At birth, babies with congenital myotonic dystrophy usually do not have muscle stiffness, but are usually very floppy due to delayed muscle development. Their feet might be deformed, they may not be able to breathe or feed properly, and they may need treatment in an intensive care unit (ICU). Women with DM1 should ideally have their baby in a hospital that has a neonatal ICU. The first few weeks are very critical for affected babies, but later on, the outcome is often better than was initially feared.
As they grow, children with congenital myotonic dystrophy might not learn to sit, walk and talk as quickly as other children and they might have facial weakness. They may have learning difficulties, with a short attention span and poor motivation, and tire easily. Their muscles seem to be less affected in childhood than might be expected from their weakness at birth. Some anaesthetics and sedatives are dangerous for children with congenital myotonic dystrophy, so you should always tell the doctors about it.