An electronics assembly destined for a medical device is not technically harder to build. What changes is everything around the build: what gets recorded, who may approve a change, and how far back you can trace a component when a question is asked three years later.
ISO 13485 is built around that record. Every lot is traceable to its date codes and suppliers, every process change carries documented justification and approval, and the device history file has to reconstruct exactly how a given unit was made. An EMS partner without that structure can still build the board, but the OEM inherits the burden of proving it.
Change control is where most programmes feel the difference first. A component substitution that would take an afternoon on a commercial build becomes a documented evaluation with its own approval path. That is not friction for its own sake; it is what makes the eventual submission defensible.
The practical advice is to have the conversation early. Bringing a contract manufacturer in during design, rather than after the layout is frozen, is what keeps traceability and validation requirements from turning into schedule risk.
