The purpose of this observational pregnancy safety study is to assess maternal, fetal, and infant outcomes after exposure to mavacamten at any time during pregnancy and/or breastfeeding.

Inclusion Criteria:

• Exposure to at least 1 dose of mavacamten at any time during pregnancy (from 4 months prior to conception to pregnancy outcome) and/or at any time during breastfeeding (up to 12 months of infant age or weaning, whichever comes first)
• At least 15 years of age or older at the time of enrollment
• Informed consent or institutional review board/ethics committee-approved waiver of informed consent

Exclusion Criteria:

- None

Individuals 15 years of age or older who are exposed to at least 1 dose of mavacamten at any time during pregnancy and/or breastfeeding.