Women With Epilepsy: a Pilot Study of PK and PD Anti-epileptic Drug Effects in Levonorgestrel Intrauterine System Users

The investigators will conduct a prospective, seven-month pilot study to explore pharmacokinetic (PK) and pharmacodynamic (PD) effects among women with epilepsy using the levonorgestrel intrauterine system (LNG IUS) for contraception. The investigators will enroll twenty women with well-controlled epilepsy maintained on stable anti-epileptic drugs (AED) therapy seeking the LNG IUS for contraception. The primary outcomes are AED levels and seizures before and after LNG IUS placement. Secondary outcomes include LNG levels, evidence of ovulation three weeks after insertion (serum progesterone \>3ng/ml), bleeding and spotting, endometrial thickness, continuation, satisfaction and adverse events (removals, expulsions, side effects). The investigators will conduct a baseline month assessment, insertion visit, and follow-up visits at 21 days, three months and six months.