Endometriosis makes both conceiving and carrying a pregnancy more complicated, though the majority of people with the condition do become pregnant, many without medical assistance. The disease affects fertility through several overlapping mechanisms and raises the risk of specific pregnancy complications ranging from miscarriage to preterm birth. Understanding these risks in concrete terms helps with planning, and the picture that emerges from recent research is more nuanced than the blanket reassurance or alarm that often circulates online.
How Endometriosis Interferes With Getting Pregnant
Endometriosis does not cause a single, simple fertility problem. It undermines reproduction at multiple stages, and which stage matters most varies from person to person depending on the severity and location of the disease.
At the ovarian level, endometriosis reduces what clinicians call ovarian reserve. A systematic review found that people with endometriosis had lower egg counts and diminished markers of ovarian function compared to healthy individuals, driven by chronic inflammation and oxidative stress that damages developing eggs over time.1PubMed Central. The Impact of Endometriosis on Ovarian Reserve: A Systematic Review When fertility treatment is attempted, those with advanced-stage disease tend to produce fewer mature eggs per cycle and fewer viable embryos, though the effect size is modest in milder cases.2PubMed Central. Stages of endometriosis: Does it affect oocyte quality, embryo development and fertilization rate?
Even before the egg is involved, sperm function takes a hit. The peritoneal fluid that bathes the pelvic organs in people with endometriosis contains inflammatory substances that slow sperm down. One study found that sperm exposed to this fluid penetrated roughly half as many eggs as sperm exposed to fluid from people without the condition.3PubMed. The effect of peritoneal fluid from patients with endometriosis on human sperm function in vitro A separate study reported that sperm motility dropped by about 40% after four hours and by about 80% after 24 hours of exposure to peritoneal fluid from people with moderate-to-severe disease.4PubMed. Peritoneal fluid from women with moderate or severe endometriosis inhibits sperm motility: the role of seminal fluid components
And even when fertilization succeeds, the embryo still has to implant. Research has shown that endometriosis changes the uterine lining itself, creating an environment that is less receptive to an incoming embryo. Chronic inflammation, resistance to progesterone, and disrupted immune signaling all converge to make the endometrium a harder landing pad.5PubMed Central. Endometriosis-Associated Implantation Failure: Pathophysiology, Biomarkers, and Emerging Therapeutic Strategies This is one reason why some people with endometriosis experience repeated implantation failure during IVF cycles even when the embryos appear healthy.
Improving the Odds Before Pregnancy
Surgical removal of endometriosis lesions through laparoscopic surgery is one of the most studied pre-conception interventions. A Cochrane review found that laparoscopic surgery roughly doubled the odds of an ongoing pregnancy or live birth compared to diagnostic-only surgery.6Cochrane Database of Systematic Reviews. Laparoscopic surgery for subfertility associated with endometriosis In practical terms, one study followed women after surgery and found that about 42% conceived naturally within a year, with the vast majority of those pregnancies occurring within the first six months after the procedure.7PubMed Central. Natural conception rate following laparoscopic surgery in infertile women with endometriosis
Timing matters. A retrospective study from a university endometriosis center found that about 70% of patients eventually achieved pregnancy after laparoscopic surgery, with a median time to conception of eight months. After roughly three years, no further pregnancies occurred in the cohort, suggesting a window of improved fertility that does not stay open indefinitely.8PubMed. Pregnancy after laparoscopic surgery for endometriosis: How long should we wait? The practical takeaway is that if you are trying to conceive after endometriosis surgery, the first year or so offers the best chance.
