Unlike asylum seekers or paperless migrants from outside the EU, European migrants must have a European health insurance card to qualify for subsidized health care in Sweden.
Without that card, which gives the holder access to state-run health care during a temporary stay in any of the 28 EU countries, a person's access is cut off.
Ulrika Falk works at Gothenburg's rescue mission and told Swedish Radio the problem is common.
"The majority of those we meet belong to one of Europe's largest minority (Roma), and don't have access to health insurance in their own homeland. So they have no health insurance card with them," she says.
One recent example involved a pregnant woman in Härnösand municipality who was denied an ultrasound, despite concerns that something was wrong with the baby. She later had to undergo an emergency Cesarean where the child died.