At 42, several months without a period is most often perimenopause — the years-long transition where hormone levels become erratic before periods stop for good. But if you already live with an autoimmune condition (thyroid disease, lupus, or a similar diagnosis), that condition can also disrupt your cycle on its own, and it can accelerate ovarian ageing too. Your doctor typically needs to check for both rather than assuming one explains the other.

Why perimenopause is the reasonable first guess

Periods becoming irregular — skipping months, then returning, then skipping again — in your early-to-mid 40s is a normal and expected pattern as ovarian hormone production winds down unevenly. Cycles often lengthen before they stop altogether, and this stretch can genuinely last several years. Age alone makes perimenopause the statistically likely explanation for irregular or missed periods at 42.

Why an existing autoimmune condition changes the question

An autoimmune condition doesn't rule perimenopause out, but it adds two things a doctor has to check before treating the missed periods as "just" perimenopause:

  • Some autoimmune diseases affect the ovaries directly. Autoimmune conditions are associated with a higher likelihood of the ovaries running low on eggs earlier than average — sometimes called premature or early ovarian insufficiency — which can look identical to perimenopause on the surface but carries different long-term implications (including for bone and heart health) and is confirmed differently.
  • Some autoimmune conditions or their treatment affect periods through a separate pathway. Autoimmune thyroid disease is a common example — both an underactive and an overactive thyroid can cause missed or irregular periods independent of anything happening in the ovaries. Certain medications used for autoimmune conditions can also affect the cycle.

So the honest answer to "is this perimenopause or my autoimmune condition" is often "we need blood work to find out" — the two aren't mutually exclusive, and one can be layered on the other.

What your doctor will typically check

  • Hormone levels, including FSH and estradiol, which support a perimenopause or ovarian-insufficiency picture when repeatedly abnormal for your age.
  • A thyroid panel, since thyroid disease is both common and easily tested, and frequently coexists with other autoimmune conditions.
  • Prolactin, another common and treatable cause of missed periods that's simple to rule out.
  • A pregnancy test, regardless of age or how unlikely it seems, since it's the fastest thing to exclude.
  • A review of your autoimmune condition's activity and medications, since a flare or a recent medication change can itself shift your cycle.

A missed period at 42 with an autoimmune condition in the picture isn't a either/or question — it's usually answered by testing for both possibilities together, not choosing one explanation over the other.

When to seek care sooner rather than later

See your doctor without waiting if the missed periods come with hot flushes and night sweats severe enough to disrupt sleep, with new joint pain or another sign your autoimmune condition may be flaring, with unexplained weight change, or with any vaginal bleeding after twelve full months without a period — the last of these always needs prompt evaluation, at any age.

Frequently asked

Can an autoimmune condition cause early menopause?

Some autoimmune conditions are linked to a higher chance of the ovaries running low on eggs earlier than average, which can present like early menopause. This is confirmed with blood tests rather than assumed from the autoimmune diagnosis alone, and it's worth pursuing since the long-term care (including bone and cardiovascular protection) can differ from typical perimenopause managed on its own.

Does thyroid disease alone explain months without a period?

It can. An underactive or overactive thyroid is one of the more common, and most easily treatable, causes of missed or irregular periods — which is exactly why a thyroid panel is usually one of the first tests ordered, alongside hormone levels, when periods stop for several months.

If it turns out to be perimenopause, does the autoimmune condition need extra monitoring?

Possibly — ask your doctor specifically, since some autoimmune conditions warrant closer attention to bone density or cardiovascular risk once periods stop, and the right monitoring plan depends on which condition you have and how it's currently managed.

Should I wait a few more months before getting tested?

There's little benefit to waiting once you're several months in, since the blood work that clarifies the cause is straightforward and the same tests are needed eventually either way. Testing sooner also means any treatable cause — thyroid, prolactin, or a medication effect — gets addressed sooner.