The relationship between smoking and endometriosis is genuinely contradictory, and the honest answer is that it depends on what you mean by “worse.” A major meta-analysis found no clear link between smoking and developing endometriosis in the first place, yet newer large-scale studies point in the opposite direction, and the picture gets messier once you look beyond diagnosis and into pain severity, surgical recovery, and fertility. Smoking touches nearly every aspect of living with endometriosis, and in most of those areas, the effect is harmful even when the risk-of-diagnosis data seems ambiguous.
The Confusing Evidence on Whether Smoking Causes Endometriosis
For decades, researchers actually suspected smoking might protect against endometriosis. The logic was straightforward: smoking lowers circulating estrogen, and endometriosis is an estrogen-driven disease, so less estrogen should mean less disease. An older review noted that women who smoke may have a reduced risk of endometriosis, possibly because smoking alters how the body breaks down estradiol, shifting it toward inactive forms.1American Journal of Obstetrics & Gynecology. The association of smoking with estrogen-related disease: A critical review
A large meta-analysis pooling data from multiple study designs tested this idea rigorously and found no meaningful association in any direction. Whether researchers looked at current smokers, former smokers, moderate smokers, or heavy smokers, the risk of endometriosis was statistically indistinguishable from that of women who had never smoked. The results held across different types of endometriosis and different study designs.2PubMed Central. Tobacco smoking and risk of endometriosis: a systematic review and meta-analysis
But more recent research complicates that conclusion. A narrative review published in 2024 highlighted newer studies that flip the story. One study covering more than two million women found that women who both smoked and had a family history of smoking had roughly four times the risk of endometriosis compared to the general population. Another analysis of over half a million women found that heavy tobacco users had about 35% higher risk of endometriosis compared to never-users.3PubMed Central. Smoking and endometriosis: A narrative review The discrepancy between these newer findings and the earlier meta-analysis likely reflects improvements in how endometriosis is diagnosed and differences in how heavily the women studied smoked. Endometriosis can take years to be formally identified, and older studies relied heavily on surgical diagnosis, which can miss cases.
How Smoking Interacts with Hormones That Drive Endometriosis
Endometriosis grows and persists in large part because of estrogen. The misplaced tissue that characterizes the disease responds to estrogen the way normal uterine lining does, thickening and causing inflammation with each hormonal cycle. This is why many treatments aim to suppress estrogen levels.
Smoking does lower circulating estrogen by speeding up the body’s breakdown and clearance of the hormone. On the surface, that sounds like it would starve endometriosis of fuel. But the same review that described this estrogen-lowering effect also noted that smoking decreases progesterone levels.3PubMed Central. Smoking and endometriosis: A narrative review Progesterone normally counterbalances estrogen’s growth-promoting effects, so losing it can actually tilt the hormonal environment in a direction that favors endometriosis. The net hormonal effect of smoking is not simply “less estrogen equals less disease.” It is a disrupted balance between two hormones that normally keep each other in check, and that disruption can promote the survival and growth of endometrial tissue in the wrong places.
This helps explain why the “smoking protects against endometriosis” theory never held up consistently. The estrogen-lowering effect is real but incomplete. Without adequate progesterone to oppose whatever estrogen remains, the disease can still thrive.
Smoking and Pain Severity
Even if the link between smoking and getting endometriosis remains debated, the link between smoking and experiencing worse pain is more straightforward. A study examining the factors that independently predicted more severe chronic pelvic pain found that current smoking was one of them, alongside things like higher body mass index, pelvic floor tenderness, and a family history of chronic pain.4PubMed. Multifactorial contributors to the severity of chronic pelvic pain in women
This matters for anyone managing endometriosis day to day. Pain is the symptom that drives the most treatment decisions and the most quality-of-life disruption. Smoking appears to amplify pain through several routes: it impairs blood flow to pelvic tissues, it increases systemic inflammation, and it alters how the brain processes pain signals. Nicotine itself has complex effects on pain perception. In the short term, it can dull pain slightly, but chronic exposure appears to sensitize the nervous system, making pain signals louder over time. The result is that smokers with endometriosis often report more intense and more persistent pelvic pain than nonsmokers with comparable disease.
