Pharmacokinetic considerations in the use of anticancer drugs during pregnancy: challenges and new developments.

Cancer complicates approximately 0.1% of all pregnancies, and the incidence is expected to increase, as more women elect to defer child-bearing to a later age. For these women and the clinicians treating them, there is little rigorous evidence with which to guide their management, but thought must be given to the effects of chemotherapeutic agents on the developing fetus and the effects of physiological changes within the pregnant women. We examine the evidence available for the effects of cytotoxic chemotherapy on the development of the fetus and for the health of the child in the longer term, and the effects of transplacental transfer and physiological changes of pregnancy on the pharmacokinetics of these drugs. These factors may have significant influence on the appropriate dosing of chemotherapeutic agents in pregnant women, compared to their nonpregnant counterparts, and further research is required into the implications of these findings for the successful treatment of cancer in pregnancy.