What Are the Chances of Getting Pregnant With One Ovary?

Losing an ovary does not mean losing your fertility. Research consistently shows that women with one ovary can and do get pregnant, often at rates comparable to women with two. In one retrospective comparison, about 49% of women who had undergone ovary removal went on to have at least one successful pregnancy, a figure statistically indistinguishable from women who had other abdominal surgeries with both ovaries intact. The picture gets more nuanced when you factor in age, the reason the ovary was removed, and whether you’re trying naturally or through fertility treatment, but the headline finding is reassuring.

How the Remaining Ovary Picks Up the Slack

Your body has a remarkable ability to compensate after losing an ovary. Normally, the two ovaries take loose turns releasing an egg each month, but when one is removed, the remaining ovary doesn’t simply work at half capacity. It ramps up. Animal research has demonstrated that normal ovarian function, including follicle selection, ovulation, and the hormonal support needed to sustain a pregnancy, can be maintained with as little as 5% of the original ovarian tissue remaining.¹ In humans, this compensation isn’t quite as dramatic, but the remaining ovary does tend to ovulate more frequently than a single ovary in a two-ovary system would.

The hormonal side reflects this adjustment. After one ovary is removed, follicle-stimulating hormone (FSH) levels tend to rise, signaling the pituitary gland to push the remaining ovary harder.² That elevated FSH helps recruit follicles from the single ovary so that regular monthly cycles usually continue. The trade-off is that markers of ovarian reserve shift: anti-Müllerian hormone (AMH), which reflects the pool of remaining eggs, drops to roughly half, and baseline FSH runs higher than in women with both ovaries.³ Those lab values can look alarming on paper, but they don’t translate neatly into an inability to conceive.

Natural Conception Rates

The most direct evidence on spontaneous pregnancy comes from studies tracking women who tried to conceive after losing an ovary. A study of cancer survivors who had one ovary cryopreserved (and thus were living with only the remaining one) found that among 57 women actively trying to get pregnant, 41 succeeded, producing a total of 68 pregnancies. Strikingly, 93% of those pregnancies happened through natural conception rather than fertility treatment.⁴ That’s a roughly 72% natural pregnancy rate among those who tried, though this population was generally younger and motivated, so the number isn’t universal.

A separate retrospective comparison put the pregnancy rate for women after ovary removal at about 48.5%, compared with 41% for women who had undergone appendectomy and nearly 54% for those who had a gallbladder removal. None of those differences were statistically meaningful, and miscarriage rates were similar across all three groups.⁵ The takeaway is that when you compare women who lost one ovary to women who had comparable surgeries but kept both, the pregnancy success stories look similar.

What Happens With IVF and Fertility Treatment

If you’re pursuing in vitro fertilization with one ovary, the process works a bit differently than for someone with two ovaries, but the end result is often the same. The main difference is in the stimulation phase. One large study found that women with a single ovary needed more fertility medication, had a longer stimulation period, and produced fewer eggs (about seven compared with nine) and fewer embryos (about four versus five). Despite all that, the fertilization rate and the pregnancy rate per retrieval cycle were virtually identical: roughly 26% for one-ovary patients versus 27% for two-ovary patients.⁶

Another IVF study actually found a higher pregnancy rate among one-ovary patients (about 53%) compared to two-ovary patients (about 21%), though the researchers attributed some of that surprising result to the small sample size and the specific characteristics of the patients in their program.⁷ While you shouldn’t take that single result as proof that losing an ovary somehow helps, it does reinforce the broader pattern: having one ovary doesn’t doom an IVF cycle.

The elevated FSH levels that come with having one ovary can, in some cases, account for a weaker stimulation response.⁸ Fertility clinics typically account for this by adjusting medication protocols upward. You may go through more medication and a slightly longer stimulation cycle, but the final pregnancy rates converge with those of two-ovary patients across multiple studies. If anything, the consistent finding across the research is that the number of ovaries matters less than the quality of the eggs the remaining one produces.

Age Matters More Than Ovary Count

Age at the time of surgery turns out to be one of the strongest predictors of whether having one ovary will affect your chances. A large Swedish population study found that the reduced likelihood of having children after ovary removal was primarily seen in women who had the surgery at an older age. Among younger women who lost an ovary, the effect on childbearing was smaller or absent. The interaction between age and outcomes was statistically significant, meaning it wasn’t a fluke pattern in the data.⁹

This makes biological sense. A younger woman’s remaining ovary has a larger reserve of eggs to draw from, giving the compensatory mechanism more to work with. An older woman’s remaining ovary is already depleted by the natural decline that begins well before menopause, and cutting the total pool in half can push her closer to the threshold where conception becomes difficult. If you lost an ovary in your twenties and want children in your early thirties, the odds are solidly in your favor. If the surgery happened at 38 and you’re hoping to conceive at 42, the math is tighter, and fertility treatment may play a more important role.

