Cancer Treatment in Pregnancy Found Safe for Babies

A new study has good news for those diagnosed with cancer while pregnant: cancer treatments during pregnancy have no long-term health risks to children.

Cancer Treatment in Pregnancy Safe for Babies Photographee.eu/Shutterstock

Being diagnosed with cancer is hard enough, but being diagnosed with cancer during pregnancy brings a whole other level of anguish and concern for your unborn child. Whether to treat the disease while pregnant is a difficult decision, and women in the past were often counseled to terminate their pregnancies in order to begin treatment. Fortunately, times have changed, and new research published this week in The New England Journal of Medicine shows that chemo and other therapies have no effect on children several years after birth.

No negative effects seen in toddlers

Researchers looked at 129 European children whose mothers had cancer during pregnancy, mainly breast cancer and blood cancers like leukemia, and most of whom underwent treatment such as chemotherapy. Those children were matched with a control group whose mothers did not have cancer. The study followed the children's development at 18 months and three years, and found that the exposure to cancer treatments did not have any effect on their mental, cardiac or general development. "We show now in this study that chemotherapy is safe during pregnancy," lead author Dr. Frédéric Amant, M.D., Ph.D., a gynecological oncologist at the University Hospitals Leuven in Belgium, tells Fit Pregnancy from the 2015 European Cancer Congress in Vienna.

However, children whose mothers had cancer were more likely to be born premature, usually because of a medical decision to deliver early in order to continue treatments—and prematurity was shown to be associated with cognitive delays. "Chemotherapy does not affect the cognitive outcome but prematurity does," Amant says. "So the fact that we can treat cancer during pregnancy means that we can give chemo or surgery or radiotherapy in order to continue the pregnancy until the fetus is mature, and avoid prematurity."

The study looked specifically at the children's mental development, as well as heart function. "Of course cognitive development is very important for children, and we looked at cardiac function because some of the drugs which are commonly used can be toxic for the heart," Amant says. "In adults who receive this chemotherapy, it can provoke heart insufficiency and so we were concerned about the fetal effects. It was reassuring that the heart function in these children was normal."

But because new chemotherapy drugs are being developed all the time, this study can't say definitively that all cancer medications are safe. And the study only looked at women who were treated in the second and third trimesters—treatment in the first trimester is still not recommended because it's such a critical period of development for the baby. Since his research didn't examine it, "we cannot say that chemotherapy during the first trimester is safe," Amant says.

More options for pregnant women with cancer

In the past, it was assumed that all cancer drugs were toxic to baby, and termination was often recommended. "That was mainly because of the lack of data—they say 'OK, as long as you cannot show proof via a good study that this is safe then we will go for the mother and we won't take any risks,'" Amant says. "What we hope to do now is give solid data so they can't use that argument anymore. We do hope that this will change the clinical practice." Amant says there isn't data on how common termination was, mainly because there was no obligation to report it, and there wasn't enough communication between doctors in oncology and obstetrics.

According to the American Cancer Society, recent studies have proven that cancer treatments don't raise the risk of birth defects, stillbirth or health problems shortly after birth, so termination is no longer routinely recommended. But, the ACS notes there hasn't been much information on the possible long-term risks on children exposed to cancer treatments—until now. "There was research on this topic but there was never a control group so the comparison was never as good as it is now," Amant says.

If you are one of the one in 1,000 women diagnosed with cancer during pregnancy and your doctor advises you to terminate, you should seek a second opinion. "I can imagine there are some situations where you'd terminate the pregnancy but I think this is really a vast minority," he says. "The vast majority we can treat during pregnancy, so if termination of pregnancy is proposed I think you deserve to be counseled why this is, and if there's any doubt you should go to other physicians who have more experience."

Amant says his work is just part of much-needed research about the safety of medications for pregnant women. "Overall there is little research on drugs during pregnancy," he says. "The drugs that are most notorious for their toxicity we've proven are safe, so maybe this will motivate other groups to investigate safety of [more] drugs. I think pregnant women deserve more research."

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