Pompe Pregnancy Sub-Registry is a study to follow pregnant women with Pompe disease, a rare genetic disorder where the body can't break down a sugar called glycogen, leading to muscle weakness. This study doesn't change treatment; it just observes how pregnancies progress. Whether or not the woman is getting specific treatments like ERT (Enzyme Replacement Therapy) with medicines such as alglucosidase alfa or avalglucosidase alfa, they can join. The study checks for any issues during pregnancy and how the baby grows. Participation is voluntary.

• The study involves both looking back at past pregnancies (retrospective) and watching current ones (prospective).
• You must be part of the Pompe Registry, be pregnant (or have been), and agree to participate with a signed consent.
• There are no specific reasons (exclusion criteria) that would prevent someone from joining this study.

No new treatments are tested, and participants continue with their usual medical care. This study helps doctors learn more about pregnancy in women with Pompe disease.