Pregnancy Registries and Why They Matter in Epilepsy Care
People with epilepsy often wonder if the medication they take to control seizures is safe during pregnancy. In this Clinicians Corner blog post learn about pregnancy registries and how they can help us understand the safety of anti‑seizure medications (ASMs) during pregnancy.
Determining Anti-Seizure Medication Safety in Pregnancy
To understand if an anti‑seizure medication is safe during pregnancy, it takes data from about 10,000 pregnancies. Determining risk is even harder when someone takes more than one ASM at the same time or when only a small number of people take a specific ASM. Most healthcare providers will not see this many pregnancies during their careers.
That’s why gathering large‑scale data matters. Collecting information from many pregnancies helps researchers find possible safety risks sooner.
What is a Pregnancy Registry?
A pregnancy registry is a program where pregnant people share information about their pregnancy in a shared system. This information helps researchers better understand anti‑seizure medications, pregnancy outcomes, and infant health, including birth conditions.
What Information is Collected?
Registries can differ in the information they collect and how it’s gathered.
Some registries may focus only on pregnant people with epilepsy. Others may include those who do not have epilepsy but take an anti‑seizure medication for other reasons, such as migraine, pain, or anxiety. Some registries collect information from people in multiple countries.
Some registries collect information during pregnancy, while others collect information afterwards.
Information collected may include which medications were taken, when and how long they were used, seizure control, and pregnancy and birth outcomes.
It may also include:
- Ultrasound results
- Details about delivery (such as vaginal or cesarean birth)
- Infant Apgar scores
- Health concerns at birth
- Infant structural conditions (teratogenic malformations)
- Infant development at 3 or 12 months after birth.
The North American Pregnancy Registry
The North American Pregnancy Registry housed at Massachusetts General Brigham Hospital began in 1997. It collects information from people in the United States and Canada about structural birth conditions (or malformations) in infants born to people who take ASMs during pregnancy. It also includes a large group of volunteers who did not take ASMs during pregnancy. This group is used for comparison. To date, more than 15,500 people have joined the registry.
By collecting this information, healthcare providers and people who take ASMs can better understand which medications may be safer during pregnancy.
How to join the North American Pregnancy Registry?
To participate, individuals can call a toll‑free number (888‑233‑2334) early in pregnancy. Calling the registry serves as consent to voluntarily share your information.
What Happens After You Join?
Participants complete brief phone interviews with a study coordinator at three points.
- At enrollment
- During the final trimester of pregnancy
- About three months post-pregnancy
During these calls, participants are asked about the ASM they take, the dosage, and some background information. All information is kept private in a secure database. No individual is identified by name.
How is the Information Studied?
The information is studied separately for each medication when it is taken alone and when it is taken with other medications. An independent safety board reviews the information. If a birth condition is reported, a specialist who studies malformations (called a teratologist) reviews the medical records with the parent’s permission. The specialist does not know which ASM was taken. This helps keep the review fair.
The results are used to compare the risk of birth malformations between people who take anti‑seizure medications and those who do not.
What Have We Learned from Pregnancy Registries about Birth Conditions?
Research shows that about 1.7% of babies born to women in North America who do not have epilepsy have malformations. Research also shows that the rate of malformations is higher in pregnancies where certain ASMs are used including,
- Phenobarbital
- Topiramate
- Valproate.
These results are similar to findings from other pregnancy registries around the world, including,
- The EURAP registry (which includes data from more than 40 countries),
- Australia
- United Kingdom
- Kerala, India.
Together, these registries include people from many different racial, ethnic, genetic, and economic backgrounds.
What this Means for Pregnant People Using ASMs
It is important to remember that these findings are based on statistics, and individual experiences may vary. These results do not guarantee that a pregnancy will or will not be affected by a birth condition.
Risk can be influenced by many factors, such as
- Family history
- Folic acid use
- Medication dose or blood levels
- Other medications taken during pregnancy.
Because of this, people may want to talk with their healthcare provider about treatment options and possible risks.
The North American Pregnancy Registry has helped people better understand the risks of different ASMs during pregnancy. By joining, you can help yourself, your care team, and future families learn which medicines are safest during pregnancy.
To learn more visit www.aedpregnancyregistry.org
Author:
Patricia Penovich, MD, Chair
Minnesota Epilepsy Group (Emeritus)