Surgical Recovery Is Harder for Smokers
Many people with endometriosis eventually undergo surgery, whether excision of endometriosis lesions, removal of ovarian cysts, or in some cases hysterectomy. Smoking is a well-known risk factor for surgical complications across specialties, and gynecologic surgery is no exception.
A study of laparoscopic hysterectomies found that smokers had roughly 50% higher odds of developing a deep surgical-site infection and about double the odds of pneumonia after surgery, even after accounting for age and other health conditions. Smokers were also about 30% more likely to be readmitted to the hospital.5Obstetrics & Gynecology. The Association Between Smoking and Postoperative Complications in Laparoscopic Hysterectomies The superficial wound complications and reoperation rates were not significantly different, so smoking does not doom every aspect of recovery, but the infection and readmission risks are real.
A separate study looking at different hysterectomy approaches confirmed the pattern: smokers had about 20% higher risk of postoperative infection when surgery was done abdominally or vaginally.6PubMed. Influence of the modifiable life-style factors body mass index and smoking on the outcome of hysterectomy These findings extend beyond hysterectomy. Any surgical procedure done for endometriosis involves cutting through tissue, repairing blood vessels, and relying on the body to heal cleanly. Smoking impairs all of those processes by constricting blood vessels and slowing the immune response at wound sites.
For someone facing endometriosis surgery, stopping smoking beforehand is one of the few modifiable factors that can meaningfully reduce complication risk. Most surgeons recommend quitting at least four to six weeks before a planned procedure, though benefits accumulate with longer cessation.
Fertility and IVF Outcomes
Endometriosis already reduces fertility, and smoking compounds this. A study of women with advanced-stage endometriosis undergoing IVF found that active smoking roughly tripled the odds of failing to achieve a live birth. The researchers concluded that smoking “dramatically decreases” the live birth rate in this group and that stopping smoking before IVF should be strongly advised.7PubMed Central. Factors associated with a poor prognosis for the IVF-ICSI live birth rate in women with rAFS stage III and IV endometriosis
The mechanisms behind this are layered. Smoking damages egg quality directly, through toxic chemicals that cause DNA damage in developing follicles. It also impairs the uterine lining’s ability to support embryo implantation, reduces blood flow to the ovaries, and alters the hormonal signals that coordinate ovulation and early pregnancy. When endometriosis is already compromising the pelvic environment, adding smoking to the mix pushes fertility outcomes from difficult to substantially worse.
This is one area where the evidence is unambiguous. Whether or not smoking affects your risk of developing endometriosis, if you already have it and are trying to conceive, smoking is one of the clearest threats to your chances of success.
Early Life Smoke Exposure and Endometriosis Risk
An unexpected thread in this research involves exposure to tobacco smoke before you ever had the choice to smoke yourself. A study of adolescents and young adults found that childhood exposure to secondhand smoke from a mother who smoked was associated with nearly three times the odds of being diagnosed with endometriosis.8PubMed Central. In utero and early life exposures in relation to endometriosis in adolescents and young adults
Interestingly, an older study of in utero exposure found the opposite: being exposed to cigarette smoke while still in the womb was associated with a lower risk of surgically diagnosed endometriosis later in life, even after accounting for the woman’s own smoking habits.9Human Reproduction. Intrauterine exposures and risk of endometriosis The authors speculated this might relate to permanent changes in the hormonal environment or blood vessel formation during fetal development.
These two findings are not necessarily contradictory, because they measure different windows of exposure. The developing fetus and the growing child are at different stages of reproductive system development, and what disrupts one stage may not disrupt the other in the same way. But the evidence here is thin and based on small numbers, so it would be premature to draw strong conclusions. What is worth noting is that the effects of tobacco on endometriosis can begin long before a person reaches the age where endometriosis symptoms typically appear. For parents, this adds one more reason to keep children’s environments smoke-free.
Polycyclic Aromatic Hydrocarbons and Environmental Chemistry
Cigarette smoke contains thousands of chemicals, and isolating which ones affect endometriosis is a challenge researchers are still working through. One area of progress involves polycyclic aromatic hydrocarbons, or PAHs, which are produced whenever organic material burns, including the tobacco in cigarettes. A study examining urinary metabolites of environmental chemicals found that seven different PAH metabolites were positively associated with the presence of endometriosis.10Scientific Reports. The effect of phytoestrogens and PAHs on endometriosis and the involvement of gut microbiota, inflammation, and molecular targets
PAHs are not unique to cigarettes. You encounter them from grilled food, vehicle exhaust, and industrial pollution. But smoking is one of the most concentrated sources of personal PAH exposure, and smokers have substantially higher levels of these metabolites in their bodies. The finding that PAHs correlate with endometriosis offers a potential mechanism that is entirely separate from the estrogen story: these chemicals may promote disease through inflammation, immune disruption, or direct effects on endometrial cells.
