Surgical Menopause: What Changes When Ovaries Are Removed
Surgical menopause happens when both ovaries are removed before natural menopause, so ovarian estrogen stops at once instead of tapering. Long-term studies link it to higher mortality and dementia risk, with the clearest signals in women operated on young who didn't take estrogen. The main menopause guideline recommends estrogen afterward unless there's a reason you can't take it.
Many women going into a hysterectomy are asked, often briefly, whether to "take the ovaries too." It can sound like tidying up while the surgeon is already there. The long-term research suggests it's one of the more consequential decisions in the whole operation — and that what happens afterward, especially with estrogen, changes the picture considerably.
What is surgical menopause, exactly?
It's menopause caused by removing both ovaries — a bilateral oophorectomy — before your periods would have stopped on their own. In natural menopause, ovarian hormones fall unevenly over several years. With surgery, ovarian estrogen production ends on the day of the operation, which is why symptoms can arrive suddenly and intensely.
Two things are often confused here. A hysterectomy removes the uterus; on its own, it ends periods but doesn't remove the ovaries. Removing the ovaries is a separate decision, sometimes made for cancer risk (for example in women with BRCA gene variants), and sometimes simply offered alongside a hysterectomy for a benign condition. Only the second — removal of both ovaries — causes surgical menopause.
Does a hysterectomy alone bring on menopause?
Not right away, but the evidence suggests it can bring it forward. One prospective study tracked hormone levels for five years in women who'd had a hysterectomy and compared them with similar women who hadn't, and the hysterectomy group reached menopause noticeably sooner on average.
In this study, menopause was defined by a single blood test showing FSH of at least 40 IU/L, not by symptoms or a year without periods — which isn't possible to track once the uterus is gone. It's a reasonable proxy, but worth knowing that "menopause" here is a lab threshold.
What does removing the ovaries mean for long-term health?
The clearest long-term data comes from the Nurses' Health Study, which followed tens of thousands of women who had a hysterectomy for benign disease, over up to 28 years, and compared those who kept their ovaries with those who had both removed. Removal was never linked to better overall survival at any age.
The most telling detail is where the signal was clearest. Overall, results didn't differ significantly by age at surgery. But for women younger than 50 at the time of surgery, removing the ovaries was linked to significantly higher mortality in women who had never used estrogen therapy (HR 1.41) — and not in past or current users. Assuming 35 years of life after surgery, the authors estimated that for every 8 women under 50 who had their ovaries removed and never took estrogen, one additional death from any cause would occur.
This is observational data, and that matters. Women who chose to keep or remove their ovaries, or to take estrogen, may differ in ways the researchers couldn't fully adjust for. The study shows a strong, consistent association — not a controlled experiment. It's still one of the largest long-term studies on the question — and the North American Menopause Society now states that "ovarian conservation is recommended when hysterectomy is performed for benign indications in premenopausal women at average risk for ovarian cancer."
What about memory and the brain?
A long-running Mayo Clinic cohort study suggests there's a link, and that age at surgery matters. Women who had their ovaries removed before menopause were more likely to develop cognitive impairment or dementia later in life than women of the same age from the same community who hadn't.
Note what this study included: removal of one ovary as well as both, so it isn't only about full surgical menopause. The authors found similar associations for unilateral and bilateral surgery considered separately, and regardless of the (non-cancer) reason for surgery. They interpreted the age gradient as suggesting "a critical age window for neuroprotection." If brain fog is on your mind right now, our article on menopause brain fog explains why the everyday version is a different and much more reassuring story.
Does estrogen therapy help after surgical menopause?
According to the North American Menopause Society, yes — and for women who have both ovaries removed before the usual age of menopause, it's the default recommendation rather than an optional extra, unless there's a specific medical reason in your own history against it.
The same statement notes younger women may need higher doses to relieve symptoms and protect bone, and that short-term hormone therapy appears safe in women with BRCA1 or BRCA2 variants who have risk-reducing ovary removal before the average age of menopause. If your uterus was removed too, estrogen alone is usually used; if it wasn't, a progestogen is added to protect the uterine lining. For the wider hormone therapy picture, see our HRT guide.
What should you ask before surgery?
If you're facing a hysterectomy or ovarian surgery, the research above suggests a few direct questions worth bringing to your surgeon before the day, written down, rather than relying on a quick consent conversation in a pre-operative room when you're already anxious and short on time.
- Is removing my ovaries medically necessary, or is it being offered as optional alongside the hysterectomy?
- If it's for cancer risk, what is my actual risk with and without removal, given my family history and genetic testing?
- If both ovaries are removed, will I be offered estrogen therapy afterward, and is there any reason I shouldn't take it?
- If I keep my ovaries, could the hysterectomy still bring menopause earlier, and what should I watch for?
Where to go from here
If your menopause came early without surgery, our early menopause guide covers that situation specifically, including the heart-risk research. For the bone side of estrogen loss, our osteoporosis article goes deeper. And if hot flashes after surgery are disrupting your sleep, our guide to HRT and insomnia is a good next step.
