Women who have to undergo chemotherapy or radiotherapy while pregnant should be reassured by new research, which indicates that these cancer treatments do not affect a child's mental or cardiac development.

Some doctors may be hesitant to suggest these types of treatment if a woman is pregnant due to concerns over the potential effect they may have on an unborn baby. Belgian researchers decided to investigate this further.

In one study, they looked at 38 children who had been exposed to chemotherapy while still in the womb. Their results were compared to 38 children who had not been exposed to this treatment.

The study found that when the children were around two years old, their mental development was in the normal range, as was their cardiac development.

According to the researchers, this marks the first case control study on the developmental outcome of children who have been exposed to chemotherapy while still in the womb.

"When chemotherapy is administered after the first trimester of pregnancy, we cannot discern any problems in the children. 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,"
commented the study's lead author, Dr Frederic Amant, of KU Leuven and University Hospitals Leuven in Belgium.

In a second study, the researchers focused on radiotherapy. They looked at 16 children and 10 adults who had been exposed to this treatment while still in the womb. This marks the first long-term follow-up study of children exposed to radiation while in the womb.

It found that the participants' general health and behaviour were all within normal ranges. While one child did have severe cognitive problems, this was most likely due to other pregnancy-related complications, the researchers noted.

Dr Amant said he hoped the findings would be taken on board by doctors and patients.

"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," he added.

Details of these findings were presented at the recent European Society for Medical Oncology (ESMO) 2014 Congress in Madrid, Spain.