By Paul Muchowski, Ph.D., Founder of Defined Sleep
When I founded Defined Sleep, the first thing the data told us was that our most engaged customers were women between 40 and 65. That pattern is not coincidence. It is biology. Across nearly every life stage that distinguishes women from men hormonally — menstruation, pregnancy, perimenopause, menopause — sleep is the system that absorbs the disruption first.
I recently had the chance to discuss this on my podcast, Powered by Sleep, with Dr. Elise Grenier, M.D., a UCSF-trained, board-certified family medicine physician who runs Downtown Medical Group and The G Spa in San Francisco. She also serves on the medical advisory board for Defined Sleep. Dr. Grenier has spent more than two decades treating women across every stage of life, and she sees what the epidemiology confirms in the aggregate: among adults of reproductive age and beyond, sleep is most often disrupted not by a single dramatic event, but by a series of hormonal shifts that compound over years. The full conversation, How Menopause Affects Sleep, is available on Spotify.
I want to walk through what the conversation surfaced, because the science here matters for how we think about treatment, and because I believe the standard of care for women's sleep deserves to be much higher than it currently is.
The Prevalence Gap Is Real, but the Common Statistic Overstates It
You will sometimes hear that women are twice as likely as men to experience insomnia. That figure, while widely repeated, is not what the most rigorous epidemiology shows. A 2020 meta-analysis of 13 observational studies, published in Frontiers in Psychiatry, found that women have an odds ratio of 1.58 for insomnia compared to men: meaningfully higher, but not double. An earlier and larger meta-analysis covering more than 1.2 million participants, published in Sleep, found a risk ratio of 1.41.
The point is not to minimize the gap. The point is that the gap is real, it is consistent across populations, and it widens significantly during specific hormonal transitions. The question worth asking is not whether women sleep worse than men. The question is when, why, and what can be done about it.
Menstruation: The Quiet One-Third
Most clinical attention to sleep and the menstrual cycle has focused on cramps and discomfort. The hormonal driver, however, is more subtle. In the late luteal phase, meaning the five to seven days before menstruation begins, both estrogen and progesterone decline. Progesterone has sedative properties. Its withdrawal disrupts sleep continuity, meaning the frequency and duration of awakenings during the night.
The data here are striking. In a 2017 study using polysomnography, women with severe premenstrual syndrome reported significantly poorer subjective sleep quality during the late luteal phase. Notably, the polysomnographic measures did not always match the subjective reports. This is a consistent pattern in sleep research, and it matters: how rested a woman feels and what her sleep architecture actually looks like are not the same thing, and they require different methods to measure.
A larger epidemiological analysis of women with menstrual disturbances, published in BMC Women's Health in 2023, found that women with PMS were at least twice as likely as other women to report insomnia. Approximately half of women of reproductive age experience PMS to a degree that affects daily function. This is not a niche issue. It is one of the most common, least addressed sources of recurring sleep disruption in adult women.
Pregnancy: Sleep Quality Falls, and the Stakes Rise
When Dr. Grenier described her own experience of recognizing a pregnancy first by exhaustion, she was describing the dominant clinical signature of the first trimester: a surge in progesterone that produces overwhelming daytime fatigue and increased sleepiness. The third trimester is a different problem entirely.
By late pregnancy, sleep quality declines for the majority of women. A systematic review and meta-analysis found a 42 percent prevalence of clinically defined insomnia in the third trimester. Subjective sleep quality scores show even higher rates: in a postal survey of 650 women reported in BMC Pregnancy and Childbirth, only 29 percent rated their sleep in the past week as good, compared to 82 percent before pregnancy.
This is not merely uncomfortable. The clinical implications are significant. The largest analysis on this topic, Lu and colleagues 2021, pooled data from 120 studies and more than 58 million pregnant women. Sleep disturbances were significantly associated with preeclampsia (odds ratio 2.80), gestational hypertension (1.74), gestational diabetes mellitus (1.59), preterm birth (1.38), and stillbirth (1.25). Sleep is not a soft variable in obstetrics. It is a measurable risk factor for some of the most serious adverse outcomes a pregnancy can produce.
The Menopausal Transition: Not a Switch, a Slow Failure of Two Systems
The most useful frame Dr. Grenier offered was that menopause is a dimmer, not a light switch. Symptoms typically begin eight to ten years before the final menstrual period, with the average age of menopause around 51. During perimenopause, ovarian production of estrogen and progesterone declines progressively and erratically. Two parallel mechanisms then degrade sleep.
The first is the loss of progesterone's continuity-promoting effect. Progesterone metabolites, particularly allopregnanolone, act on GABA-A receptors and produce changes in sleep architecture similar to those seen with benzodiazepines, as documented in a 2011 placebo-controlled polysomnography study published in the Journal of Clinical Endocrinology & Metabolism. When progesterone declines, sleep continuity declines with it.
The second mechanism is vasomotor. As estrogen falls, women experience hot flashes and night sweats. A systematic review published in Climacteric reports that vasomotor symptoms occur in 50-82% of US women during the menopausal transition. The Study of Women's Health Across the Nation (SWAN), the largest longitudinal study of midlife women's health, has found that hot flashes can persist for a median of 7-10 years, and longer in some populations. Each nocturnal hot flash is, mechanically, a sleep fragmentation event.
The cumulative effect on prevalence is large. A SWAN longitudinal analysis reports that the prevalence of sleep difficulty rises from approximately 16-42% in premenopause to 35-60% in postmenopause.
