Self-Assessment Questions

21. Maternal adaptations to pregnancy: II

• Your patient, K.L., is a 24-year-old with a history of epilepsy who takes a daily dose of a common antiepileptic medication. It is known to be safe in pregnancy. She has recently found out that she is pregnant and asks whether she needs to change the dose of her medication. What do you tell her? What changes during pregnancy cause you to make this recommendation?

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  Correct answer:
  During pregnancy the increased levels of circulating estrogens increase the synthesis of hepatic proteins responsible for the metabolism of several different medications, including anticonvulsant medications. In addition, the serum plasma volume increases as maternal water retention increases. Both of these physiologic changes will most likely cause a reduction in the circulating levels of anticonvulsants in the pregnant woman. K.L. is likely to require a higher level of anticonvulsant medication during pregnancy.