Dec. 13, 2010 (San Antonio) -- Pregnant women who have breast cancer shouldn’t delay chemotherapy or schedule an early delivery to avoid exposing the baby to the drugs, doctors say.
A review of the records of 313 pregnant women with breast cancer showed that nearly twice as many women who didn’t get chemotherapy had premature deliveries: 33% vs. 17% of those who took the drugs.
Premature babies face a higher risk of illness and death, says study head Sibylle Loibl, MD, of the German Breast Group.
About 2% of all breast cancers are diagnosed during pregnancy, she tells WebMD. The number may rise, however, as more women delay pregnancy until later in life, Loibl says.
Some breast cancer patients who find themselves pregnant choose to delay treatment out of fear the drugs will harm the developing fetus, according to Loibl. In such cases, doctors may induce early delivery to allow for an earlier treatment start, she says.
"That's not the right thing to do. We have shown we can give women the best treatment possible during pregnancy without putting the baby in danger," Loibl says.
The findings were presented at the San Antonio Breast Cancer Symposium.
The study included 142 women and newborns exposed to chemotherapy. Among those babies, there were four birth defects, four infections, two cases of anemia, one newborn small for gestational age, and one case of jaundice.
Among babies born to women who didn’t get chemotherapy, there was one birth defect, one case of impaired liver function, one case of low blood sugar, and one case of jaundice.
The two groups weren’t directly comparable because the women had different stages of breast cancer and received different drugs. Still, the health of the newborns was similar in both groups, says Loibl, who is continuing to monitor the children.
Steven Isakoff, MD, PhD, a breast cancer specialist at Massachusetts General Hospital Cancer Center in Boston, tells WebMD that the findings are reassuring, supporting the practice of starting chemotherapy during pregnancy.
That said, most doctors stop chemo in the 32nd or 33rd week as the drugs can cause a low white blood cell count that carries with it a risk of infection to the baby, Isakoff says. "That way, her white blood cell count will go back to normal by the time of delivery," he explains.
Also, the drugs methotrexate and gemcitabine should be avoided, particularly in the first trimester, as they affect cell division, posing a danger to new organs being formed in the fetus, says Edith Perez, MD, director of the breast cancer program at the Mayo Clinic in Jacksonville, Fla.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.