What to Expect When Your Periods Become Unpredictable

Irregular or heavy bleeding during perimenopause is extremely common—but that doesn’t mean it should be ignored.

Perimenopause is a time of hormonal fluctuation and erratic ovulation, which can absolutely explain changes in cycle timing and flow. However, the key word is evaluation. The goal is to determine whether the bleeding is simply hormonal—or if there is something structural or more serious that needs attention.

Here’s how a thoughtful evaluation typically unfolds.

Step 1: A Detailed History

The most important diagnostic tool is still a thorough conversation.

We look at:

• Cycle frequency (Are they closer together? Further apart?)
• Flow (Are you soaking pads hourly? Passing clots?)
• Duration (More than 7–8 days?)
• Intermenstrual spotting?
• Post-coital bleeding?
• Pain or pressure symptoms?
• Medication use (including hormone therapy)
• Personal and family history of uterine cancer
• Risk factors such as obesity, diabetes, or hypertension

This helps determine whether bleeding patterns are consistent with ovulatory changes—or raise concern for other causes.

Step 2: Physical Exam

A pelvic exam allows us to assess:

• Uterine size (enlargement may suggest fibroids or adenomyosis)
• Cervical abnormalities
• Vaginal or vulvar sources of bleeding
• Signs of atrophy or infection

Not all bleeding comes from the uterus, so this step matters.

Step 3: Laboratory Testing

Depending on the presentation, labs may include:

• Pregnancy test (yes—even in perimenopause)
• CBC to evaluate anemia
• TSH to rule out thyroid dysfunction
• Iron studies if heavy bleeding has been ongoing
• Occasionally hormone levels (though these are often fluctuating and less diagnostic)

Hormone levels in perimenopause can vary widely, so they are not usually required to diagnose the transition itself.

Step 4: Pelvic Ultrasound

A transvaginal ultrasound is often the first-line imaging study. It helps evaluate:

• Endometrial thickness
• Fibroids
• Polyps
• Ovarian cysts
• Adenomyosis

In perimenopausal women, an endometrial lining that appears thickened or irregular may warrant further evaluation.

Step 5: Endometrial Biopsy

For women over 45—or younger women with risk factors—an endometrial biopsy is commonly recommended if bleeding is:

• Heavy and persistent
• Irregular and unpredictable
• Associated with a thickened lining on ultrasound
• Not responding to initial treatment

The purpose is to rule out endometrial hyperplasia or cancer. Most biopsies are reassuring—but performing one when indicated is critical.

When Is Bleeding “Just Hormonal”?

Perimenopausal cycles often become anovulatory, meaning ovulation does not occur consistently. Without ovulation, progesterone levels drop, allowing estrogen to stimulate the uterine lining unchecked. This can cause heavy, irregular shedding.

But “likely hormonal” is a conclusion we reach after appropriate evaluation—not before.

The Takeaway

Perimenopausal bleeding is common. It is often benign. But it should never be dismissed.

Evaluation is about reassurance as much as diagnosis. Once serious causes are ruled out, we can focus confidently on treatment options that reduce bleeding, protect the uterine lining, and improve quality of life.

If your cycles have changed and are affecting your daily functioning, it’s time for a conversation. Perimenopause is a transition—but suffering through it is not a requirement.

At Menopause Solutions, our experienced providers, Elaine Eustis, MD, FACOG, MSCP and Rhonda Leach, DNP, WHNP, MSCP are here to help women of the Charleston and Mt. Pleasant areas navigate through menopause and perimenopause.