European scientists say chemotherapy and radiotherapy are safe for unborn babies.

International studies presented at a conference in Brazil say children who are exposed to the cancer treatments while in the womb suffer no negative impacts on mental or cardiac development.

“When chemotherapy is administered after the first trimester of pregnancy, we cannot discern any problems in the children,” says lead author Dr Frederic Amant, KU Leuven and University Hospitals Leuven in Belgium.

“Fear about the risks of chemotherapy administration should not be a reason to terminate a pregnancy, delay cancer treatment for the mother, or to deliver a baby prematurely.”

Two new studies were designed to address concerns that some oncologists had about administering treatments to pregnant cancer patients.

In the first study, 38 children prenatally exposed to chemotherapy were assessed for mental development and cardiac health outcomes compared to 38 control children who were not exposed.

At around two years of age, mental development was in the normal range for both groups of children, as were cardiac dimensions and functions.

The authors say is was the first such study on the developmental outcome of children exposed to chemotherapy in utero, and shows that chemotherapy during pregnancy can be considered safe for mental development and cardiac functioning of the child.

In a second study, researchers explored the impact of radiotherapy on the children of women with cancer.

The study found that of 16 children and 10 adults who had been exposed to radiotherapy in utero; neuropsychological, behavioral and general health outcomes were within normal ranges.

One child revealed a severe cognitive delay, but this was linked to other pregnancy-related complications, the report says.

The team said it hoped the new results will provide clinicians with the evidence they need to ensure pregnant women with cancer receive the best quality care.

“It's a good feeling to know that research data can be implemented immediately into the clinic. Our data will inform physicians and patients and help them to take decisions in a difficult situation,’ Dr Amant said.

Researchers noted that long-term follow-up of children and adults whose mothers have been treated with radiation therapy during gestation would be an important step in the study, and caution should remain mandatory when giving radiotherapy to a pregnant woman.