The objective for establishing the Rebif® Pregnancy Registry is to collect prospective outcomes data on women in the United States and Canada who have been exposed to Rebif® during their pregnancies. The primary end point will be the rate of spontaneous abortions in exposed pregnancies. This rate will be compared with the rate of spontaneous abortions in patients with Multiple Sclerosis (MS) whose pregnancies were not exposed to any interferon-beta in a manner consistent with the FDA August 2002 Guidance for Industry: Establishing Pregnancy Exposure Registries

This study is a post-approval commitment to follow Rebif®-exposed pregnancies and compare them to non-Rebif® exposed pregnancies to evaluate rate of spontaneous abortion, fetal abnormality or pregnancy related health outcomes.

Inclusion Criteria:

• Rebif®-Exposed Group

For prospective follow-up, women in the United States and Canada shall be eligible for enrollment in the Rebif® Pregnancy Registry as subjects if:

• They are pregnant.
• They received Rebif® for treatment of Multiple Sclerosis (MS) within one week before or at any time after conception.
• The outcome of pregnancy has not been previously evaluated by any diagnostic method such as ultrasound. However, since ultrasound techniques are often used at early stages to confirm pregnancy, patients who have been evaluated by ultrasound for the purpose of confirming the pregnancy shall be eligible for enrollment in the Registry. The use of ultrasound and any inferences that could be made about the outcome of the patient's pregnancy will be reported on the case report form. Following enrollment in the Registry, diagnostic tests may be performed at any time during the pregnancy.
• They have not used Copaxone® for treatment of MS within the previous three months and have not been exposed to Novantrone®, Imuran®, Cytoxan®, Tysabri® or methotrexate at any time.

Patients who have been exposed to an investigational product or procedure within the previous year may be enrolled at the discretion of the Medical Director. The enrolling physician should contact Serono's authorized agent, a company called Registrat, at 866-997-3243 to request a review of each patient's situation.

Interferon-beta -Not Exposed Comparison Group

Women with MS who live in the United States or Canada will be eligible for the comparison group if:

• They are pregnant.
• The outcome of pregnancy has not been previously evaluated by any diagnostic method such as ultrasound. However, since ultrasound techniques are often used at early stages to confirm pregnancy, patients who have been evaluated by ultrasound for the purpose of confirming the pregnancy shall be eligible for enrollment in the Registry. The use of ultrasound and any inferences that could be made about the outcome of the patient's pregnancy will be reported on the case report form. Following enrollment in the Registry, diagnostic tests may be performed at any time during the pregnancy.
• They have not received any interferon-beta within 90 days of conception.
• They have not used Copaxone® for treatment of MS within the previous three months and have not been exposed to Novantrone®, Imuran®, Cytoxan®, Tysabri® or methotrexate at any time.

Patients who have been exposed to an investigational product or procedure within the previous year may be enrolled at the discretion of the Medical Director. The enrolling physician should contact Serono's authorized agent, a company called Registrat, at 866-997-3243 to request a review of each patient's situation.

Exclusion Criteria:

• Not Applicable

Pregnant MS patients

From study entry until pregnancy outcome. For the purposes of this Registry, the protocol captured as adverse events only unexpected pregnancy events.

These events included spontaneous abortion, stillbirth, elective abortion, anomalies diagnosed at birth, termination or the 28-day follow-up evaluation, labor/delivery complications, pre-eclampsia/eclampsia, premature labor/delivery, and "other" to be specified by the Investigator.

Despite a consistent and exhaustive expenditure of resources over 5 years only 36 subjects were enrolled into the Registry, a number which precludes meaningful statistical analysis of the potential risks of Rebif® during pregnancy.