For how all of this fits into the bigger picture of midlife sleep, start at the complete perimenopause and menopause sleep guide.
Key takeaways
- Surgical menopause means both ovaries were removed before natural menopause; a hysterectomy alone (ovaries kept) is not surgical menopause.
- A hysterectomy may still bring menopause sooner: in one study, women with low starting FSH reached menopause 3.7 years earlier than comparable women without surgery.
- Removing the ovaries never improved overall survival in the Nurses' Health Study; all-cause mortality was higher (HR 1.13), with the clearest signal in women under 50 who never used estrogen (HR 1.41).
- Oophorectomy before menopause was linked to a 46% higher risk of cognitive impairment or dementia in a Mayo Clinic cohort, rising the younger the age at surgery.
- Estrogen is the default afterward: the North American Menopause Society says it is indicated after removal of both ovaries before the average age of menopause, unless contraindicated.
- Ask before surgery, not after: whether ovary removal is necessary, and what your hormone plan will be if it happens.
Frequently asked questions
What is surgical menopause?
Surgical menopause is menopause caused by removing both ovaries (bilateral oophorectomy) before natural menopause. Instead of ovarian hormones tapering over several years, ovarian production of estrogen stops at the time of surgery.
Does a hysterectomy cause menopause if the ovaries are kept?
Not immediately, but it may bring menopause earlier. In a prospective study of 257 women having a hysterectomy, those with low starting FSH levels reached menopause 3.7 years earlier than comparable women who had no surgery, and removing one ovary along with the uterus brought it about 4.4 years earlier still.
Does removing the ovaries affect long-term health?
In the Nurses' Health Study, women who had both ovaries removed at hysterectomy had higher all-cause mortality over 28 years than women whose ovaries were kept (hazard ratio 1.13). The clearest signal was in women who had surgery before 50 and never used estrogen therapy (hazard ratio 1.41), and at no age was removing the ovaries linked to longer survival.
Is oophorectomy linked to memory problems or dementia?
A Mayo Clinic cohort study found women who had one or both ovaries removed before menopause had a 46% higher risk of later cognitive impairment or dementia than women who did not, and the risk was higher the younger they were at surgery. It is an observational finding, not proof of cause.
Should I take estrogen after surgical menopause?
The North American Menopause Society states that, unless contraindicated, estrogen therapy is indicated for women who have both ovaries removed before the average age of menopause, to treat hot flashes, improve bone density and reduce osteoporosis risk. Women who still have a uterus also need a progestogen for endometrial protection.
Sources cited
- Parker WH, Feskanich D, Broder MS, Chang E, Shoupe D, Farquhar CM, Berek JS, Manson JE. Long-term mortality associated with oophorectomy compared with ovarian conservation in the Nurses' Health Study. Obstet Gynecol. 2013;121(4):709-716.
- Rocca WA, Bower JH, Maraganore DM, Ahlskog JE, Grossardt BR, de Andrade M, Melton LJ. Increased risk of cognitive impairment or dementia in women who underwent oophorectomy before menopause. Neurology. 2007;69(11):1074-1083.
- Farquhar CM, Sadler L, Harvey SA, Stewart AW. The association of hysterectomy and menopause: a prospective cohort study. BJOG. 2005;112(7):956-962.
- The 2022 Hormone Therapy Position Statement of The North American Menopause Society. Menopause. 2022;29(7):767-794.
How this article was checked
The North American Menopause Society statement was read in its full published text; the estrogen recommendation after oophorectomy is quoted as written there. The mortality, dementia and hysterectomy figures come directly from the Parker, Rocca and Farquhar abstracts, including the details that change their meaning — that the clearest mortality signal sat in one subgroup (women under 50 who never used estrogen) while results overall did not differ significantly by age at surgery, that the dementia study included removal of a single ovary, and that "menopause" in the hysterectomy study was defined by a blood test. An independent fact-check caught one real error in an earlier draft: it said the extra mortality was "concentrated" in women under 50 who never used estrogen. The study's full text says results overall did not differ significantly by age at surgery; that group is simply where the signal was clearest (HR 1.41). The wording above has been corrected everywhere it appeared.
It has not been reviewed by a clinician. Ellen Hayes is a researcher and writer, not a doctor, and nothing here is a diagnosis or a substitute for being seen by one.
Ellen Hayes
Health & Wellness Writer and Researcher
Hi — I'm Ellen. "Do you want us to take the ovaries too?" is a question that can get a few seconds in a pre-op conversation. Reading the long-term research, I kept thinking it deserves a lot more than that — so this is the list of questions I'd want in my own hand beforehand.
I'm not a doctor. I'm not an expert — and I'm never going to talk down to you like one. I'm a woman in the middle of perimenopause who got tired of vague answers, started reading the actual research, and writes it down here in plain English, the way I'd explain it to a friend over coffee. More about Ellen →