II. Associated Conditions
- Catamenial Seizure
- Occurs in up to 50% of women with Epilepsy
- Seizure related to Menstrual Cycle
- Onset of Menses due to Progesterone withdrawal
- Mid-cycle at Ovulation due to Estrogen surge
- Polycystic Ovary Disease
III. Precautions: Antiepileptic Agents and Teratogenicity
- Women should not get pregnant while on most Seizure medications
- Antiepiletic agents significantly increase the risk of congenital malformation
- Lowest risk agents in women of child-bearing potential (lower Teratogenic potential)
- Moderate risk agents in women of child-bearing potential (Moderate Teratogenic potential)
- Highest risk agents in women of child-bearing potential (high Teratogenic potential)
- Unknown Teratogenic risks
IV. Management: Contraceptive Selection in Epilepsy
- Precautions
- Highly effective Contraception is critical
- See Pearls above regarding risk of congenital malformation
- Many antiepileptic medications decrease efficacy of Oral Contraceptives (see Drug Interactions)
- Highly effective Contraception is critical
- Avoid Oral Contraceptives with antiepileptics that induce CYP P450
- Agents listed below under Drug Interactions render OCPs less effective
- Oral Contraceptive failure rate with these agents >6%
- Norplant (not available in United States) also less effective with these agents
- High-dose Estrogen may be needed to suppress Ovulation
- Use 50 mcg Estrogen pill if OCP used for Contraception
- Agents listed below under Drug Interactions render OCPs less effective
- Avoid Oral Contraceptives with Lamotrigine (Lamictal) Monotherapy
- Lamotrigine clearance is increased in the presence of Estrogen containing Oral Contraceptives
- Lamotrigine when combined with Valproate is not affected by Hormonal Contraception
- Avoid Depo Provera if possible
- Both Depo Provera and many anti-epileptics increase Osteoporosis risk
- Consider non-Hormonal Contraception: Intrauterine Devices
- Copper-T IUD may be preferred
- Mirena IUD (Levonorgestrel) has higher failure rate (1.1 pregnancies per 100 woman-years)
V. Drug Interactions: Oral Contraceptives (OCP)
- Antiepileptics that induce P450 system (avoid with OCP)
- Antiepileptics that do not affect OCP efficacy
VI. Management: Pregnancy Planning
- See Preconception Counseling
- Discuss pregnancy planning >1 year in advance of planned pregnancy
- Consult neurology on transition to least Teratogenic agents
- Supplement Folic Acid
- Dose 0.4 mg/day up to doses as high as 4 mg/day in some cases
VII. Resources
- North American Antiepileptic Drug Pregnancy Registry
- https://www.aedpregnancyregistry.org/
- Women on antiepileptics should consider enrolling to allow for better studies on antiepileptic drug safety