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Authors affiliations are listed at the end of the article.
From the University of Miami (C.L.H.), Miami, FL; University of Maryland (J.H., T.Y.T., A.K.), Baltimore; Emory University (P.B.P., K.J.M.), Atlanta, GA; New York University School of Medicine (J.A.F.), New York; Columbia University (W.A.H.), New York, NY; University of Calgary (S.W.), Alberta, Canada; Kansas University Medical Center (G.S.G.), Kansas City; Centers for Disease Control and Prevention (D.T.), Atlanta, GA; New York Medical College (B.S.K.), New York; Johns Hopkins University (P.W.K.), Baltimore, MD; Harvard Medical School (J.N.R., L.H.), Boston, MA; University of Wisconsin–Madison School of Pharmacy (B.G.); University of Tennessee Health Science Center (C.A.H.), Memphis; private practice (A.N.W.), Newport, RI; New York University (B.V.), New York; Texas A&M University Health Science Center (R.F.); University of Pennsylvania (C.L.), Philadelphia.
Address correspondence and reprint requests to the American Academy of Neurology, 1080 Montreal Avenue, St. Paul, MN 55116 guidelines{at}aan.com
| Abstract. |
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Methods: A 20-member committee including general neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and February 2008.
Results: For WWE taking antiepileptic drugs, there is probably no substantially increased risk (greater than two times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (greater than 1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. Seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84%–92%) of remaining seizure-free during pregnancy.
Recommendations: Women with epilepsy (WWE) should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high rate (84%–92%) of remaining seizure-free during pregnancy (Level B). However, WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery during pregnancy (Level C).
Abbreviations: AAN = American Academy of Neurology; CI = confidence interval; OR = odds ratio; RR = relative risk; WWE = women with epilepsy.
This parameter and the two companion parameters are updates of the previous practice parameter from 1998.4 They employ improved methodology for the development of practice parameters to analyze a large number of new studies informing the clinical management of WWE who are pregnant or plan pregnancy.
This parameter summarizes evidence for two broad clinical questions:
| DESCRIPTION OF THE ANALYTIC PROCESS |
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Literature review and article selection. A literature search was performed using MEDLINE, MEDLINE-In-Process, Current Contents, Biologic Abstracts, and BIOSIS previews for relevant articles published between 1985 and December 2005. An updated search was performed from December 2005 through June 2007, with manual searches on some topics through February 2008. The arbitrary cutoff date of 1985 was chosen because these relatively recent articles were thought to reflect current practice and AED usage patterns and therefore be more applicable and reliable for this assessment than earlier reports. The search terms used were seizures/epilepsy, catamenial epilepsy, pregnancy, anticonvulsants, antiepileptic drugs, teratogenesis, birth defects, pregnancy registry, cognitive outcome, vitamin K, folate/folic acid, breastfeeding, oral contraceptives, polycystic ovary syndrome, hormone replacement therapy, menopause, perimenopause, and fertility. The search was confined to articles using human subjects and included all languages for which there was an abstract in English. A secondary search for missed references was done by reviewing the bibliographies of review articles and meta-analyses identified in the primary search.
The literature search yielded a total of 876 abstracts. To find relevant articles, two panel members screened each of the abstracts. If either panel member thought the article was potentially relevant, the full text was obtained for review. In general, abstracts were excluded from further analysis if they related to eclampsia rather than seizures due to epilepsy, related to basic mechanisms such as teratogenesis or placental AED metabolism, or were unrelated to the questions posed by the panel.
From the abstracts, a total of 285 were selected for complete review. Four panel members reviewed the full text of the articles and identified those that were relevant to each clinical question. Articles were included in the analysis of this article if they determined the frequency of pregnancy-related or epilepsy-related complications in a cohort of pregnant WWE. Articles relevant to the clinical questions of the companion articles were included in the appropriate article and are described there.
Study classification and measures of effect. With the exception of the question pertaining to recurrent seizures in seizure-free WWE, articles were classified according to the AAN prognostic classification of evidence scheme (appendix e-4A on the Neurology® Web site at www.neurology.org). Articles regarding recurrent seizures in seizure-free WWE were classified according to the AAN screening classification of evidence scheme (appendix e-4B). This scheme was chosen because the absolute risk of seizure recurrence, rather than the relative risk, was deemed most clinically relevant to this question. Articles were classified separately by four panel members. Disagreements on categorization of the articles were resolved by discussion and consensus.
