Tysabri and Foetal malformation - a phase IV clinical study of FDA data

Summary:

Foetal malformation is reported as a side effect among people who take Tysabri (natalizumab), especially for people who are 50-59 old, have been taking the drug for 2 - 5 years also take Cetirizine Hydrochloride, and have Drug exposure during pregnancy.

The phase IV clinical study analyzes which people have Foetal malformation when taking Tysabri. It is created by eHealthMe based on reports of 220,870 people who have side effects when taking Tysabri from the FDA, and is updated regularly.

What is Tysabri?

Tysabri has active ingredients of natalizumab. It is often used in multiple sclerosis. eHealthMe is studying from 221,369 Tysabri users. Check the latest studies of Tysabri.

What is Foetal malformation?

Foetal malformation (birth defect abnormal or anomalous formation or structure) is found to be associated with 76 drugs and 114 conditions by eHealthMe. Check the latest studies of Foetal malformation.

On Aug, 11, 2026

220,870 people reported to have side effects when taking Tysabri.
Among them, 13 people (0.01%) have Foetal malformation.

Could Tysabri cause Foetal malformation?

Among these 13 people:

How long have people been on Tysabri when they have Foetal malformation? *

What is the age of people who have Foetal malformation when taking Tysabri? *

What are other drugs people take besides Tysabri? *

Hydroxyzine: 2 people, 15.38%
Cetirizine Hydrochloride: 2 people, 15.38%

What are other side effects people have besides Foetal malformation? *

Foetal Exposure During Pregnancy (exposing your unborn child to contraindicated in pregnancy leads birth defect): 6 people, 46.15%
Pulmonary Artery Atresia (lungs artery absent): 1 person, 7.69%
Hair Loss: 1 person, 7.69%
Growth Hormone Deficiency: 1 person, 7.69%
General Symptom: 1 person, 7.69%
Device Failure: 1 person, 7.69%

What are the existing conditions these people have? *

Drug Exposure During Pregnancy: 3 people, 23.08%

* Approximation only. Some reports may have incomplete information.

Do you take Tysabri and have Foetal malformation?

- Check whether Foetal malformation is associated with a drug or a condition
- Predict drug outcomes for up to one year with AI
- Get an AI agent to monitor your drugs continuously

Related studies:

Effectiveness of, long term effects of, and alternative drugs to Tysabri:

Tysabri (221,369 reports)

Browse all side effects of Tysabri:

a b c d e f g h i j k l m n o p q r s t u v w x y z

Browse all the drugs that are associated with Foetal malformation:

Foetal malformation (76 drugs)

Browse all the conditions that are associated with Foetal malformation:

Foetal malformation (114 conditions)

How the study uses the data?

The study uses data from the FDA. It is based on natalizumab (the active ingredients of Tysabri) and Tysabri (the brand name). Other drugs that have the same active ingredients (e.g. generic drugs) are not considered. Dosage of drugs is not considered in the study.

How to use the study?

DO NOT STOP MEDICATIONS without first consulting your doctor. If there are any serious or long term adverse effects discovered in the study, discuss the study with your doctor to ensure that proper medication management will be in place if applicable.

Who is eHealthMe?

With medical big data and proven AI/ML algorithms, eHealthMe provides a platform for everyone to run phase IV clinical trials. We study millions of patients and 5,000 more each day. Results of our real-world drug study have been referenced on 800+ peer-reviewed medical publications, including The Lancet, Mayo Clinic Proceedings, and Nature. Our analysis results are available to researchers, health care professionals, patients (testimonials), and software developers (open API).

WARNING, DISCLAIMER, USE FOR PUBLICATION

WARNING: Please DO NOT STOP MEDICATIONS without first consulting a physician since doing so could be hazardous to your health.

DISCLAIMER: All material available on eHealthMe.com is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a qualified healthcare provider. All information is observation-only. Our phase IV clinical studies alone cannot establish cause-effect relationship. Different individuals may respond to medication in different ways. Every effort has been made to ensure that all information is accurate, up-to-date, and complete, but no guarantee is made to that effect. The use of the eHealthMe site and its content is at your own risk.

If you use this eHealthMe study on publication, please acknowledge it with a citation: study title, URL, accessed date.