The primary objectives of the study were to prospectively record and analyze birth defects and spontaneous fetal losses in women with multiple sclerosis (MS) exposed to Avonex within approximately 1 week of conception or during the first trimester of pregnancy, where the outcome of the pregnancy was unknown prospectively and to prospectively record and analyze pregnancy outcomes in an exploratory fashion of women with MS who stopped therapy, but who may have been exposed to Avonex with approximately 1 week of conception or during the first trimester of pregnancy.

Key Inclusion Criteria:

• Have been exposed to AVONEX within approximately 1 week of conception or during the first trimester of pregnancy.
• Provide sufficient information to determine that the pregnancy is prospectively registered (i.e., the outcome of pregnancy must be unknown prospectively).
• Provide verbal consent to participate in the Registry.
• Verbally provide contact information for herself, her HCP, and the infant's HCP (if applicable).

NOTE: Other protocol defined inclusion/exclusion criteria may apply.

Pregnant women with MS who were exposed to Avonex in the US