For pregnancy-related complications, studies were given a lower class of evidence when they did not compare complication frequencies in pregnant WWE to pregnant women without epilepsy. For epilepsy-related complications, studies were given a lower class of evidence when they did not compare complication frequencies in pregnant WWE to nonpregnant WWE.
Additionally, studies were downgraded for a lack of masked outcome assessment or if they provided insufficient information to determine relative risk (RR) or odds ratios (ORs). The requirement for masked outcome assessment was waived for obviously objective outcomes such as cesarean delivery, preeclampsia, pregnancy-induced hypertension, spontaneous abortion, and status epilepticus. Meta-analyses were not performed due to heterogeneity of the studies.
When possible, the associations between epilepsy and pregnancy-related complications or pregnancy and epilepsy-related complications were determined using ORs. If not reported in the article, the writing panel attempted to calculate the appropriate ORs. For the only Class I article,5 the authors were personally contacted to provide further detail on data reported in the article. To allow calculation of the OR when one of the cells of the two by two table was zero, 0.5 was added to each cell.6
For the purposes of this parameter, a moderately increased risk is defined by an OR of greater than 1.5 and less than 2.0 and a substantially increased risk by an OR of 2.0 or greater.
The 95% confidence intervals (CIs) of the ORs were used as the measure of precision. Negative studies were judged to be sufficiently sensitive to exclude an increased risk based on the upper limit of the 95% CIs. Thus, a study failing to show a significant increased risk of a complication based on an OR of 1.2 with 95% CIs of 0.6 to 1.7 would be judged to be too insensitive to exclude a moderately increased risk of the complication.
The strength of the practice recommendations was directly linked to the class of evidence using the scheme described in appendix e-5.
| ANALYSIS OF EVIDENCE |
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Cesarean delivery. One Class I study5 did not show a significant increased risk of cesarean delivery in WWE taking AEDs compared to women without epilepsy (OR 1.04, 95% CI 0.71–1.52). A Class II study7 did not show a significant increased risk of cesarean delivery in WWE compared to women without epilepsy (OR 1.24, 95% CI 0.99–1.55). However, both studies were insufficiently sensitive to exclude a moderately increased risk.
Three Class III studies (OR 17.88, 95% CI 4.73–67.588; OR 1.58, 95% CI 1.10–2.259; and OR 2.2, 95% CI 1.42–3.4110) demonstrated a significant substantial increased risk.
Other than the increased risk of bias and statistical imprecision of some studies, there is little information to explain the increased cesarean delivery rate observed in the Class III studies compared to the Class I and II studies.
Conclusion.
Based on evidence from one Class I and one Class II study, it is probable that WWE taking AEDs do not have a substantially increased risk of cesarean delivery. Because of the lack of statistical precision in the Class I and Class II studies and the evidence from multiple Class III studies, a moderately increased risk of cesarean delivery is possible.
Preeclampsia. One Class I study5 did not show a significant increased risk of preeclampsia in WWE taking AEDs compared to women without epilepsy (OR 1.4, 95% CI 0.66–3.15). However, this study was insufficiently sensitive to exclude an increased risk.
Two Class II studies (RR = 0.8, 95% CI 0.2–2.911 and OR 1.24, 95% CI 0.77–1.997) did not observe a significant increase in the risk of preeclampsia in WWE compared to women without epilepsy. These studies were insufficiently sensitive to exclude an increased risk.
Conclusion.
There is insufficient evidence to support or refute an increased risk of preeclampsia in WWE taking AEDs.
Pregnancy-induced hypertension. One Class II study (OR 1.4, 95% CI 1.1–1.9)7 showed an increased risk of pregnancy-induced hypertension in WWE as compared to women without epilepsy. Another Class II study (OR 0.7, 95% CI 0.3–1.6)11 showed no significant increased risk but was insufficiently sensitive to exclude a moderately increased risk.
Two Class III studies (OR 7.8, 95% CI 0.8–76.98 and OR 1.2, 95% CI 0.7–2.110) demonstrated no significant increased risk. These studies were insufficiently sensitive to exclude a substantially increased risk.
Conclusion.
Based on results from two conflicting Class II studies, there is insufficient evidence to support or refute an increased risk of pregnancy-induced hypertension in WWE.
Premature contractions and premature labor and delivery. One Class I study5 showed no substantially increased risk of premature contractions or premature labor and delivery in WWE taking AEDs compared to control women without epilepsy (OR 0.51, 95% CI 0.19–1.36).
