After Cancer During Pregnancy, Infant Health Normal

Two studies published last year found good news for mothers and their babies
Breast Cancer News
March 30, 2016
Robin Warshaw, Contributing Writer, and Erin Rowley, Writer and Content Coordinator
Reviewed By: 
Erica L. Mayer, MD, MPH

An American study compared children of women with cancer who had chemotherapy after the first trimester of pregnancy to children of women who had cancer but didn’t have chemotherapy. A European study compared children of women with cancer during pregnancy to children of women who didn’t have cancer during pregnancy. In both studies, children whose mothers had cancer, whether they had chemotherapy or not, developed normally.

Background and Goals

Being diagnosed with any cancer while pregnant is rare, happening in only about 1 in 1,000 pregnancies, with breast cancer being one of the most common cancers diagnosed during pregnancy.

Many women with breast cancer need chemotherapy as part of their treatment. Doctors know chemotherapy may be harmful to a fetus during the first trimester of pregnancy, when organs are forming. Because of these concerns, some women choose to delay cancer treatment until after delivery. A provider may recommend they give birth early or terminate the pregnancy. But recent research about treating cancer during pregnancy suggests that, when the situation is handled carefully, a child is likely to develop normally despite the mother’s cancer and cancer treatments.


The American Study

This study compared two groups of mother/child pairs.

  • In both groups, the mother had cancer while pregnant. Of the 55 mothers, 32 had breast cancer.
  • In one group, of 35 children, the mothers had treatment with chemotherapy after the first trimester.
  • In the other group, of 22 children, the mothers didn’t have chemotherapy during pregnancy.

The children ranged in age from 18 months old to more than 10 years old at the time of the study. The researchers collected information about

  • whether the child was born early, or at full-term
  • mental development
  • success in school
  • behavior

The European Study

Centers in four European countries invited women diagnosed with cancer during pregnancy to have their child or children participate. More than half of the women had breast cancer. The growth and development of those 129 children was compared with the growth and development of 129 children born at the same point in pregnancy to mothers without cancer.

Of the children whose mothers had cancer during pregnancy,

  • 96 were exposed to chemotherapy, alone or with other cancer treatment, after the first trimester
  • 11 were exposed to radiation therapy, alone or with other cancer treatment
  • 13 were exposed only to surgery
  • 2 were exposed to other types of anticancer medicine
  • 14 were not exposed to cancer treatment

The researchers looked at the children’s development at 18 months of age, 36 months of age, or both. If a child was assessed at both ages, information from only one was used, along with the information of a matching child of the same age, from a mother who did not have cancer. Heart function was looked at when the child was 36 months old.

The researchers collected information about

  • birth weight
  • whether the child was born early, or at full-term
  • mental development
  • heart development and function


The American Study

This study, published in the American Journal of Obstetrics and Gynecology, found that children exposed to chemotherapy were more likely to be born early. There is no evidence the early births were caused by chemotherapy. Sometimes, pregnant women with cancer are encouraged to give birth early, though this practice is becoming less popular. Despite the higher rate of early birth, the study found no significant difference in mental ability, success in school, or behavior issues between children who were exposed to chemotherapy and children who weren’t.

The European Study

This study, published in the New England Journal of Medicine, found that babies were more likely to be born early to mothers diagnosed with cancer while pregnant. While the rate of early delivery for the general population in the countries that were included was only 6.8 to 8 percent, 61.2 percent of the women with cancer in the study had their babies early.

Although the likelihood of early birth was higher for the women diagnosed with cancer, their babies developed normally and had the same very low risk of birth defects as seen in children born early to women without cancer. Whether their mothers had cancer or not, both groups of children had the same general health, growth, mental and heart development, and heart function when tested during early childhood, including those who were exposed to chemotherapy while in the uterus.

The researchers concluded that children whose mothers had cancer while pregnant had normal development when tested at 18 months, 36 months, or both.


These studies featured women with different kinds of cancer, not just breast cancer. The American researchers noted the number of children involved in their study was small.

The European researchers noted their results may not apply to all chemotherapy medicines. They also noted that follow-up time was too short to measure long-term heart muscle damage or thinking problems.

What This Means For You

As many as 7 to 15 percent of young women with breast cancer may be diagnosed while pregnant. Reassuringly, an editorial that was paired with the European study noted the results show “treatment in the second or third trimester is likely to be best for both mothers and their offspring.”

If you were already pregnant when diagnosed with breast cancer, or became pregnant after learning you had the disease, these findings may reassure you, because they suggest that you may be able to safely treat the cancer while carrying your baby to term. You may find it especially comforting that two studies done on two different continents had similar results.

Talk with your oncologist, obstetrician and pediatrician about your specific situation. Ask about the treatments you will receive and when they will start. Talk about how you can work together to get the best breast cancer care for you while protecting your baby.

Remember that your pregnancy, and the decisions you make about it and your cancer treatment, are very personal. The choices you make may be different from others you know in the same situation, and that’s OK. Read our section, Pregnant With Breast Cancer, to learn more and find support.

Cardonick, E, Gringlas, M, Hunter, K, et al. Development of Children Born to Mothers With Cancer During Pregnancy: Comparing in Utero Chemotherapy-exposed Children With Nonexposed Controls. Am J Obstet Gynecol 2015; doi: 10.1016/j.ajog.2014.11.032.

Amant, F, Vandenbroucke, T, Verheecke, M, et al. Pediatric Outcome after Maternal Cancer Diagnosed during Pregnancy. NEJM 2015; doi: 10.1056/NEJMoa1508913

This article was supported by the Grant or Cooperative Agreement Number 1 U58 DP005403, funded by the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or the Department of Health and Human Services.

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