A Shorter Fertile Window

Even though pregnancy rates remain encouraging, having one ovary does compress your reproductive lifespan. Menopause arrives earlier, and the effect is consistent across multiple large studies. One community-based cohort study found that women who had undergone ovary removal reached menopause about a year earlier than women who kept both ovaries (mean age 49.6 versus 50.7 years) and that the risk of premature ovarian insufficiency, meaning menopause before age 40, was nearly four times higher.¹⁰ A separate study pegged the difference at about 1.8 years earlier, finding that the effect was comparable in size to the menopause-advancing effect of smoking.¹¹

Interestingly, a Norwegian population study noted that the actual shift in menopause timing was “weaker than anticipated from the loss of ovarian follicular reserve,” suggesting that compensatory mechanisms in the remaining ovary do cushion the blow to some degree.¹² Losing half your eggs doesn’t mean losing half your fertile years. Still, the practical implication is real: if you have one ovary and plan to delay pregnancy, the margin of safety is narrower than it would be with two. The years between 35 and menopause deserve more deliberate planning.

The earlier menopause effect is most pronounced when the ovary is removed in early adulthood. The longitudinal cohort study found that ovary removal around age 30 more than doubled the risk of earlier menopause compared with removal near menopause age, and the elevated risk was fairly uniform across women who lost an ovary between ages 20 and 40.¹⁰ This doesn’t mean those women can’t get pregnant; many do. But it underscores that the clock ticks a bit faster with one ovary, and awareness of that can inform the timing of family planning.

Why the Ovary Was Removed Can Affect Your Outlook

Not all single-ovary situations are created equal. The reason you lost the ovary shapes both the health of the remaining one and how easy it will be to conceive afterward.

Ovarian torsion, where the ovary twists on its blood supply and has to be surgically removed, is one of the more common reasons young women end up with a single ovary. A study following women who had this happen found that about 79% of them later sought treatment for infertility. Of those treated, roughly 46% conceived, some through IVF and some through less intensive approaches like ovulation induction with insemination. Three of the women in the study had pelvic adhesions discovered during follow-up, which can complicate fertility by affecting the fallopian tube’s ability to capture an egg.¹³

Endometriosis is another common culprit. When an ovary is removed because of an endometrioma (a cyst caused by endometriosis), the underlying disease often affects the remaining ovary and surrounding tissue too. Roughly half of women experiencing infertility have some degree of endometriosis, and the disease can impair ovarian function independent of how many ovaries remain.¹⁴ For these women, treating the endometriosis itself is often just as important as compensating for the missing ovary.

When the reason for surgery was benign and limited to one ovary, like a dermoid cyst or a borderline tumor, the remaining ovary is generally healthy and unaffected. These are the cases where the research on pregnancy rates is most encouraging, because the studies showing comparable pregnancy outcomes were largely conducted in women who lost an ovary for benign reasons.⁵

Adhesions and the Remaining Fallopian Tube

One underappreciated factor is what surgery does to the anatomy around the remaining ovary. Any abdominal or pelvic surgery can cause adhesions, bands of scar tissue that form between organs during healing. If adhesions develop around your remaining fallopian tube or ovary, they can physically block the path an egg needs to travel. Even if ovulation is happening normally, a blocked or kinked tube means the egg and sperm can’t meet.

This is one reason fertility specialists sometimes recommend a laparoscopy after ovary removal if you’re struggling to conceive. In the torsion study mentioned earlier, three out of the women evaluated had pelvic adhesions found on follow-up laparoscopy.¹³ Adhesion-related infertility can sometimes be surgically corrected, or bypassed entirely with IVF, since IVF retrieves eggs directly from the ovary with a needle and doesn’t require a functional tube.

It’s also worth noting that some women with one ovary still have both fallopian tubes. The tube on the side of the removed ovary doesn’t disappear, and there’s limited evidence that it can sometimes capture an egg released from the opposite ovary (a phenomenon called transperitoneal migration). This isn’t something to count on, but it does happen and may contribute to the surprisingly robust pregnancy rates seen in one-ovary women.

Conditions That Coexist With a Single Ovary

Some women living with one ovary also have polycystic ovary syndrome (PCOS) or polycystic morphology in the remaining ovary. Research comparing women who have polycystic features on only one ovary to women with classic PCOS found that the unilateral form tends to be milder, with fewer hormonal disruptions and less hyperandrogenism.¹⁵ If your remaining ovary happens to have polycystic features, your fertility picture depends more on how the PCOS is managed than on having lost the other ovary. Ovulation induction medications like letrozole or clomiphene are typically effective in this group.