One Class II study12 showed an increased risk for WWE who were smokers compared to control women who were also smokers (OR 3.4, 95% CI 1.8–6.5) (data not given for all WWE compared to controls). One Class III study13 also showed an increased risk (p < 0.05). Another Class III study8 demonstrated no significant increased risk but was insufficiently sensitive to exclude a substantially increased risk (OR 8.24, 95% CI 0.92–70.32). A Class III study11 showed no significant increased risk but was not sufficiently sensitive to exclude an increased risk (RR 0.7, 95% CI 0.3–1.4). In a categorical,
2 statistic, it was reported that the rates of premature births were not different than controls (p = 0.3),9 and another study found no differences in gestational ages in the offspring of WWE compared to controls (WWE = 38.06, SD 1.42 vs controls = 38.17, SD 3.58 weeks).10
Conclusions.
Based on evidence from one Class I study, it is probable that WWE taking AEDs do not have a moderately increased risk of premature contractions and premature labor and delivery during pregnancy. However, based on evidence from one Class II study, it is possible that WWE who smoke do have a substantially increased risk of premature contractions and premature labor and delivery during pregnancy compared to women without epilepsy who smoke.
Pregnancy-related bleeding complications. One Class I study5 did not show a significant increased risk of late pregnancy bleeding in WWE taking AEDs compared to women without epilepsy (OR 1.18, 95% CI 0.70–1.97). One Class III study11 also demonstrated no increased risk (RR 0.9, 95% CI 0.4–2.0). However, neither study was sufficiently sensitive to exclude a moderately increased risk.
Conclusion.
Based on evidence from one Class I and one Class III study, it is probable that WWE taking AEDs do not have a substantially increased risk of late pregnancy-related bleeding complications. However, because of a lack of statistical precision in these studies, a moderately increased risk cannot be excluded.
Spontaneous abortion. One Class III study14 showed a decreased risk of spontaneous abortion in WWE compared to controls (6.9% vs 7.5%). No denominator is provided for the control group to allow calculation of ORs.
Conclusion.
The data are inadequate to support or refute an increased risk of spontaneous abortion in WWE.
Do WWE have an increased risk of epilepsy-related complications during pregnancy? Twenty-five articles met inclusion criteria for epilepsy-related complications in pregnant WWE.
Change in seizure frequency. No study compared the change in seizure frequency in pregnant WWE to nonpregnant WWE; therefore an appropriate gold standard comparator group was not available. Hence, all studies were graded Class IV (table e-2). Three articles15–17 used each patients nonpregnant seizure frequency (per pregnancy) as its own control. In one study, which evaluated 154 pregnancies,15 seizure frequency was unchanged in 54% (95% CI 0.46–0.62) (including 48 [31%] seizure-free patients), decreased in 14% (95% CI 0.10–0.21), and increased in 32% (95% CI 0.25–0.40) compared to prepregnancy seizure frequency. In this study, AED doses were increased when seizure frequency increased.
In another study, which evaluated 78 pregnancies,16 seizure frequency was unchanged in 72% (95% CI 0.61–0.81) for major seizures (Wilcoxon test p > 0.50 for significant differences), decreased in 14% (95% CI 0.08–0.24), and increased in 14% (95% CI 0.08–0.24) compared to prepregnancy baseline. AED doses were increased when seizure frequency increased in this study as well.
In a third Class IV study, which evaluated 93 pregnancies,17 seizure frequency as a whole was not different in pregnancy compared to baseline (p = 0.42). The exact numbers were not provided, but the percent change was reported as the following: 61% unchanged, 24% decreased, 15% increased. Seizure increase was more likely in partial epilepsy (29%) than idiopathic epilepsy (7%). AED doses were unchanged in this study.
Another Class IV study18 used both retrospective recall and postpartum prospective seizure frequency as comparators. In this study of 74 AED-compliant patients, seizure frequency was unchanged in 80% (95% CI 0.69–0.87), decreased in 4% (95% CI 0.01–0.11), and increased in 16% (95% CI 0.01–0.26). AED doses were unchanged in this study.
Another article19 used postpartum seizure frequency as a comparator. In this study of 138 pregnancies, seizure frequency was unchanged in 80% (95% CI 0.72–0.86), decreased in 3% (95% CI 0.01–0.07), and increased in 17% (95% CI 0.12–0.25). The AED management was not stated in this study.
The percentage of patients with unchanged seizure frequency in these studies ranged from 54% to 80%. The highest rate of unchanged seizure frequency was the 80% reported in AED-compliant patients, documented by serum levels.18 The rate of seizure decrease ranged from 3% to 24%. The rate of seizure increase ranged from 14% to 32%.
