Can pregnant women with cancer undergo chemotherapy? Researchers say yes and provide evidence that chemotherapy and other cancer treatments do not harm the baby, according to Reuters.

Expectant mothers diagnosed with cancer can have the disease treated without having to worry about the effects of chemotherapy and other drugs on the baby's health. Cancer specialists announced Monday during the 2015 European Cancer Congress that cancer treatment of pregnant women did not affect the babies' development.

In a study involving 129 children aged one to three years old whose mothers had cancer, researchers investigated the effect of treatment on the children's mental processes and heart function. The children were exposed to chemotherapy, radiotherapy, surgery and other treatments, except for 14 whose mothers did not undergo any treatment during pregnancy.

The children were from The Netherlands, Belgium, the Czech Republic and Italy. They were matched with a control group of 129 children. Most of the mothers had either breast cancer or blood cancers.

The researchers found that the cognitive development of those who were exposed to cancer treatments was not affected. They also had no cardiac development problems. 

"Our results show that fear of cancer treatment is no reason to terminate a pregnancy, that maternal treatment should not be delayed and that chemotherapy can be given," lead researcher Frederic Amant, gynecological oncologist at the University Hospitals Leuven in Belgium and at Antoni van Leeuwenhoek in The Netherlands, said in a press release. "The study also shows that children suffer more from prematurity than from chemotherapy, so avoiding prematurity is more important than avoiding chemotherapy."

Amant said that cancer treatment could possibly trigger preterm delivery, but the real cause is yet unknown because preterm delivery was observed both for mothers who had treatment and those who did not.

"It could be that chemotherapy induces preterm contractions or vaginal inflammation with preterm rupture of the membranes," he said.

Peter Naredi, chair of the Congress, said that the study results was "reassuring for pregnant women who have been diagnosed with cancer." He emphasized the importance of starting cancer treatment early.

The study was published in the Sept. 28 issue of New England Journal of Medicine.