In July 2022, Sage Collins, now 35, had bowel issues at a friend’s wedding, ducking into the bathroom all night long. When she found out she was pregnant the next month, she attributed her GI troubles to fluctuating hormones. By the fall, blood was streaking her stool, so she made a doctor’s appointment. Her bloodwork came back normal, with the exception of anemia — common in pregnancy.
As Collins’s pregnancy progressed, so did her rectal bleeding, at one point sending her to the hospital, where she was given iron infusions. During labor, the blood loss from her rectum was enough to set off alarm bells. A nurse told Collins a gastroenterologist would visit her before she left the hospital, but no one stopped by. The bleeding persisted postpartum, and weight fell off her.
“It got so bad that I remember lying in [my son] Asher’s playroom with him when he was 6 or 7 months old, and I was so uncomfortable because I had to keep running to the bathroom,” she said. “I was like, ‘This is no way for me to parent or go through life.’”
Collins made an appointment with her primary care physician who ordered the colonoscopy that would lead to a diagnosis of Stage 4 rectal cancer, in March 2024, nearly two years after she first experienced symptoms. The mass was the size of a golf ball, and the cancer had spread to her liver.
Data from Australia suggests cases of pregnancy-associated colorectal cancer (which arise during pregnancy or in the first year postpartum) have increased by about 6 percent each year from 1994 to 2013. There’s no evidence that pregnancy itself increases susceptibility, said Marwan Fakih, division chief of GI medical oncology at cancer center City of Hope. And that’s still a very small number of cases total — it affects about 1 in 13,000 pregnancies, Fakih said.
But the increasing overlap of pregnancy and colorectal cancer poses unique risks because of how it can delay diagnosis and complicate care.
Experts say the rise in cases of pregnancy-associated CRC largely reflects a broader trend: an uptick in younger people. A 2026 report from the American Cancer Society shows that while rates of colorectal cancer have dropped in people over age 65 in the past decade, incidence in young people has steadily climbed, rising by 3 percent annually for those ages 20 to 49. In the 20-to-39 group, rates have doubled in the past 35 years.
Meanwhile, the average age of first pregnancy has also gone up during this time, with women over 30 accounting for over half of births in 2023, compared to just 30 percent in 1990. As pregnancy shifts later and CRC moves earlier, “there’s been a crossover between the two,” said Nancy You, director of the Young On-set Colorectal Cancer Program at University of Texas MD Anderson.
How pregnancy-associated colorectal cancer can evade diagnosis
Of all people diagnosed with CRC under 50 — including those who are pregnant or postpartum — 75 percent will get diagnosed at either Stage 3 (when cancer has spread to the lymph nodes) or Stage 4 (when it’s metastasized to a nearby organ), which are harder cancers to cure. Data on the stage of diagnosis for pregnancy-associated CRC, in particular, is limited but suggests a similar proportion of late-stage diagnoses, with nearly half at Stage 4.
CRC symptoms can be easy to miss in pregnancy because many mirror those of pregnancy itself or issues that frequently appear during it.
For starters, bowel changes happen in pregnancy for a variety of reasons, including stress, shifts in eating habits and the fact that the growing fetus can get in the way of the bowels moving, You said.
Resulting constipation and straining to pass stool, along with the weight of the fetus on the pelvic floor, ups the risk of hemorrhoids, said Kimmie Ng, founding director of the Young-Onset Colorectal Cancer Center at Dana-Farber Cancer Institute.
Anemia is also common during pregnancy because of the elevated demand for red blood cells to supply the placenta. And abdominal discomfort, nausea, vomiting and fatigue are all CRC symptoms that are easily attributable to pregnancy too, Ng said.
Even postpartum, symptoms may be ascribed to the fallout of pregnancy and childbirth.
Marisa Peters was 33 with an 18-month-old son when she started to have intermittent bowel changes, low energy and ribbons of blood in her stool. When she told her doctor, he essentially said, “Your body is not going to be the same after you’ve had a baby, and you probably have hemorrhoids,” Peters said. It was the same refrain for nearly six years, including two more pregnancies, until the symptoms began to affect her daily life.
“I was grabbing my youngest’s diapers in the car and shoving them down my pants for fear that I wouldn’t make it to a bathroom,” Peters said. Suspecting a gut health issue, her doctor referred her to a gastroenterologist, who would ultimately diagnose her with Stage 3 rectal cancer.
The challenges of treating colorectal cancer during and after pregnancy
Treating CRC during pregnancy involves balancing what’s best for the mother and fetus, which requires multiple providers including the OB/GYN, gastroenterologist, surgeon and medical oncologist, You said.
The best route depends on the stage of the cancer and the pregnancy trimester. Early-stage colorectal cancers can often be fully cured with surgery, Fakih said. It’s also the only viable intervention in the first trimester (when other treatments threaten the formation of the fetus), though risk is considered lowest in the second trimester, when the fetus is mostly developed. Operating late in pregnancy could up the chance of preterm labor.
For more advanced disease, treatment decisions get trickier and differ between colon and rectal cancer. Treating late-stage colon cancer generally requires chemotherapy; surgery is often not possible or successful with disease that’s spread to other organs, Fakih said.
For rectal cancers beyond Stage 1 — which account for most pregnancy-associated CRC cases and have a high risk of local recurrence — the typical recommendation involves chemotherapy and radiation before surgery. Preoperative treatment helps kill tumor cells and sterilize nearby blood vessels to limit the risk of regrowth postsurgery, You explained.
The problem is, chemotherapy is only recommended during the second or third trimester, and pelvic radiation is dangerous throughout pregnancy, Fakih said. So that can leave women diagnosed with late-stage CRC in the first trimester with the often emotionally and sometimes legally complicated (depending on where they live) decision of either ending the pregnancy to begin treatment, or delaying care and jeopardizing their health.
Later in pregnancy, it’s possible to shift the sequence of care, Ng said, for instance starting with chemo, and then continuing postpartum with radiation and surgery. In some cases, women might also deliver early to more quickly begin treatment, You said.
Treatment postpartum can also take a different trajectory in those who’d like to have more children. Chemo could affect fertility, though mostly in women who are mid-30s or older, Fakih said. Pelvic radiation, however, causes sterility. So, some people might first opt to freeze eggs or embryos or have surgery to shift the ovaries up and out of the path of radiation.
Reducing your risk of colorectal cancer surrounding pregnancy
The same healthy habits that may limit CRC risk at any point — being physically active, eating a nutritious diet, limiting alcohol intake, not smoking — may be especially important to consider in the years before conceiving, Ng said. Being aware of family history is also key, as it might qualify you for earlier screening, perhaps even before pregnancy, she said.
That said, many young CRC patients are healthy and do not have a family history. This makes it critical to surface any suspicious symptoms — such as bloody stools, bowel changes and belly pain — to your doctor, Ng said, even if they could be explained by pregnancy or postpartum. Be Seen, a nonprofit that Peters founded in the wake of her treatment, and the Colorectal Cancer Alliance offer resources on advocating for yourself and being taken seriously by your doctor.
The gold-standard test for CRC is a colonoscopy, which can be done safely in pregnancy but is reserved for scenarios of high suspicion because the anesthesia and procedure carry risks for the fetus, said David Greenwald, a gastroenterologist at Mount Sinai Health System.
Last summer, Collins had rectal surgery to remove a spot of recurrence. When she woke up, she found that a nurse had written “Asher’s super mommy” on a piece of medical tape securing an ice pack. She feels so lucky, she said, to still be playing that role and to be an example for her son “of what it means to go through something really challenging and come out on the other side.”
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