Unfortunately, none of these studies included an appropriate nonpregnant WWE comparator group to provide information on the natural stability of seizure frequency among WWE. Without this information, it is impossible to determine if the changes in seizure frequency observed were related to the pregnancy itself.
Conclusion.
There is insufficient evidence to determine the change in seizure frequency in pregnant WWE.
Status epilepticus. No studies compared the risk of status epilepticus in nonpregnant WWE to pregnant WWE. Hence, all studies were graded Class IV (table e-3). Three population-based studies reported a frequency of status epilepticus in WWE during pregnancy of 0%–1.3% (0/154, 0%, 95% CI 0.00–0.315; 1/78 convulsive status epilepticus, 1.3%, 95% CI 0.00–0.0716; and 0/89, 0%, 95% CI 0.00–0.0417). Similarly, a large prospective, but not population-based, study of nearly 2,000 pregnancies20 found status epilepticus in 36/1,956 (1.8%, 95% CI 0.01–0.03) pregnancies. Twelve of these 36 episodes of status epilepticus were convulsive and 24 were nonconvulsive.
Although there is no accurate information in a similar population of persons with epilepsy to use as a historical comparator, these estimates closely approximate an annual frequency of 1.6% for status epilepticus reported in a large series of patients with varied epilepsy types.21 This comparison suggests that status epilepticus does not occur more frequently during pregnancy. However, the absence of a comparison group of nonpregnant WWE within these studies makes it impossible to determine the relative risk of status epilepticus during pregnancy.
Conclusion.
There is insufficient evidence to support or refute an increased risk of status epilepticus in pregnant WWE.
Seizure recurrence in previously seizure-free WWE. Two Class II articles16,17 showed that for WWE who were seizure-free for 9 months prior to pregnancy, 84%–92% remained seizure-free during pregnancy (table e-4). In one study, 38 of 45 (84%; CI 0.71–0.92) pregnant WWE remained seizure-free,16 and in the other study, 47 of 51 (92%; CI 0.82–0.97) pregnant WWE remained seizure-free.17
One larger Class III article22 showed that 80% of a group of WWE (n = 450) who were seizure-free at least 1 year prior to pregnancy remained seizure-free during pregnancy (exact number not provided). One Class III article showed that of 72 WWE who were seizure-free for 10 months, 74% (95% CI 0.62–0.82) remained seizure-free during pregnancy.18 A second Class III article showed that of 54 WWE who were seizure-free for 9 months, 94% (95% CI 0.85–0.98) remained seizure-free during pregnancy, and of 48 WWE who were seizure-free for 1 year, 92% (95% CI 0.80–0.98) remained seizure-free during pregnancy.19 These results are all fairly consistent across the class of evidence and sample size of the studies.
Conclusion.
Two Class II articles show the rate of remaining seizure-free during pregnancy if WWE are seizure-free for at least 9 months to 1 year prior to pregnancy is probably 84%–92%.
| RECOMMENDATIONS |
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| CLINICAL CONTEXT |
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Further, the findings do not suggest high rates of seizure increase or status epilepticus during pregnancy or an increased risk of seizure relapse during pregnancy for WWE who are seizure-free. The data available to determine how seizure-free WWE fare during pregnancy indicate it is likely that they will remain seizure-free, providing practitioners with another reason to strive for seizure freedom in their patients planning pregnancy.
It is hoped that this information will herald a new outlook about how high (or low) the actual risk is for health complications in WWE who become pregnant, and may serve to decrease the anxiety and perhaps the stigma produced by this clinical situation for both patient and practitioner.
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| ACKNOWLEDGMENT |
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| DISCLOSURE |
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| DISCLAIMER |
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Supplemental data at www.neurology.org
e-Pub ahead of print on April 27, 2009, at www.neurology.org.
Published simultaneously in Epilepsia.
The Mission Statements of the Quality Standards Subcommittee (QSS) and Therapeutics and Technology Assessment (TTA) Subcommittee, Conflict of Interest Statement, QSS members, TTA members, AAN classification of evidence, Classification of recommendations (appendices e-1 through e-5), as well as tables e-1 through e-4, are available as supplemental data on the Neurology® Web site at www.neurology.org.
Approved by the Quality Standards Subcommittee November 5, 2008; by the Therapeutics and Technology Assessment Subcommittee November 15, 2008; by the Practice Committee December 18, 2008; and by the AAN Board of Directors March 25, 2009.
Supported by The Milken Family Foundation.
Disclosure: Author disclosures are provided at the end of the article.
Received December 19, 2008. Accepted in final form March 23, 2009.
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