The IT glitch has led to women scheduled for mammograms being sent home with a new appointment. There are also longer waiting times for samples, Södermanlands Nyheter.
However, the majority of healthcare can be carried out as normal thanks to backup systems, Region Sörmland's communications director Maria Karlsson tells the newspaper. There is nothing to indicate an attack from outside.
The IT disruption occurred on Wednesday morning, and 1177 says the region has gone into emergency mode.
"Among other things, the region's websites are affected. It may also make it more difficult than usual to get in touch with healthcare," 1177 writes on its website.
