Blood levels of some epilepsy medicines lower during pregnancy

1 Mar 2022

The amount of some epilepsy medicines in the blood drops in women during pregnancy, according to a new study in JAMA Neurology.

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study, by Page Pennell and her colleagues, investigated the pregnancy-associated changes in several epilepsy medicines. These were lamotrigine, levetiracetam, lacosamide, oxcarbazepine, zonisamide, carbamazepine and topiramate.

Reduced levels of epilepsy medicines in the blood during pregnancy can lead to more frequent or severe seizures which could be harmful to the woman and baby.

The research included 430 participants – 326 pregnant women with epilepsy (the study group) and 104 women with epilepsy who were not pregnant for comparison (known as controls) – aged 14-45 years. The pregnant women were at less than 20 weeks of pregnancy when the study started. The study group was monitored for nine months after giving birth, with a similar timeframe used for the control group.

In the study group, blood tests were done four times during pregnancy and three times after the women had given birth. Seven blood tests were also done in the control group over 18 months.

Amounts of epilepsy medicines in the blood were compared during and after pregnancy in the study group, and between the study and control groups.

When comparing the blood levels during and after pregnancy in the pregnant women group, levels of many of the epilepsy medicines were significantly reduced during pregnancy. Lamotrigine levels decreased by over a half (56.1%) and levetiracetam by over a third (36.8%). Oxcarbazepine reduced by around a third (32.6%), as did zonisamide (29.8%), and lacosamide levels dropped by two-fifths (39.9%). The authors say that monitoring of medicine levels in the blood should start early in pregnancy, and that increasing the doses of some epilepsy medicines may be needed throughout pregnancy.

There is more information about epilepsy, medicines and pregnancy on the Epilepsy Action website.


You may also be interested in…

Trend towards use of safer epilepsy medicines in pregnancy, studies show

Over the last 20 years, there has been an increase in the use of epilepsy medicines known to be safer in pregnancy among pregnant women.

There are no comments yet. Be the first to comment...

Question about your epilepsy?

Your question will be sent to our helpline advisors.

Have a comment about this page?

All comments are reviewed by a moderator before publishing. Comments will be edited or deleted if they are offensive, libellous, slanderous, abusive, commercial or irrelevant.

We ask for your email when you make a comment through this website. This means that we can let you know directly that we have replied to you. By making a comment through the website, you allow us to use the comment in our publicity without using your name. If we would like to use your name, we will email you to get your permission.

The content of this field is kept private and will not be shown publicly.
This question is for testing whether you are a human visitor and to prevent automated spam submissions.
4 + 9 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.