Anticonvulsants Safe During Pregnancy
Lamotrigine and levetiracetam are the safest anticonvulsants to use during pregnancy due to their lower risk of congenital malformations and adverse fetal outcomes compared to other options.
First-Line Options
Lamotrigine
- Consistently demonstrated to be among the safest medications for developing fetuses in pregnancy registries 1
- Lower risk of major congenital malformations compared to other anticonvulsants
- Better cognitive developmental outcomes in exposed children
- Important monitoring considerations:
- Clearance increases significantly during pregnancy, potentially requiring dose adjustments
- Concentrations may drop by 15-25% or more during pregnancy 2
- Monitor levels monthly, especially in each trimester
- Dose may need to be reduced quickly after delivery to avoid toxicity
Levetiracetam
- Favorable safety profile during pregnancy with minimal evidence of teratogenicity 3, 2
- Clearance increases during pregnancy, requiring monitoring
- Patients should be enrolled in the North American Antiepileptic Drug (NAAED) pregnancy registry 3
- Monitoring recommendations:
- Establish baseline levels before pregnancy
- Monitor trough concentrations during each trimester
- Consider dose adjustments if levels decrease >15-25% from baseline
Anticonvulsants to Avoid
Valproate (Highest Risk)
- Absolutely contraindicated during pregnancy 4
- Associated with serious birth defects affecting brain and spinal cord (neural tube defects)
- Occurs in 1-2 out of every 100 babies exposed during pregnancy 4
- Risk of decreased IQ, autism, and ADHD in exposed children 4
- FDA label explicitly states women who are pregnant must not take valproate to prevent migraine headaches 4
Carbamazepine
- Associated with increased risk of congenital malformations
- Potential for drug interactions with other medications needed during pregnancy 5
- Considered teratogenic, particularly when used in polytherapy 6
Other Considerations
Monotherapy vs. Polytherapy
- Monotherapy is strongly preferred over polytherapy 6, 7
- Polytherapy is associated with significantly increased risk of congenital malformations
- Use the lowest effective dose of a single anticonvulsant when possible 8
Folic Acid Supplementation
- All women taking anticonvulsants during pregnancy should receive folic acid supplementation
- Recommended dose: 5 mg/day, starting 3 months before conception and continuing through first trimester 8
- Helps prevent neural tube defects associated with anticonvulsant use
Therapeutic Drug Monitoring
- Establish baseline drug levels before pregnancy (reference concentration)
- Monitor levels regularly during pregnancy, especially for lamotrigine and levetiracetam 2
- Consider dose adjustments if:
- Levels decrease 15-25% from baseline (with risk factors for seizures)
- Levels decrease >25% from baseline (dose adjustment advised)
- Adjust doses back down after delivery, especially for lamotrigine, as levels can rise rapidly 2
Clinical Approach
- Choose lamotrigine or levetiracetam as first-line options when possible
- Use monotherapy at the lowest effective dose
- Start folic acid supplementation (5 mg/day)
- Establish baseline drug levels before pregnancy
- Monitor drug levels regularly throughout pregnancy
- Adjust doses based on levels and clinical response
- Plan for potential dose reduction immediately postpartum
- Enroll patient in pregnancy registry (NAAED: 1-888-233-2334)
Common Pitfalls to Avoid
- Using valproate in women of childbearing potential without effective contraception
- Failing to monitor drug levels during pregnancy, leading to breakthrough seizures
- Not adjusting doses downward quickly enough after delivery
- Using polytherapy when monotherapy would be sufficient
- Inadequate folic acid supplementation
- Abrupt discontinuation of anticonvulsants due to pregnancy concerns (which can lead to status epilepticus)
Remember that seizure control remains essential during pregnancy, as uncontrolled seizures pose significant risks to both mother and fetus. The goal is to balance seizure control with minimizing fetal exposure to potentially harmful medications.