Perimenopause at 38: Earlier Than You Expected, but Not as Rare as You Think

You're 38 years old and something has shifted. Your periods are different. Your sleep feels unpredictable in a new way. Your mood swings arrive harder and leave slower. You've mentioned it to your doctor and gotten a raised eyebrow, a reassurance that you're "too young," or a suggestion that it's probably just stress.

You're not imagining it. And you're not too young.

Perimenopause most commonly begins in the mid-to-late 40s, but a meaningful percentage of people start the transition in their late 30s. It's earlier than the average, and that's worth acknowledging. But "earlier than average" is very different from "impossible" or "something is wrong with you." For some people, the ovaries simply begin their transition sooner. This is your biology, not a failure.

What perimenopause actually means at this age

Perimenopause is the transition period before your final menstrual period. It can last anywhere from a few years to more than a decade. During this time, estrogen and progesterone levels stop following their predictable monthly rhythm and begin fluctuating more erratically.

At 38, if perimenopause is beginning, you are likely in what's called the early menopausal transition. This stage is characterized by subtle but real changes: cycles that are still mostly regular but have started shifting in length, PMS that feels more intense or different in character, and new symptoms that don't line up with anything else in your life.

This is not the same as premature ovarian insufficiency (POI), which involves ovarian function stopping before age 40 in a more abrupt way. Most people experiencing perimenopause at 38 are in a gradual transition, not a sudden shutdown. That distinction matters for how you manage it and what options are available to you.

Symptoms that may be showing up

The symptoms of early perimenopause are often subtle enough that they're easy to attribute to something else. Here's what you might notice at 38.

Cycle changes. Your period might start arriving a few days earlier or later than it used to. Bleeding might be heavier or lighter than your baseline. Spotting between periods can appear. PMS symptoms, particularly mood changes and breast tenderness in the week before your period, may intensify.

Sleep disruption. This is one of the earliest and most common signs. You might start waking in the early hours of the morning, or find it harder to fall asleep despite being tired. Progesterone, which declines early in the perimenopause transition, is a natural sedative that quiets your nervous system at night. When it drops, your sleep architecture often changes before you notice any other symptom.

Mood and anxiety shifts. New or worsening anxiety, lower mood, mood swings that feel disproportionate to the situation, or a general sense of being less resilient are common early signs. These are connected to fluctuating estrogen and progesterone, both of which influence serotonin and GABA activity in your brain.

Irregular or new vasomotor symptoms. Hot flashes and night sweats may arrive, though they're often milder and less frequent in early perimenopause than they become later. You might notice sudden warmth, flushing, or waking damp in the night without full-blown hot flashes.

Brain fog and memory changes. Forgetting words, losing your train of thought mid-sentence, or feeling mentally slower than usual can all accompany the hormone fluctuations of early perimenopause. These are temporary and not signs of lasting cognitive decline.

How to tell if it's perimenopause, stress, or something else

This is the most important question to work through carefully, because perimenopause, thyroid dysfunction, and chronic stress can all produce overlapping symptoms. Assuming one without ruling out the others leads to missed diagnoses in both directions.

Thyroid dysfunction. Hypothyroidism (underactive thyroid) is extremely common in women in their 30s and 40s and produces fatigue, weight changes, low mood, brain fog, irregular periods, and temperature sensitivity. These overlap almost perfectly with perimenopause symptoms. Before accepting a perimenopause explanation, get a full thyroid panel: TSH, free T3, and free T4. A basic TSH alone can miss subclinical hypothyroidism.

Chronic stress and cortisol disruption. Elevated cortisol from sustained stress can disrupt menstrual cycles, worsen sleep, increase anxiety, and cause irregular periods. These are real physiological effects, not a dismissal. However, stress-driven hormonal disruption and perimenopause can also coexist. The distinction matters because the management approaches differ.

Iron deficiency. Low ferritin (iron stores) causes fatigue, hair loss, brain fog, poor sleep, and mood changes. Heavy or more frequent periods deplete iron faster. Check your ferritin level specifically, not just hemoglobin, as you can be iron deficient without being fully anemic.

PCOS. If you've had irregular cycles for most of your adult life rather than just recently, polycystic ovary syndrome may be part of the picture. PCOS can also affect hormone levels in ways that resemble perimenopause.

Ask your provider to run FSH, estradiol, AMH, a full thyroid panel, ferritin, and a complete metabolic panel. This gives you a much more complete picture than FSH alone.

What to tell your doctor

The fertility conversation

This is something worth addressing directly, because it matters to a lot of people at 38 and often goes unspoken.

Perimenopause does not mean you are infertile. You can still ovulate during perimenopause, sometimes unpredictably, and conception is possible. However, declining ovarian reserve and less predictable ovulation do mean that fertility is reduced compared to your peak reproductive years.

If having children or more children is something you want, the time to have a clear conversation with a reproductive endocrinologist is now, not in a few years. An AMH level and an antral follicle count (AFC, done via ultrasound) give the most direct information about your ovarian reserve and can help you understand what your options look like.

If you are not trying to conceive, don't assume you can't. Contraception remains relevant during perimenopause, even with irregular cycles.

What early perimenopause means for your long-term health

Estrogen has protective effects on bone density and cardiovascular health. A longer perimenopause transition that begins earlier means more years with fluctuating estrogen, and eventually, more years after menopause without the same levels of estrogen. This increases the importance of building strong health habits now.

Bone health. Strength training is the most effective thing you can do for bone density. Weight-bearing exercise and resistance training both stimulate bone remodeling. Calcium (ideally through food: dairy, fortified plant milks, leafy greens) and vitamin D together support bone maintenance. If you have additional risk factors, ask your provider about a baseline DEXA scan.

Cardiovascular health. Estrogen supports healthy cholesterol levels and blood vessel flexibility. As perimenopause progresses, cardiovascular risk begins to shift. This is a good time to get a baseline lipid panel, know your blood pressure, and make sure you're getting regular aerobic exercise.

Mental health. The hormonal fluctuations of perimenopause can exacerbate existing vulnerability to depression or anxiety. If you have a history of depression, PMDD, or significant mood changes during your cycle, this transition may amplify those patterns. Talk to your provider about this proactively rather than waiting until things become severe.

Hormone therapy is an option worth discussing with a knowledgeable provider, particularly if symptoms are significantly affecting your quality of life. The evidence base for hormone therapy has become much clearer and more nuanced in recent years, and for most healthy people in their late 30s and 40s, the benefits outweigh the risks.

Experiencing perimenopause at 38 can feel disorienting, especially when you expected this chapter to be years away. But knowing what's happening is the first step toward managing it well. Your symptoms are real. Your body is not broken. This is a transition, and transitions, even early ones, can be navigated thoughtfully.

Track your symptoms over time. Ask the right questions at your next appointment. Build the habits now that protect your bone and heart health for decades ahead. You have more time and more options than you might realize.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.