Umbilical endometriosis on its own is unlikely to directly cause infertility, but it can be a signal that endometriosis is also present deeper in the pelvis, where it does affect fertility. About 35% of women with umbilical endometriosis have pelvic endometriosis at the same time, based on a systematic review in the Journal of Clinical Medicine. That coexisting pelvic disease is the primary fertility concern.
How Umbilical Endometriosis Connects to Fertility
Umbilical endometriosis, sometimes called a Villar’s nodule, is a small deposit of tissue similar to the uterine lining that grows in or just beneath the skin of the belly button. It’s rare, and the nodule itself sits far from the ovaries, fallopian tubes, and uterus. A surface-level nodule in the skin doesn’t physically block ovulation, interfere with egg transport, or prevent an embryo from implanting.
The real concern is what that nodule might indicate about what’s happening inside the pelvis. When surgeons have operated on umbilical endometriosis and also examined the pelvic cavity at the same time, roughly one in three patients had endometriotic lesions on pelvic organs as well. Those internal lesions, particularly on the ovaries, fallopian tubes, or the tissue lining the pelvis, are well established causes of reduced fertility. So the presence of an umbilical nodule should prompt a conversation about whether pelvic endometriosis might also be present.
The Inflammatory Factor
Endometriosis, regardless of where it’s located, triggers a body-wide inflammatory response. Ectopic endometrial tissue releases a cascade of inflammatory signals, including compounds that attract immune cells and promote swelling. These molecules don’t stay local. They circulate in the bloodstream and accumulate in the fluid surrounding the pelvic organs.
That inflammatory environment can damage eggs, sperm, and early embryos, reducing their quality and ability to survive. It also changes the lining of the uterus in ways that make it less receptive to a fertilized egg trying to implant. Even when endometriosis appears to be confined to a single spot like the belly button, there’s reason to think these systemic effects could subtly influence reproductive function. The extent of that influence in isolated umbilical cases, without pelvic disease, hasn’t been well studied.
Recognizing the Symptoms
Umbilical endometriosis has a distinctive pattern that sets it apart from other belly button problems. The hallmark is cyclical symptoms tied to your period: a firm, tender nodule at the navel that swells, becomes painful, and sometimes bleeds right around menstruation. The bleeding typically starts within the first couple days of your period and resolves by the time it ends. The nodule often has a bluish-purple color.
These cyclical features are what separate it from other conditions that can cause an umbilical lump, including hernias, granulomas, or a type of metastatic cancer deposit called a Sister Mary Joseph nodule. If your belly button lump doesn’t follow your menstrual cycle, other diagnoses need to be ruled out. Diagnosis is usually confirmed through tissue biopsy after the nodule is removed, which also excludes anything more serious.
How It’s Diagnosed and Assessed
Doctors can often suspect umbilical endometriosis based on the pattern of symptoms alone, but imaging helps confirm it and check for pelvic involvement. Ultrasound typically shows a dark (hypoechoic) mass with visible blood flow at the navel. MRI provides more detail, showing a nodule that appears dark on most imaging sequences, sometimes with small bright spots indicating old blood products.
The more important part of the workup, from a fertility perspective, is evaluating the pelvis. MRI can detect endometriomas (blood-filled cysts on the ovaries) that appear characteristically bright on certain sequences. Given that about a third of women with umbilical endometriosis have concurrent pelvic disease, imaging the pelvis is a reasonable step, especially if you’re concerned about fertility or experiencing symptoms like painful periods, pain during sex, or difficulty conceiving.
What Surgery Can Do for Fertility
Surgical removal is the preferred treatment for umbilical endometriosis. The nodule is excised, symptoms resolve, and the tissue is examined to confirm the diagnosis. European guidelines recommend that this be done at a center with experience in endometriosis care, ideally with a multidisciplinary team.
If pelvic endometriosis is found at the same time, surgical removal of those internal lesions can meaningfully improve the chances of pregnancy. In women with moderate to severe pelvic endometriosis, the spontaneous pregnancy rate before surgery sits between 2% and 10%. After surgical excision, that rate rises substantially. One meta-analysis found the spontaneous pregnancy rate jumped from 4% to 43% after surgery in women with advanced disease. Across a large review of over 1,500 women with deep endometriosis who had surgery, about 53% achieved pregnancy afterward. Of those who conceived, roughly 43% did so without assisted reproduction, while the rest used fertility treatments like IVF.
Importantly, hormone-suppressing medications prescribed after surgery don’t improve future pregnancy rates. Guidelines specifically advise against using postoperative hormonal suppression if the goal is to conceive. If you’re trying to get pregnant after endometriosis surgery, the typical approach is to start trying relatively soon rather than spending months on hormonal treatment first.
When Fertility Isn’t Affected
Not every woman with umbilical endometriosis will have fertility problems. Some have the condition for years and conceive without difficulty. In case reports, women with confirmed Villar’s nodules and even coexisting pelvic endometriosis have had no history of subfertility. The American Society of Reproductive Medicine considers moderate to severe endometriosis to be associated with infertility, but milder forms don’t always have a measurable effect on the ability to conceive.
The key variable is what’s happening inside the pelvis. If your umbilical endometriosis exists in isolation, or alongside only minimal pelvic disease, your fertility may be entirely unaffected. If there’s significant pelvic involvement, particularly endometriomas on the ovaries or deep lesions near the fallopian tubes, the picture changes. That’s why the diagnostic workup matters more than the belly button nodule itself when it comes to understanding your fertility outlook.