Most women expect changes in their periods to be among the earliest signs of perimenopause. It is often the first sign they notice, but it is rarely the first sign. As I wrote in my book, The Fifth Decade: Is It Just My Life or Is It Perimenopause?, “I hope to bring awareness to women that the first sign is more typically a shift in emotions, moods and a way of engaging with the world.”
Symptoms vary greatly from woman to woman. Roughly one in five women notices no symptoms at all, while another one in five experiences severe ones. With that in mind, these are the early changes I see most often, in roughly the order they tend to appear.
A shift in emotional reactivity. Less patience, quicker irritation, tears that come more easily, a sense of being overwhelmed by demands that once felt manageable. This is typically the earliest change, and the one most easily explained away.
Premenstrual weeks that grow harder. Ovarian changes often begin in a woman’s thirties and may first appear as worsening PMS. The late thirties into the forties is when women report their most difficult premenstrual symptoms, and some women experience PMS for the first time. One telling difference: PMS lifts abruptly when a period begins, while perimenopausal symptoms may carry well into the cycle.
Distractibility and forgetfulness. Losing a train of thought, walking into a room and forgetting why, suddenly needing a calendar or checklist. These shifts are often minor enough to be blamed on a busy day or a poor night’s sleep. For some women they are frightening. I once worked with a woman whose perimenopausal forgetfulness had convinced her she had a brain tumor.
A quieter libido. Desire may become less reliable. It is easy to attribute this to frustration with a partner rather than to a changing hormonal climate.
Sleep that no longer restores. Many women are surprised to learn that during this transition the body actually needs more sleep, much as it did in adolescence, at the very time sleep is becoming lighter and more easily disrupted. The result is a growing sleep deficit, which in turn makes every other change harder to bear.
Changes in the menstrual cycle. “As long as her periods are regular, a woman may believe she is not yet in perimenopause. This is not necessarily the case.” When changes do come, cycles may shorten, lengthen, or vary by more than a week. Early in perimenopause, bleeding often becomes heavier or longer, sometimes severely so. Heavy or prolonged bleeding deserves a conversation with a gynecologist, because it can have other causes too.
The first vasomotor symptoms. Hot flashes and night sweats are what most people associate with this transition, and up to 85 percent of women experience hot flashes at some point. In the early years, though, they are often absent, or appear only as an occasional night sweat in the early morning hours. This is one reason the transition so often goes unrecognized.
Quieter physical changes. Headaches or migraines before a period, breast tenderness, bloating, fatigue, and joint aches can all belong to this early picture.
No single one of these signs confirms perimenopause, and several overlap with other conditions. Thyroid disorders in particular become dramatically more common in women in their forties and fifties, and can produce many of the same symptoms. What matters is the pattern: a cluster of changes, arriving gradually, in a woman in her late thirties or forties, that she cannot fully explain by her circumstances.
A woman does not need to experience every symptom on this list. Nor should every change in mood, memory, sleep, or physical well-being automatically be attributed to hormones. The point is to recognize that perimenopause can begin in ways that are easy to miss—and that understanding the pattern can be the first step toward finding the right explanation.
