There is no established causal link between abortion and uterine fibroids. Fibroids are extremely common growths that develop in the muscular wall of the uterus, and 70 to 80 percent of women will have them before age 50 regardless of their reproductive history. While one large study found a statistical association between induced abortion and fibroids, the relationship is far from clear-cut, and the major known drivers of fibroid growth are hormones, genetics, and age.
What the Research Actually Shows
The most direct study on this question looked at middle-aged and older Chinese women and found that those with a history of induced abortion had a modestly higher rate of fibroids. Women with one induced abortion had about 17 percent higher odds of fibroids compared to women with none, and women with three or more had about 36 percent higher odds, after adjusting for other factors. The overall fibroid prevalence in that study was 15.1 percent.
A few important caveats apply. This was an observational study, meaning it identified a correlation but could not prove that abortion caused fibroids. Women who have more pregnancies (and therefore more opportunities for induced abortion) also have more cumulative exposure to the hormones that fuel fibroid growth. Separating the effect of abortion itself from the effect of pregnancy-related hormonal changes is difficult. Miscarriage, notably, showed no association with fibroid risk in the same study.
Major medical reviews have not identified fibroids as a long-term health consequence of abortion. A comprehensive review by the National Academies of Sciences, Engineering, and Medicine concluded that abortion does not increase a woman’s risk of secondary infertility, pregnancy-related hypertensive disorders, preterm birth, breast cancer, or mental health disorders. Fibroids were not flagged as a recognized long-term risk.
What Actually Causes Fibroids
Fibroids grow from the smooth muscle cells of the uterine wall, and their development is driven by several well-established factors. Estrogen and progesterone are the primary fuels. Fibroid cells have more hormone receptors than normal uterine muscle cells, making them especially responsive to these hormones during the reproductive years. This is why fibroids tend to shrink after menopause, when hormone levels drop.
Genetics also play a significant role. Many fibroids contain gene mutations that differ from those in surrounding normal tissue, and fibroids tend to run in families. Other biological growth factors, including insulin-like growth factor, contribute to their development. A substance called extracellular matrix, which acts like the mortar between cells, accumulates in fibroids and gives them their firm, fibrous texture.
Beyond biology, certain demographic factors increase risk. Black women develop fibroids at two to three times the rate of white women, often at younger ages and with larger or more numerous growths. Starting your period early, having obesity, and having a diet high in red meat are also associated with higher risk. Having given birth, on the other hand, is linked to lower fibroid risk.
Why Some People Connect Abortion to Fibroids
Part of the confusion may stem from the fact that both fibroids and abortions are common, so many women experience both during their reproductive years. When fibroids are discovered after an abortion, it’s natural to wonder if one caused the other. In most cases, the fibroids were likely already developing or were too small to detect earlier.
Another source of confusion is that surgical abortion procedures like dilation and curettage (D&C) can, in rare cases, lead to scar tissue inside the uterus, a condition called Asherman’s syndrome. Scar tissue and fibroids are completely different things. Fibroids are solid growths in the muscular wall of the uterus, while adhesions are bands of scar tissue that form on the inner lining. They have different causes, different symptoms, and different treatments. Over 90 percent of Asherman’s syndrome cases occur after pregnancy-related D&C procedures, including those for miscarriage and retained placenta, not only after induced abortion.
Fibroids After Any Pregnancy Event
Pregnancy itself, whether it ends in delivery, miscarriage, or abortion, exposes the uterus to surges of estrogen and progesterone. These are the same hormones that drive fibroid growth. Any pregnancy event temporarily increases the hormonal environment that fibroids thrive in, which is why fibroids sometimes become noticeable during or shortly after a pregnancy.
This hormonal exposure happens regardless of how the pregnancy ends. It is not unique to abortion, and it does not mean the pregnancy event “caused” the fibroid. In many cases, small fibroids were already present and simply grew during the hormonal surge of pregnancy. Routine ultrasounds during pregnancy or follow-up care after any pregnancy event often reveal fibroids that would have gone unnoticed otherwise.
Putting the Risk in Perspective
Given that up to 80 percent of women develop fibroids before age 50, the baseline risk is already high for everyone. The modest statistical association found in one study does not change the clinical picture in a meaningful way. If you have had an abortion and later discover fibroids, the fibroids are far more likely explained by your age, hormonal history, and genetics than by the abortion itself. The strongest predictors of fibroid development remain the factors that were present long before any pregnancy: your family history, your hormonal profile, and time.