Use of Oral Contraceptives by Women With Epilepsy-Reply

Abstract

In Reply.— Dr Elkington makes two important comments in his letter discussing our article. All antiepileptic drugs have teratogenic potential, and neural tube defects may be more likely with valproic acid ingestion. The use of valproic acid was recommended in conjunction with oral contraceptives because it is not an enzyme inducer and women using these two drugs are highly unlikely to become pregnant, so the teratogenic risk is small. As for the use of alternative oral contraceptives in breakthrough bleeding, our practice has been to begin by elevating the estrogen dose over the minimum level used in the general population. The concept is to use breakthrough bleeding as a guide for contraceptive efficacy. Although we have avoided the use of progestins to overcome what is seen as a failure of estrogen effect 1 and because progestins may have their own ill effects, 2 we cannot quarrel with avoidance of the