Written by Anat Sapan, MD, board-certified OB-GYN · Updated November 2026
Low progesterone usually shows up first, as anxiety, poor sleep, irritability and irregular or heavy periods. Low estrogen tends to follow, with hot flashes, night sweats, brain fog, vaginal dryness and joint aches.
The short answer: Low progesterone usually shows up first, as anxiety, trouble falling asleep, heavier or shorter cycles, and worse PMS. Low estrogen tends to follow, with hot flashes, night sweats, vaginal dryness, joint aches, and brain fog. In perimenopause, most women have some of both, and the mix shifts month to month.
Women often come to me with a list of symptoms that seem unrelated. Racing heart, crying in the car, aching hands, forgetting words mid-sentence. They are usually related. They trace back to two hormones declining on different schedules.
Why progesterone falls first
Your body makes most of its progesterone after ovulation. From your late 30s, ovulation becomes less reliable. In a cycle without ovulation, progesterone barely rises. Estrogen, meanwhile, can stay normal or even spike in early perimenopause before it starts to fall. That is why the first changes often feel like PMS that never ends, rather than classic menopause. I cover this stage in detail in Perimenopause at 38.
Symptom guide: which hormone is likely involved
| Symptom | Low progesterone | Low estrogen |
|---|---|---|
| Anxiety, irritability, feeling on edge | Common, often early | Common |
| Trouble falling asleep | Common | Sometimes |
| Waking at 3 a.m., night sweats | Sometimes | Common |
| Shorter cycles, heavier periods, spotting | Common | Rare |
| Worse PMS, breast tenderness | Common (relative to estrogen) | Rare |
| Hot flashes | Rare | Common |
| Heart palpitations | Common | Common |
| Brain fog, word-finding trouble | Sometimes | Common |
| Joint and muscle aches | Rare | Common |
| Vaginal dryness, painful sex, UTIs | Rare | Common |
| Dry skin, thinning hair | Rare | Common |
| Low mood, flatness | Sometimes | Common |
This is a pattern guide, not a diagnosis. Thyroid disease, iron deficiency, and sleep apnea can mimic several of these.
Signs you are low in both
- You are in your 40s and your cycles have changed
- You have early-stage symptoms (anxiety, sleep onset trouble, heavy periods) plus later ones (hot flashes, dryness, aches)
- Symptoms vary a lot from month to month
- You feel better for a stretch, then worse again with no obvious reason
That variability is the hallmark of perimenopause. Your hormones are not steadily low. They are unstable.
Can a blood test tell you?
Partly. Because levels swing day to day in perimenopause, a single normal result does not rule anything out. This is why so many women hear "your labs are normal." The Menopause Society diagnoses perimenopause from age, cycle changes, and symptoms, not from a single hormone level.
Labs are still useful in context:
- Progesterone about seven days before your expected period can confirm whether you ovulated that cycle.
- Estradiol and FSH help most when interpreted alongside your cycle day and symptoms, or once cycles have become very irregular.
- Thyroid, ferritin, and blood sugar rule out common look-alikes.
More on this in Navigating Hormone Testing Through Perimenopause.
What treatment looks like
Treatment follows the pattern, not just the lab result.
- Progesterone-led symptoms: Micronized progesterone at bedtime often helps sleep, anxiety, and heavy cycles. It is different from synthetic progestins, as I explain in Progesterone Is Not a Progestin.
- Estrogen-led symptoms: Transdermal estradiol treats hot flashes, night sweats, aches, and brain fog. If you have a uterus, progesterone is required alongside it to protect the uterine lining.
- Both: Most perimenopausal women need both, dosed carefully and adjusted over the first two to three months.
In November 2025, the FDA announced it would remove the boxed warning from menopausal hormone therapy, reflecting decades of reanalysis of the original WHI data. I explain what that means in The FDA Just Removed the Black Box Warning. For most healthy women under 60 or within 10 years of menopause, the benefits of treating these symptoms outweigh the risks.
Frequently asked questions
What are the first signs of low progesterone?
Trouble falling asleep, new anxiety, shorter cycles, heavier periods, and spotting before your period. These often begin in the late 30s or early 40s.
What are the symptoms of low estrogen?
Hot flashes, night sweats, vaginal dryness, joint pain, brain fog, low mood, dry skin, and more frequent UTIs.
Can you have low estrogen and low progesterone at the same time?
Yes. It is common in mid to late perimenopause and after menopause.
Can low progesterone cause heart palpitations?
It can. So can low or fluctuating estrogen. I explain the mechanism in Your Heart Is Racing and Nobody Can Tell You Why. New palpitations should still be evaluated to rule out a heart rhythm problem.
Do I need a blood test to start treatment?
Not always. Symptoms and cycle history usually guide treatment in perimenopause. Labs help with dosing and ruling out other causes.
If your symptoms fit this pattern and you have been told your labs are normal, book a free 10-minute discovery call. I see patients by telemedicine in California, Florida, Illinois, and New York.
Anat Sapan MD is a board-certified OB-GYN with more than 20 years of experience, specializing in perimenopause and menopause hormone care.
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