FOLIC ACID USE BY WOMEN WITH EPILEPSY: INTERIM ANALYSIS OF THE EPILEPSY BIRTH CONTROL REGISTRY
Authors: A. Herzog, H. B. Mandle, K. E. Cahill, K. M. Fowler, A. R. Davis, W. A. Hauser
Folic acid (FA) deficiency during early pregnancy is associated with higher risks of fetal loss and malformations. In women with epilepsy (WWE), deficiency occurs most often with the use of enzyme inducing antiepileptic drugs (EIAEDs). Neural tube malformations are most common with the use of valproate, a FA antagonist. We investigated the frequency of FA supplement use by WWE in the community and factors that may predict its use.
The Epilepsy Birth Control Registry (EBCR) is a web-based survey and educational site that gathers demographic, epilepsy, antiepileptic drug (AED), contraceptive, reproductive and FA use data from WWE in the community. These data come from the first 650 WWE, 18-47 years old, who completed the historical survey. We determined the frequency of FA use by WWE overall and stratified by at risk for pregnancy status, AED use, especially EIAEDs and valproate, contraceptive use and off contraception desiring pregnancy. WWE were considered at risk if they were sexually active and not known to have infertility, hysterectomy, tubal ligation or male partners with vasectomy. Proportions were compared by χ2 analysis. We used stepwise logistic regression to determine predictors of FA use for all WWE by demographic (age, race, education, income insurance), seizure type (generalized convulsive, complex partial, simple partial), AED (EIAED; GLUAED - glucuronidated [only lamotrigine]; NEIAED - non-EIAED; EnzInhAED - enzyme inhibiting [only valproate]; No AED), at-risk, contraceptive use (none, barrier, hormonal, IUD) and annual healthcare provider visit categories.
277 (44.7%) of the 626 respondents took FA supplement. WWE at risk, regardless of AED or contraceptive use, did not differ significantly from WWE not at risk and on no AED (Fig 1). Among WWE at risk, the frequency was higher among those who stopped contraception to become pregnant than among WWE on contraception (80.0% v 46.0%; χ2 = 4.534, p = .03). FA use by prescription did not differ between WWE at risk v WWE not at risk (48.4% v 47.8% p = NS). Education (associate college degree or higher, 48.8% v no degree, 39.0%) was the only significant demographic predictor (p = .031). Age and seizure type were not factors. AED category was a factor, (p = .040), showing less use with valproate than with EIAEDs (p = .006), GLUAEDs (p = .023) and NEIAEDs (p = .003) (Fig 2). Fewer WWE on valproate in our sample, however, had college degrees (29.5% v 50.3%; χ2 = 4.84, p = .03). There was no significant difference between WWE who did (44.4%) or did not (39.6%) see a healthcare provider during the year before the survey.
Only about half of WWE in the community take FA despite their high risk of unintended pregnancy. Rate of use is significantly higher among those with a college degree. Among AED users, valproate was associated with the lowest rate of FA use despite having the highest risk of neural tube malformations but this group in our sample also had the lowest rate of college degrees. Seeing a healthcare provider during the year before the survey did not have a significant effect.
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