Children born to women receiving chemotherapy during the middle and end of pregnancy show normal development, European researchers have found.

When a pregnant women is diagnosed with cancer, she and her oncologist and obstetrician face complicated decisions about treatment. It's known that giving chemotherapy in the first 12 weeks of pregnancy when the baby's organs are developing raises the risks of birth defects.

Chemotherapy after the first trimester is possible, using extra ultrasounds to ensure the baby is developing properly, researchers say. (Joshua Lott/Reuters)

To see whether chemotherapy and radiation harm the developing fetus after that point, Dr. Frédéric Amant, a gynecologic oncologist at Katholieke Universiteit in Leuven, Belgium, and investigators in the Netherlands and Czech Republic examined medical records and tested 70 children whose mothers received cancer treatment.

The women received three or four cycles of chemotherapy. Their children were assessed at birth, 18 months and every few years until age 18, a longer time period than in previous studies.

"Treating a pregnant woman with cancer doesn't have to be so different from treating a cancer patient who isn't pregnant," Amant said.

The children weren't at higher risk of heart, hearing or nervous system disorders, or general health and growth problems compared with a control group of babies. Study authors Dr. Wei Hui and Luc Merton of Toronto's Hospital for Sick Children compared the cardiac measurements of Belgian participants and controls.

Premature births

"Our findings suggest that general health and growth, and central nervous system, cardiac and auditory function of children born to mothers treated with chemotherapy during pregnancy did not differ from the general population," the study's authors concluded.

One of the issues raised by the authors is whether pregnancy should be induced early for women receiving chemotherapy.

"These data don't say that chemotherapy is completely safe, but the baby is better off being in [the mother] as long as possible," said Dr. Catherine Nelson-Piercy, an obstetrician and spokeswoman for Britain's Royal College of Obstetricians and Gynecologists who was not part of the study.

Most of the children with cognitive problems were born prematurely, which was probably the main cause of their delayed development, Amant said.

Nelson-Piercy often works with pregnant women diagnosed with cancer or other illnesses.

'Reassuring' for pregnant women with cancer

The findings could affect clinical practice, Dr. Elyce Cardonick of the department of obstetrics and gynecology at Cooper Medical School of Rowan University in New Jersey said in an editorial in the journal.

"If we can present this reassuring data to pregnant women with cancer, women might be more likely to accept treatment during pregnancy when indicated," Cardonick said.

The study was part of a series by the journals Lancet and Lancet Oncology on cancer in pregnancy.

Other highlights included:

• Chemotherapy after the first trimester is possible, using extra ultrasounds to ensure the baby is developing properly. Radiation therapy is best done in the first two trimesters, when the baby is small enough to be covered with a lead blanket, according to a review of previous studies, led by Belgian researchers. Ending the pregnancy doesn't improve chances for the mother, the same study found.
• The type of cancer seems to matter: An Israeli analysis of past research suggested pregnant women with blood cancers might want to terminate an early pregnancy when chemotherapy can't be delayed.
• Another review of previous studies by French and American researchers concluded doctors should aim to preserve pregnancy in women with cervical or ovarian cancers where possible.

With files from The Associated Press