For those who move to IVF, the picture is mixed. A large study found that pregnancy rates for people with endometriosis undergoing IVF were roughly half those of people with other indications for IVF like tubal-factor infertility, with lower fertilization rates and fewer eggs retrieved per cycle.9PubMed. Effect of endometriosis on in vitro fertilization However, treating the endometriosis before starting IVF appears to help. In people with recurrent implantation failure, those who received treatment for endometriosis before or during their IVF cycles had cumulative live birth rates in the mid-40% range, compared to about 28% for those who went untreated.10PubMed Central. Analysis of IVF/ICSI Outcomes in Endometriosis Patients With Recurrent Implantation Failure: Influence on Cumulative Live Birth Rate
What Happens to Endometriosis During Pregnancy
A persistent belief holds that pregnancy “cures” endometriosis by bathing the body in progesterone and suppressing menstruation. The reality is messier. A review in Human Reproduction Update examined what actually happens to visible endometriosis lesions during pregnancy and found a wide range of outcomes. Somewhere between 15% and 50% of lesions disappeared entirely, and an additional third or so shrank. But roughly 9% to 39% of endometriomas actually grew during pregnancy, and about a quarter stayed the same size.11Human Reproduction Update. The effect of pregnancy on endometriosis—facts or fiction?
What drives this unpredictability is a process called decidualization, in which pregnancy hormones cause the tissue lining the uterus (and, in endometriosis, the misplaced tissue outside it) to transform. This transformation can cause endometriotic nodules and cysts to change in appearance on imaging, sometimes mimicking ovarian malignancy, and occasionally leading to complications like internal bleeding.12PubMed. Endometriosis in pregnancy Many people with endometriosis do experience symptom relief during pregnancy, but banking on pregnancy as a treatment strategy misunderstands the biology. Symptoms typically return after delivery once menstrual cycles resume.
Miscarriage and Ectopic Pregnancy Risk
Two of the most immediate pregnancy risks associated with endometriosis involve losing the pregnancy early. A meta-analysis published in Obstetrics & Gynecology found that endometriosis raised the risk of spontaneous miscarriage by about 40% and the risk of ectopic pregnancy by about 46%.13PubMed Central. Endometriosis and Risk of Adverse Pregnancy Outcomes A large Scottish record-linkage study found even higher figures for ectopic pregnancy specifically, with roughly 2.7 times the odds after adjusting for age and other factors.14PubMed. Pregnancy outcomes in women with endometriosis: a national record linkage study
These numbers deserve some context. A 40% increase in miscarriage risk sounds alarming, but the baseline rate of miscarriage in the general population is already substantial. Going from, say, a 15% chance of miscarriage to roughly a 21% chance is meaningful for an individual, but it still means the large majority of pregnancies in people with endometriosis do not end in early loss. The ectopic pregnancy risk is worth discussing with a care provider early on, since prompt diagnosis changes outcomes dramatically.
Preeclampsia and Blood Pressure Complications
Several meta-analyses have examined the link between endometriosis and high blood pressure during pregnancy. The findings are consistent in direction but modest in size. One meta-analysis found that endometriosis raised the odds of gestational hypertension by about 11% and preeclampsia by about 26%.15PubMed Central. The relationship between hypertensive disorders in pregnancy and endometriosis: a systematic review and meta-analysis A separate meta-analysis found similar numbers, with a pooled odds ratio for preeclampsia of about 1.19.16PubMed Central. Endometriosis and Risk of Adverse Pregnancy Outcome: A Systematic Review and Meta-Analysis
Interestingly, when researchers looked specifically at spontaneous pregnancies (excluding those conceived through IVF, which carries its own preeclampsia risk), the association was stronger. In that subgroup, endometriosis was linked to roughly 47% higher odds of preeclampsia.17PubMed. Association between Endometriosis and Risk of Preeclampsia in Women Who Conceived Spontaneously: A Systematic Review and Meta-analysis The elevated risk is not dramatic enough to warrant panic but is clinically relevant enough that regular blood pressure monitoring during prenatal care carries extra importance for people with endometriosis.
Preterm Birth
A Danish cohort study found that people with endometriosis had about 60% higher odds of delivering before 37 weeks and roughly 80% higher odds of very early delivery (before 32 weeks) compared to those without the condition.18PubMed Central. Endometriosis and preterm birth: A Danish cohort study The reasons behind early delivery differed depending on gestational age. Before 37 weeks, medically indicated preterm delivery (where a provider decides to deliver early due to complications) was more common. Before 32 weeks, spontaneous preterm labor was the main driver. This pattern suggests that the inflammatory environment of endometriosis may trigger labor contractions on its own in the earliest deliveries, while in slightly later preterm births, the issue is more often a complication like preeclampsia or placental problems that prompts the medical team to intervene.
