After the deaths of three babies in a little more than a year, Dakota County is preparing a wake-up campaign to motivate home child-care providers to put infants down to sleep on their backs.

The awareness campaign will start in April with postcards mailed to all 793 licensed homes in the county. The cards will feature a picture of a baby coffin.

The dramatic image is intended to drive home the seriousness of taking a risk with sleep safety and what can happen to the infant — and providers — if they do not put babies safely on their back to sleep, said Gail Plewacki, communications director for the county.

The stated goal is to “end infant deaths from unsafe sleeping positions in licensed child-care homes and bolster parents’ knowledge about the conditions and practices of their children’s care.’’

Infants ages 2 months to 4 months are at greatest risk because their muscles are not strong enough to turn their bodies or heads to bring in oxygen. They can die breathing their own exhalations if left face down on blankets or other soft surfaces.

Statistics show that the majority of infant deaths nationwide involve unsafe sleep practices.

The safest way for infants to sleep is on their back on a firm mattress with a form-fitting sheet, in a crib that is cleared of soft objects and loose bedding, county Social Services Director Joan Granger-Kopesky advises.

Because all three infants who died were in day care homes that were licensed by the county and where the caregiver had received training, the social services staff agonized over “what’s it going to take” to stop the deaths, she said.

They searched for something more they could do to get the message across.

Caregivers may not fully understand “the risk they are taking with each single sleep incident,” Granger-Kopesky said.

Some hold to the idea that they put their own children on their stomachs to sleep.

The postcards will invite the day-care providers to training on the county’s website and in group sessions.

The training will include a video interview with parents whose child died as a result of unsafe sleep practices at day care.

“They will talk about how hard that was,” Plewacki said.

Another part of the campaign is the distribution of safe sleep posters intended to be put up in day-care sleeping quarters.

The motivational effort will end in the fall with an article aimed at parents in the county newsletter.

Parents are a target of the campaign, too, because they may have limited information about their child’s care, Granger-Kopesky said.