, given that progesterone levels usually drop before estrogen levels. And estrogen levels during perimenopause may also fluctuate, becoming erratic and unpredictable. Because estrogen levels may not be high, but because progesterone levels are low, the ratio of these hormones tricks the body into thinking estrogen levels are too high. Symptoms of estrogen dominance are bloating or puffiness, irritability, heavy periods, breast tenderness, and weight gain (especially around the hips, buttocks, and thighs).

As perimenopause continues, and estrogen levels fluctuate, symptoms of estrogen deficiency may also surface: hot flashes, night sweats, vaginal dryness, depression, fatigue , poor memory, brain fog , decreased concentration, stress incontinence, and decreased libido.

Lilli Link, MD

Dr. Lilli Link is a board-certified Internist and Functional Medicine Practitioner who graduated from medical school at the University of Chicago, and completed her residency at Columbia Presbyterian Medical Center in New York.

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