The same study found that a plant-derived compound called enterolactone, a phytoestrogen produced by gut bacteria when you eat certain seeds and whole grains, was negatively associated with endometriosis. This raises questions about whether diet and the gut microbiome might modulate the effect of environmental chemical exposure, but that research is still in early stages.
The Nicotinic Receptor Puzzle
One of the more surprising research threads involves nicotine’s direct effects on endometriosis cells. Since the 1980s, some researchers noted an apparent inverse relationship between smoking and endometriosis and hypothesized that nicotine itself might suppress the disease. A paper in Medical Hypotheses went so far as to suggest that nicotinic acetylcholine receptor agonists could be a novel therapy for endometriosis, and that nicotine administered without the harmful components of tobacco smoke might provide the same benefit.11Medical Hypotheses. Nicotinic acetylcholine receptor agonists may be a novel therapy for endometriosis
More recent laboratory work has found that endometriosis tissue expresses elevated levels of specific nicotinic receptor subunits compared to healthy tissue. Researchers identified several receptor subtypes that were upregulated on endometriosis cells, including confirmation that these receptors are functional, meaning they actually respond to nicotine and related molecules.12Voprosy ginekologii, akušerstva i perinatologii. Evaluation of expression patterns of different nicotinic acetylcholine receptor subunits in ovarian endometriosis in the search for promising new therapeutic targets for endometriosis
This is genuinely intriguing, but it does not mean smoking helps endometriosis. The presence of nicotinic receptors on endometriosis cells could mean nicotine suppresses them, or it could mean nicotine stimulates them, or the effect might depend on which receptor subtype is activated. The research is at the stage of characterizing what receptors are there, not yet at the stage of knowing what happens when you activate them in a clinical setting. And even if pure nicotine had some anti-endometriosis effect, cigarette smoke delivers that nicotine alongside thousands of harmful compounds that worsen pain, impair healing, damage fertility, and increase surgical complications.
What This Means If You Smoke and Have Endometriosis
The practical picture is clearer than the epidemiological one. Whether smoking slightly raises, slightly lowers, or does nothing to your baseline risk of developing endometriosis is still being argued about in research journals. But once you have the disease, smoking makes nearly every dimension of living with it harder. Your pain is likely to be more severe. If you need surgery, your infection and readmission risks go up. If you are trying to conceive, your IVF success rates drop sharply. The hormonal disruption from smoking does not neatly “starve” the disease of estrogen; it also depletes the progesterone that would otherwise keep estrogen’s effects in check.
None of this is unique to endometriosis. Smoking worsens outcomes for most chronic inflammatory conditions. But endometriosis already involves chronic inflammation, disrupted hormonal signaling, and often repeated surgical interventions, which means the added burden of smoking lands especially hard. The evidence that quitting improves surgical outcomes and fertility results is solid enough that most gynecologists and reproductive endocrinologists will raise the topic directly before planning treatment.
When Secondhand Smoke Is the Problem
A question that comes up less often but matters just as much is whether environmental tobacco exposure affects endometriosis risk in people who do not smoke themselves. As noted earlier, childhood secondhand smoke exposure from a smoking mother was associated with nearly triple the odds of endometriosis in one study.8PubMed Central. In utero and early life exposures in relation to endometriosis in adolescents and young adults This is a single study with a relatively wide confidence interval, so it would be wrong to treat the specific number as definitive. But the direction of the finding fits with what we know about how PAHs and other smoke components affect the developing reproductive system.
For people who already have endometriosis and live with a smoking partner or in environments with regular secondhand smoke, the pain and inflammation effects may apply at lower levels of exposure. Research on secondhand smoke and chronic pain in general populations supports this concern, even though endometriosis-specific data on secondhand exposure in adults is limited. Reducing environmental smoke exposure is a reasonable step alongside other symptom-management strategies, and it costs nothing.