Couples having marital difficulties may have infants who are losing sleep, according to a new study, and that may have a continuing impact on the children.

Specifically, researchers found that marital instability when the child was 9 months old was related to child sleep problems at 18 months, including difficulties falling asleep and staying asleep, according to Anne Mannering, an Oregon State University faculty member in the Department of Human Development and Family Sciences.

"If sleep problems persist, this can correlate with problems in school, inattention, and behavioral issues," Mannering said. "Parents should be aware that stress in the marriage can potentially impact their child even at a very young age."

The findings of the research, which was funded by the National Institutes of Health, appear in the journal Child Development. Mannering was at the Oregon Social Learning Center when she and her collaborators conducted the research.

According to Mannering, this is the first study done on the link between marital issues and infant sleep that unambiguously eliminated the role of shared genes between parents and children. Researchers interviewed more than 350 families with adopted infants in order to eliminate the possibility that these shared genes influence the relationship between marital instability and child sleep problems.

"Our findings suggest that the association between marital instability and children’s subsequent sleep problems emerges earlier in development than has been demonstrated previously," she said.