For women who lost an ovary during cancer treatment, the picture is more complex. Chemotherapy or radiation may have affected the remaining ovary before or after the surgery. The encouraging data from the cryopreservation study, where 93% of pregnancies were natural, came from women whose remaining ovary had weathered cancer treatment and still functioned well enough to conceive.⁴ But outcomes vary widely depending on the type of chemotherapy, radiation field, and how long the treatment lasted. A fertility specialist can help assess the remaining ovary’s reserve with blood tests and ultrasound after treatment ends.

Fertility Preservation Before or During Surgery

If you know in advance that an ovary needs to be removed, there are preservation options worth discussing with your surgeon. Egg freezing (oocyte cryopreservation) is the most established option: before the surgery, the ovary that will be removed can be stimulated to produce multiple eggs, which are then retrieved and frozen. This gives you a backup supply independent of what the remaining ovary does over time.

Ovarian tissue cryopreservation is a newer technique in which a portion of the ovarian cortex is surgically removed and frozen. Later, it can be transplanted back into the body to restore hormonal function and potentially fertility. A systematic review identified hundreds of cases in which ovarian tissue had been successfully removed and later transplanted, though the technique remains more common in cancer patients than in women losing an ovary for benign reasons.¹⁶ The practical value of this approach depends on your age, diagnosis, and how urgently the surgery is needed. It’s not available everywhere, but it’s increasingly offered at specialized fertility centers.

Even without formal preservation, simply knowing that you’ll be living with one ovary allows for proactive planning. Getting baseline AMH and FSH levels checked after surgery gives you a starting point for monitoring your ovarian reserve over time. If the numbers suggest a rapidly declining reserve, you can move the timeline for conception up or freeze eggs while the remaining ovary is still producing well.

When One Ovary Is Something You Were Born With

Not everyone with a single ovary lost one surgically. Some women are born with only one functioning ovary, a condition that may not be discovered until an ultrasound for some other reason or a fertility workup. In these cases, the remaining ovary has been compensating since puberty, and the hormonal system has never known anything different. Menstrual cycles are typically regular, and many of these women conceive without ever knowing they had only one ovary.

The fertility research on surgical removal of an ovary may actually be more pessimistic than what applies to women born with one, because surgery carries its own risks (adhesions, inflammation, and disruption to the blood supply of nearby structures) that a congenital single ovary avoids. If your single ovary is congenital and functioning normally, there’s no particular reason to assume your fertility is compromised, though the shorter reproductive window associated with a smaller total egg pool still applies. Tracking your ovarian reserve with periodic lab work is sensible, especially as you move through your thirties.

1
Biology of Reproduction. Effects of Ovarian Tissue Reduction on the Menstrual Cycle: Persistent Normalcy after Near-Total Oophorectomy
2
Journal of Animal Science. Effect of Unilateral Ovariectomy at Three Stages of the Estrous Cycle on the Activity of the Remaining Ovary and Pituitary Gland
3
PubMed Central. Two is not always greater than one: patients with one ovary have similar assisted reproductive technology (ART) outcomes compared to patients with two ovaries
4
Reproductive BioMedicine Online / PubMed Central. Fertility in cancer patients after cryopreservation of one ovary
5
PubMed Central. Biological Impact of Unilateral Oophorectomy: Does the Number of Ovaries Really Matter? – Section: Unilateral oophorectomy and spontaneous fertility
6
Human Reproduction. Women with one ovary have decreased response to GnRHa/HMG ovulation protocol in IVF but the same pregnancy rate as women with two ovaries
7
PubMed. Treatment outcome in women with a single ovary versus patients with two ovaries undergoing in vitro fertilization and embryo transfer (IVF/ET)
8
PubMed. Significance of basal follicle-stimulating hormone levels in women with one ovary in a program of in vitro fertilization
9
Human Reproduction Open. Likelihood of childbirth in women with one versus two ovaries: a Swedish population-based study of women treated with unilateral oophorectomy for benign indications
10
PubMed Central. Unilateral Oophorectomy and Age at Natural Menopause: A Longitudinal Community‐Based Cohort Study
11
PubMed. The influence of unilateral oophorectomy on the age of menopause
12
Human Reproduction. Is unilateral oophorectomy associated with age at menopause? A population study (the HUNT2 Survey)
13
PubMed Central. Fertility after oophorectomy due to torsion
14
PubMed Central. Achieving Successful Pregnancy in a Patient With Ovarian Endometriosis Through Assisted Reproductive Technology (ART) Intervention: A Case Report
15
PubMed. Characterization of unilateral polycystic ovary compared with polycystic ovary syndrome
16
Thieme E-Journals / PubMed Central. Surgical Aspects of Ovarian Tissue Removal and Ovarian Tissue Transplantation for Fertility Preservation