A protocol design for studying alterations of pharmacokinetic parameters due to pregnancy.

A study protocol is described by means of which useful and pertinent information on possible alterations of pharmacokinetic parameters due to pregnancy can be investigated. Whenever any drug is prescribed to a pregnant woman for medical reasons, pharmacokinetic data for that drug can be obtained by determination of drug levels in urine, plasma or serum, or other possible tissues. The same data should later be obtained for an identical dose of the same drug given to the same woman after pregnancy. By comparing pharmacokinetic parameters in the same woman during pregnancy and after--when she serves as her own nonpregnant control--clinically and statistically significant differences may be discovered with a comparatively small patient material. As in each case the drug that is studied is prescribed for medical reasons, this protocol involves no undue risks for the pregnant woman or the fetus.