Placental and Structural Complications
Endometriosis has been linked to several placental complications that, while less common, carry significant consequences. A large study found that people with endometriosis had nearly four times the odds of placenta previa (where the placenta covers the cervix), about double the odds of placental abruption (where it separates prematurely), and roughly three times the odds of retained placenta after delivery.19PubMed Central. Endometriosis increases the risk of obstetrical and neonatal complications Placenta accreta spectrum disorder, in which the placenta grows too deeply into the uterine wall, is also more common. A meta-analysis found that endometriosis raised the odds of this condition more than threefold.20PubMed Central. Placenta Accreta Spectrum Disorder Complicated with Endometriosis: Systematic Review and Meta-Analysis
These placental issues likely share a common thread: the abnormal implantation environment created by endometriosis. When the uterine lining is inflamed and structurally altered, the placenta may compensate by growing more aggressively or attaching in unusual locations. The practical result is a higher chance of bleeding during pregnancy, a higher rate of cesarean delivery, and the need for more careful monitoring of placental position in the second and third trimesters.
Rare but Serious Emergencies
Spontaneous hemoperitoneum in pregnancy, where blood suddenly accumulates in the abdominal cavity without trauma, is rare in the general population but disproportionately affects people with endometriosis. Case reports describe life-threatening bleeding, sometimes occurring in the second trimester, from endometriotic nodules or the fragile blood vessels surrounding them.21PubMed Central. Endometriosis-associated spontaneous major haemoperitoneum in pregnancy In a review of cases, the most common bleeding site was along the broad ligament in the pelvis.22PubMed. Spontaneous hemoperitoneum in pregnancy: A life-threatening maternal and fetal complication of endometriosis These events typically present as sudden, severe abdominal pain and require emergency surgery.
Uterine rupture is another concern, particularly for people who have had prior surgery for deep infiltrating endometriosis. Resection of deep lesions from the back of the uterus can leave a weakened area in the uterine wall, which may give way under the pressure of a growing pregnancy. A case series concluded that prior deep-infiltrating endometriosis surgery should be treated as a potential risk factor for uterine rupture.23F&S Reports. Resection of deep-infiltrating endometriosis could be a risk factor for uterine rupture: a case series with review of the literature Both of these complications are rare enough that reliable incidence figures are scarce, but awareness is important because they require emergency recognition and rapid response.24PubMed Central. Pregnancy in women with advanced endometriosis and adenomyosis: possible complications and the role of surgery
The Adenomyosis Factor
One complication in understanding endometriosis and pregnancy outcomes is that many people with endometriosis also have adenomyosis, a related condition where endometrial-like tissue grows into the muscular wall of the uterus itself. Emerging evidence suggests that some of the adverse pregnancy outcomes traditionally blamed on endometriosis may actually be driven by coexisting adenomyosis.25PubMed. Association of endometriosis and adenomyosis with pregnancy and infertility
A study comparing pregnant people who had endometriosis alone to those who also had diffuse adenomyosis found striking differences. Those with diffuse adenomyosis had significantly higher rates of babies born small for gestational age (40% versus about 11%) and showed signs of impaired blood flow through the uterine arteries throughout pregnancy. Focal, more localized adenomyosis did not carry the same risks.26PubMed. Influence of adenomyosis on pregnancy and perinatal outcomes in women with endometriosis A systematic review confirmed that having both conditions together significantly reduced pregnancy and live birth rates, though findings were inconsistent for individual complications like preterm birth or preeclampsia.27PubMed. Comorbidity of endometriosis and adenomyosis: A systematic review examining the impact of co-morbid disease on fertility and pregnancy outcomes
This distinction matters clinically. If you have endometriosis and are planning a pregnancy, knowing whether adenomyosis is also present (detectable by ultrasound or MRI) can change the risk profile substantially and influence how closely you are monitored.
