Merck Manual

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Seizure Disorders in Pregnancy

By

Lara A. Friel

, MD, PhD, University of Texas Health Medical School at Houston, McGovern Medical School

Reviewed/Revised Sep 2023
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The dose of antiseizure drugs may have to be increased during pregnancy to maintain therapeutic levels. If women get enough sleep and antiseizure drug levels are kept in the therapeutic range, seizure frequency does not usually increase during pregnancy, and pregnancy outcome is good; however, risks of the following are slightly increased:

Generally, uncontrolled seizures are more harmful during pregnancy than is use of antiseizure drugs Antiseizure Medications No single medication controls all types of seizures, and different patients require different medications. Some patients require multiple medications. (See also the practice guideline for the... read more ; thus, the top priority of treatment during pregnancy is to control seizures. Preconception consultation with a neurologist is recommended to stabilize maternal seizures before pregnancy. Clinicians should use the lowest possible dose of antiseizure drugs and as few different antiseizure drugs as possible.

Congenital malformations are more frequent in the fetuses of women with a seizure disorder (6 to 8%) than in fetuses of women in the general population (2 to 3%) (1 Reference Seizure disorders may impair fertility. But certain antiseizure drugs may make oral contraceptives less effective, resulting in unintentional pregnancy. The dose of antiseizure drugs may have... read more ). Risk of intellectual disability may also be increased. These risks may be related to the seizure disorder as well as use of antiseizure drugs.

Risk of hemorrhagic disease of the newborn Hemolytic Disease of the Fetus and Neonate Hemolytic disease of the fetus and neonate is hemolytic anemia in the fetus (or neonate, as erythroblastosis neonatorum) caused by transplacental transmission of maternal antibodies to fetal... read more (erythroblastosis neonatorum) may be increased by in utero exposure to certain antiseizure drugs (eg, phenytoin, carbamazepine, phenobarbital); however, if prenatal vitamins with vitamin D are taken and vitamin K is given to the neonate, hemorrhagic disease is rare.

Taken during pregnancy, phenobarbital may reduce the physiologic jaundice neonates commonly have, perhaps because the drug induces neonatal hepatic conjugating enzymes. Phenytoin is generally preferred.

All antiseizure drugs increase the need for supplemental folic acid; 4 mg is given orally once a day. Ideally, it is started before conception. Taking folic acid supplements before conception helps reduce risk of neural tube defects.

Vaginal delivery is usually preferred, but if women have repeated seizures during labor, cesarean delivery is indicated.

Antiseizure drug levels can rapidly change postpartum and should be closely monitored then.

Reference

  • 1. Artama M, Auvinen A, Raudaskoski T, et al: Antiepileptic drug use of women with epilepsy and congenital malformations in offspring. Neurology 64(11):1874-1878, 2005. doi:10.1212/01.WNL.0000163771.96962.1F

Drugs Mentioned In This Article

Drug Name Select Trade
Dilantin, Dilantin Infatabs, Dilantin-125, Phenytek
Carbatrol, Epitol , Equetro, Tegretol, Tegretol -XR
Luminal, Sezaby
Calcidol, Calciferol, D3 Vitamin, DECARA, Deltalin, Dialyvite Vitamin D, Dialyvite Vitamin D3, Drisdol, D-Vita, Enfamil D-Vi-Sol, Ergo D, Fiber with Vitamin D3 Gummies Gluten-Free, Happy Sunshine Vitamin D3, MAXIMUM D3, PureMark Naturals Vitamin D, Replesta, Replesta Children's, Super Happy SUNSHINE Vitamin D3, Thera-D 2000, Thera-D 4000, Thera-D Rapid Repletion, THERA-D SPORT, UpSpring Baby Vitamin D, UpSpring Baby Vitamin D3, YumVs, YumVs Kids ZERO, YumVs ZERO
Folacin , Folicet, Q-TABS
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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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