A Note on Hormone Therapy, and What Recently Changed
Dr. Grenier and I discussed hormone replacement therapy at length. The clinical question for any individual woman is genuinely complex, and I will not attempt to resolve it in a blog post. What I can do is name the recent regulatory development, because it matters for the conversation.
In November 2025, the FDA initiated removal of the boxed "black box" warnings from menopausal hormone therapy products. The original warnings, applied after the 2002 results of the Women's Health Initiative trial, were associated with a sharp drop in HRT prescriptions and, in the FDA's current view, with under-treatment of women who could have benefited. Extended follow-up of the WHI cohort and contemporary evidence indicate that risks are markedly lower when therapy is initiated in women younger than 60 or within 10 years of menopause onset.
A 2022 meta-analysis published in Menopause found that combined estrogen-progesterone therapy improves objective measures of sleep quality, with transdermal delivery showing larger effects than oral. For women whose primary sleep disruption is mediated by vasomotor symptoms, this is the intervention with the strongest evidence base. It is not appropriate for everyone, and the conversation needs to happen with a clinician who understands both the data and the patient.
Where Defined Sleep Fits, and Where It Does Not
I want to be clear about what Defined Sleep is and is not. Defined Sleep is a CBD and terpene formulation that, in an FDA-registered, double-blind, placebo-controlled, randomized crossover Phase 2 clinical trial published in the Journal of Clinical Sleep Medicine, increased the percentage of time participants spent in slow-wave and REM sleep, as measured by validated wrist-worn actigraphy. The study was conducted in 125 individuals with insomnia and showed up to a 2-fold increase in restorative sleep in some participants with severe insomnia with no reported adverse events.
What Defined Sleep is not, and what no supplement should claim to be, is a treatment for hot flashes, hormonal deficiency, or the underlying biology of menopause. Vasomotor symptoms are driven by estrogen withdrawal. The most effective intervention for vasomotor symptoms remains hormone therapy, where it is appropriate. For women whose primary sleep complaint is fragmented sleep architecture and reduced restorative sleep (the kind of disruption that compounds across multiple life stages), the published clinical trial gives us evidence that a targeted CBD-terpene formulation can improve the objective measures that other approaches do not consistently address.
The point is integration. A woman in perimenopause may benefit from cognitive behavioral therapy for insomnia (CBT-I), evaluation for hormone therapy, attention to caffeine and alcohol intake (both of which independently disrupt sleep architecture), and a sleep aid that has been evaluated against placebo in a peer-reviewed trial. These are not competing solutions. They are layers of a treatment plan, and the right plan depends on which mechanism is causing the disruption.
What the Conversation Made Me Think About
The most important thing Dr. Grenier said in our discussion was simple: most women experiencing sleep disruption in their forties have been told they are stressed, that they will adjust, or that this is just how aging works. None of that is consistent with what we know. The disruption has specific, identifiable causes. There are interventions with measurable effects. The standard of care should include both.
If you are a woman experiencing sleep disruption, here are the questions worth asking yourself, your physician, or both:
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Where am I in the hormonal lifespan, and which mechanism is most likely driving my sleep disruption? Sleep disruption that began in the late luteal phase looks different from sleep disruption that began with the first hot flash. The cause matters because the treatment matters.
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Have I had a thorough evaluation, or have I been told it is stress? Thyroid dysfunction, iron deficiency, sleep apnea, and untreated mood disorders can all present as insomnia. Sleep apnea, in particular, becomes more common in postmenopausal women and is frequently missed in women of normal weight.
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What is my actual sleep architecture, and is it being measured? Subjective sleep quality and objective sleep architecture do not always agree. Wearables can give a reasonable estimate of how much time you spend in deep and REM sleep. That information is useful for matching the intervention to the disruption.
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If I am in perimenopause or menopause, have I had an honest conversation about hormone therapy? The recent FDA labeling change is an opportunity to revisit the topic with a clinician who knows the current evidence. For the right woman at the right time, the data on sleep, vasomotor symptoms, and bone health are compelling.
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What am I doing that is making the underlying biology worse? Alcohol, in particular, suppresses REM sleep at doses as low as two standard drinks. Caffeine consumed within six hours of bedtime measurably reduces slow-wave sleep. These are reversible.
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If I am using a supplement, what is the clinical evidence that it can help me? A great deal of money is spent on sleep supplements with no peer-reviewed clinical studies in humans. The evidence base for any specific product should be a starting question, not an afterthought.
The goal is not to choose between hormones, behavioral change, and supplementation. The goal is to identify what is broken and treat it accordingly, with interventions whose evidence matches the strength of the claims made for them. Women have spent too long being told their sleep is a personality trait. It is a system, and like any system, it can be understood and supported.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
FAQs
1. Why do women sleep differently than men?
Hormonal fluctuations, reproductive health, stress, and caregiving responsibilities all influence women’s sleep patterns differently.
2. How do hormones affect women’s sleep?
Hormones like estrogen and progesterone can impact sleep quality, mood, body temperature, and circadian rhythms.
3. Why is sleep often disrupted during pregnancy?
Physical discomfort, hormonal changes, frequent urination, and anxiety can all contribute to poor sleep during pregnancy.
4. Does motherhood affect long-term sleep quality?
Yes, caregiving responsibilities and interrupted sleep schedules can impact sleep quality for years.
5. How does menopause affect sleep?
Menopause can cause hot flashes, night sweats, and hormonal changes that disrupt sleep.
6. Are women more likely to experience insomnia?
Yes, research suggests women are more likely than men to experience insomnia and sleep-related issues.