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Is Pregnancy Safe for Breast Cancer Survivors?

Is Pregnancy Safe for Breast Cancer Survivors?

Published on December 17, 2020

New Research Examines Pregnancy Outcomes in Breast Cancer Survivors

Most breast cancer survivors who become pregnant deliver healthy babies, according to data presented at the 2020 San Antonio Breast Cancer Symposium (SABCS). And while women who develop breast cancer are less likely to become pregnant than the general population, pregnancy appears to have no adverse effects on their long-term survival.

"With the availability of more effective anticancer treatments, survivorship has gained substantial attention,” said corresponding study author Dr. Matteo Lambertini, an adjunct professor in medical oncology at the University of Genoa – IRCCS Policlinico San Martino Hospital in Genoa, Italy.

“Today, returning to a normal life after cancer diagnosis and treatment should be considered as a crucial ambition in cancer care. In patients diagnosed during their reproductive years, this includes the possibility to complete their family planning,” Dr. Lambertini added in a release announcing the findings.

According to the Susan G. Komen Foundation, breast cancer is the most common cancer in pregnant and postpartum women, with approximately one case of breast cancer diagnosed per 3,000 pregnancies each year.

As the average age for pregnancy has risen over time, it has become more common for women to be diagnosed with breast cancer before having a child, Dr. Lambertini explained. The average age of first-time mothers in the United States is now 26 — up from 23 in 1994. For the study, researchers conducted a systematic literature review of 39 studies that identified women who had been pregnant after a breast cancer diagnosis (n=114,573).

Compared with women from the general population, patients who had gone through breast cancer had a 60% reduced chance of becoming pregnant, though some of these women may not have tried to conceive after their diagnosis. Many of the anticancer therapies that have successfully reduced breast cancer mortality have possible long-term toxic effects, including infertility, Dr. Lambertini noted. He estimates that more than half of young women who tried to conceive did so, while some women who did not plan to become pregnant did.

Are There Risks to Pregnancy After a Breast Cancer Diagnosis?

Becoming pregnant after a breast cancer diagnosis is not without its risks. Compared to women in the general population, breast cancer survivors had a 50% percent higher risk of having a baby with low birth weight; 16% higher risk of having a baby that was small for gestational age; a 45% higher risk of preterm labor; and a 14% higher risk of having a cesarean section, according to the study.

Still, there was no significant increased risk of congenital defects or other pregnancy or delivery complications. Furthermore, the increased risk of low birth weight and small size for gestational age appeared to apply mainly to women who had received chemotherapy.

The analysis further indicated that pregnancy appeared safe across BRCA status, nodal status, previous chemotherapy exposure, pregnancy interval (the amount of time between breast cancer diagnosis and pregnancy) and pregnancy outcomes.

Does Pregnancy Impact Breast Cancer Prognosis?

The study found that pregnancy was not associated with poor patient outcomes. Those who did get pregnant had a 44% reduced risk of death and a 27% reduced risk of disease recurrence compared to patients who did not. When controlling for the "healthy mother effect," which suggests that women who feel well and have good prognoses are the most likely to try to conceive, women who became pregnant had a 48% reduced risk of death and a 26% reduced risk of disease recurrence.

In a nutshell: Pregnancy after breast cancer is safe and does not negatively impact patients' prognoses. However, the higher risk of delivery and fetal complications indicates that healthcare providers should more closely monitor pregnant breast cancer survivors than healthy pregnant women from the general population.

Watch Dr. Lambertini’s presentation here. Find Dr. Lambertini’s abstract here.

~Megan Trusdell


  • Breast Cancer Survivors Are Less Likely to Get Pregnant, but Often Have Healthy Babies and Good Long-term Health
  • Pew Research Center: 6 facts about U.S. moms

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