Delivery and Cesarean Section Rates
People with endometriosis are more likely to deliver by cesarean section, though the reasons are tangled. Some of the increased cesarean rate comes directly from the higher frequency of placenta previa and other placental complications described above, which can make vaginal delivery unsafe. Some may reflect provider caution in the setting of prior pelvic surgery. And some is likely driven by the higher rate of IVF conception among people with endometriosis, since IVF pregnancies independently carry higher intervention rates.
Whether endometriosis raises the risk of postpartum hemorrhage is less clear. A meta-analysis found that histologically confirmed endometriosis alone was not associated with increased postpartum hemorrhage overall, though one large retrospective study did find higher rates specifically during cesarean deliveries.28PubMed Central. Association between Endometriosis and Delivery Outcomes: A Systematic Review and Meta-Analysis Given the placental abnormalities already discussed, increased vigilance during delivery remains reasonable.
Breastfeeding and Symptom Return After Delivery
Once the baby arrives, the question shifts to how quickly endometriosis symptoms come back. Breastfeeding, particularly exclusive breastfeeding, delays the return of menstrual periods and appears to extend the symptom-free window. A prospective study tracked people with endometriosis through the postpartum period and found that both the duration of exclusive breastfeeding and the length of postpartum amenorrhea were linked to reduced pain when periods did return.29PubMed Central. Effects of Breastfeeding on Endometriosis-Related Pain: A Prospective Observational Study Those who breastfed exclusively for six months or more reported the most significant and sustained reductions in menstrual pain, with benefits persisting up to two years after delivery. Longer breastfeeding was also associated with smaller ovarian endometriomas when imaging was repeated postpartum.
This does not mean breastfeeding treats the disease in any permanent way, but it extends the hormonal environment of pregnancy that tends to suppress endometriosis activity. For people weighing their feeding decisions, the potential for continued symptom relief is one additional factor to consider, alongside all the usual feeding considerations.
Offspring Health After an Endometriosis-Affected Pregnancy
A newer and still-developing area of research examines whether maternal endometriosis affects the long-term health of the child. A large Taiwanese population study found a small but statistically significant increase in developmental delay among children born to mothers with endometriosis, with an adjusted hazard ratio of about 1.11 to 1.16 depending on the statistical model used. The same study found that risks of intellectual disabilities and psychiatric disorders were not significantly different.30PubMed Central. Risk of neurodevelopmental disorders in the offspring of mothers with a history of endometriosis in Taiwanese women A separate population-based analysis found that overall neurological problems were more common in children born to mothers with endometriosis (about 27% versus 17%) and that maternal endometriosis remained an independent risk factor after adjusting for preterm birth, cesarean delivery, and other confounders.31PubMed. The impact of endometriosis on long-term neurologic morbidity of the offspring: a population-based analysis
These findings are preliminary and should be interpreted cautiously. The absolute differences are small, the studies rely on diagnostic codes rather than detailed clinical assessments, and it is difficult to separate the effect of endometriosis itself from the effects of prematurity, fertility treatments, and other mediating factors that are more common in these pregnancies. The research is worth following, but it is far too early for it to change clinical recommendations or cause undue worry.
Imaging Confusion During Pregnancy
One underappreciated challenge is that endometriosis can look different on imaging when you are pregnant. The decidualization process mentioned earlier can transform the appearance of endometriotic cysts and nodules on ultrasound or MRI, sometimes making benign endometriomas mimic ovarian cancer. Solid-appearing components may develop within previously simple-looking cysts, triggering concern and occasionally unnecessary interventions. Deep infiltrating implants can also swell and change character under the influence of pregnancy hormones.32PubMed. Endometriosis in pregnancy This is why it helps to have your imaging reviewed by someone who knows you have endometriosis and understands how pregnancy transforms these lesions. A radiologist or obstetrician who is unaware of your endometriosis history might recommend further workup for a finding that would be unremarkable in context.