LONDON (AP) ― Researchers have encouraging news for women who find themselves in a very frightening situation: having cancer while pregnant. Studies suggest that these women can be treated almost the same as other cancer patients are, with minimal risk to the fetus.

Only about 1 in 1,000 pregnant women face this dilemma, but doctors fear that more will because the risk of cancer rises with age, and more women are delaying having children until they’re older.

Doctors have long worried about how to balance treating a pregnant woman with cancer and the need to protect her fetus from the effects of toxic cancer drugs and radiation treatments, and whether it is safe to continue a pregnancy in certain situations. A series of papers in the journals Lancet and Lancet Oncology published Friday make several key contributions:

― A Belgian-led study of 70 children in Europe exposed to chemotherapy while they were in the womb found they developed just as well as other children, according to tests on their hearts, IQ and general health. They were assessed at birth, 18 months, and every few years until age 18.

― 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.

“Many (doctors) aren’t keen to give chemotherapy to pregnant women and may even recommend termination,” said Dr. Frederic Amant of the Leuven Cancer Institute in Belgium, an author of two of the papers. “But treating a pregnant woman with cancer doesn’t have to be so different from treating a cancer patient who isn’t pregnant.”

Amant, who led the study of 70 children, said most of the children with cognitive problems were born premature, and that was probably the primary cause of their delayed development.

“Doctors will often err on the side of caution and deliver a baby early to avoid the effects of chemotherapy,” said Dr. Catherine Nelson-Piercy, an obstetric physician and spokeswoman for Britain’s Royal College of Obstetricians and Gynaecologists.

“These data don’t say that chemotherapy is completely safe, but the baby is better off being in (the mother) as long as possible,” she said. Nelson-Piercy was not linked to the Lancet series and often works with pregnant women diagnosed with cancer or other illnesses.

Dr. Richard Theriault, a professor of medicine at the MD Anderson Cancer Center in Texas, said he hoped the papers would change how doctors treat pregnant cancer patients.

“Terminating a pregnancy is not always necessary,” said Theriault, who heads a program to treat pregnant women with cancer. He said a minority of pregnant women with cancer still get abortions.

He said the placenta seems to act as a kind of filter for chemotherapy drugs, restricting their effects on the fetus. “There’s the phenomenon of the bald mother who gives birth to a baby with a full head of hair,” he said. “It seems to suggest not as much gets to the baby as we thought.”

That was certainly Caroline Swain’s experience, who was diagnosed with breast cancer while pregnant with her second son. She had her left breast and many lymph nodes removed and had to wait until her fetus was 12 weeks old before starting chemotherapy.

“I was just so grateful it was possible to have treatment and keep my baby,” said Swain, 45, who lives near London. “I was scared that my child wouldn’t remember me if something happened to me.”

Her son Luke, now 9, weighed in at 7.4 pounds (3.35 kilograms) when he was born, only slightly lighter than his older brother Max a year earlier.

“We had celebrations all around when Luke came out absolutely fine,” Swain said of her and her husband Rowland’s relief at the birth. “Luke is no different from his brother,” she said. “They both love Legos and X-Box.”