Written by Dr. Caledonia Buckheit. Dr. Buckheit became a Menopause Society Certified Provider earlier this fall.
Ovarian Reserve and the Reproductive Lifespan
To understand perimenopause and how hormone therapy can help, you first have to understand some basics about the ovary and the female reproductive lifespan. Those of us with ovaries are born with all the eggs we will ever have. At around 20 weeks gestation—when we are still inside our mother’s womb—the number of eggs begins to decline. At this midpoint in fetal development, the ovaries contain 6–7 million eggs, but by birth only 1–2 million remain. These are the eggs responsible for carrying us through our entire reproductive life until menopause.
Ovarian reserve continues to fall throughout life, regardless of ovulation. Each month, a cohort of eggs dies off. This is true whether someone takes birth control, undergoes ovarian stimulation for egg retrieval, or any number of factors. By puberty, only 300,000–400,000 eggs remain. Age is the biggest factor in this predictable decline, though chemotherapy and radiation can also accelerate egg loss.
What Happens During Perimenopause?
The average age of natural menopause is 51 for women in the US. But the symptoms most people think of as “menopause symptoms” actually begin earlier—during perimenopause, the transitional years leading up to menopause.
As egg reserve declines, hormonal signaling within the ovary changes. Estrogen production becomes inconsistent rather than predictable, and the brain hormones responsible for stimulating the ovary (FSH) and triggering ovulation (LH) become chronically elevated. This creates a state known as compensated ovarian failure. For years, the ovaries continue functioning in this erratic pattern until the remaining eggs are gone. This is perimenopause.
During compensated ovarian failure, supplementing estrogen and progesterone can provide negative feedback to the brain and steady background hormone levels that greatly improve symptoms. However, this doesn’t mean periods or ovulation stop. In fact:
- Periods often become heavier, more irregular, and more symptomatic.
- Ovulation becomes unpredictable—and sometimes doesn’t happen at all.
- Pregnancy is still possible, and the risk of twins is actually higher during this time.
The Biggest Challenges of Treating Perimenopause
This brings us to the two biggest challenges of treating perimenopause:
1. What do we do about the periods?
2. How do we prevent pregnancy?
A good perimenopause hormone therapy plan must manage periods and ensure reliable contraception—if pregnancy is a risk.
If pregnancy isn’t a concern—because you’re not sexually active, have permanent sterilization, or don’t have a uterus—the focus is on estrogen replacement and cycle regulation.
In these cases, a continuous estrogen product (pill, patch, gel) plus cyclic oral progesterone (if needed) can work very well. The estrogen helps symptoms, and the cyclic progesterone forces a predictable withdrawal bleed, whether or not you ovulate. Daily progesterone with continuous estrogen is another option, though breakthrough bleeding can be more common.
If pregnancy is a possibility, a progesterone-containing IUD (Mirena or Liletta are best) plus systemic estrogen is an excellent solution. The IUD keeps the uterine lining thin—meaning light or absent periods—while estrogen manages symptoms. Another strategy is Slynd (a progesterone-only pill) taken daily, plus an estrogen product. And of course, combined hormonal birth control pills can provide both reliable contraception and stable daily hormones to keep the perimenopause chaos in check.
When Changing Periods Need a Workup
Although irregular periods are common during perimenopause, new or significantly different bleeding should always be evaluated. Remember:
- You can be in perimenopause AND have structural problems like uterine polyps or fibroids.
- Perimenopause can coexist with endocrine disorders that can also impact periods.
- Endometrial hyperplasia or cancer becomes more common with age and higher body weight.
This is why a high index of suspicion is essential. A typical evaluation may include an exam, labs, ultrasound, and sometimes an endometrial biopsy.
If we’ve ruled out other causes and bleeding remains disruptive, several surgical options can help. The following treatments are highlighted for their particular benefits in the setting of hormone therapy:
- Endometrial Ablation: A minimally invasive procedure that treats heavy bleeding by thinning or destroying the uterine lining.
- Hysterectomy: Addresses the period problem and eliminates pregnancy risk entirely. Bonus: After hysterectomy, estrogen-only hormone therapy becomes an option—which has a very favorable safety profile in most people.
These procedures can be especially beneficial for those whose perimenopause symptoms and bleeding patterns are severely impacting quality of life.
You Don’t Have to Suffer Through Perimenopause
Perimenopause is a normal, expected transition—but the hormonal fluctuations that come with it can be profoundly disruptive. Understanding what’s happening in the ovaries can make the symptoms feel less mysterious and more manageable. With the right treatment plan, most people find significant relief. And for those whose bleeding patterns become unmanageable, procedural options can offer long-term solutions. The bottom line: you don’t have to white-knuckle your way through perimenopause. There are safe, effective, personalized treatments that can make these years far more comfortable and predictable.
