Chemo during pregnancy not detrimental

Despite the occurrence of more neonatal and obstetrical events in women receiving chemotherapy during pregnancy than in those who wait until after, a recent study in the online edition of the August 16, 2012 Lancet Oncology finds the differences clinically insignificant. Researchers say that differences in outcomes are more the result of premature delivery than they are of chemotherapy.

After adjusting for gestational age, the researchers found that birth weight was affected by chemotherapy exposure, but not by number of cycles. They also found no statistical difference between the 2 groups for premature deliveries before the 37th week. About half of the women delivered preterm, about one-quarter of whom delivered before the 35th week. In comparison, about 10% to 15% of all infants are born before the 37th week of gestation. In this study, preterm delivery was more common in women who delayed chemotherapy than in those who began treatment while pregnant.

Ten percent of the infants born had side effects, malformations, or newborn complications consistent with those seen in the general population. These events were about 3 times as common in the infants born before 37 weeks’ gestation as in those born later. Adverse events were about 4 times more common in the women who received chemotherapy during pregnancy than among those who didn’t. The researchers believe that most of the malformations were a result of premature delivery and not chemotherapy exposure because malformations occur only during the first trimester and the chemotherapy was administered in other trimesters.

Interestingly, taxanes are generally not recommended for use during pregnancy, but this study showed no difference in complications in infants exposed to those drugs versus other forms of chemotherapy.  

The study appeared in the online edition of the Lancet Oncology.

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