It seems obvious, but sometimes that’s what it takes for us to pay attention: A new study from the University of Illinois shows consistently poor and insufficient sleep patterns make parents more lax and inconsistent in rules and discipline.

The team got 234 mothers to wear actigraphs, a wristwatch-like device that detects movement throughout the night to gauge soundless and interrupted sleep. For seven consecutive nights mothers wore the device to collect data on their sleep patterns, and also provided the study information about their race/ethnicity and socioeconomic status.

Their adolescent children were then asked to complete a questionnaire about what they thought of their mothers’ parenting. Behaviour was rated on a scale of likely to not likely. Example statements included, “Lets me off easy when I do something wrong,” “Can’t say no to anything I want,” or “Doesn’t check up to see whether I have done what she told me.”

The studies found that mothers who experienced better sleep patterns were less likely to be overly permissive, whereas mothers who frequently did not get sufficient sleep, or who took longer to fall asleep, showed more inconsistency and laxness in parenting. This was particularly true for women from disadvantaged socio-economical backgrounds.

“Short and disrupted sleep patterns are common among parents, especially parents of young children, and can affect their mental and physical health and daily functioning,” says Kelly Tu, an assistant professor in the department of human development and family studies at University of Illinois. “It may be that they’re [parents are] more irritable, experiencing impaired attention, or so over-tired that they are less consistent in their parenting. But on the plus side, we also find that mothers who are receiving adequate sleep are less likely to be permissive with their adolescents.”

Consistency is one of the hallmarks of parenting — a key component of most parenting tips — and a lack of it can lead to both perceived and actual behavioral problems in kids. This is true even in adolescence, when kids still need parental guidance in order to develop socially, emotionally and behaviorally. Indeed, Tu’s finding of a link between lax parenting and the likelihood of problematic and risky behavior in adolescents only builds on a large body of research that has reached similar conclusions.

The conclusions of the study emphasize the need for better self-care — and, perhaps, better resources and support for busy mothers (and fathers; there’s nothing to suggest this phenomenon is specific to women).

“Sleep is an easier point to intervene in terms of changes individuals can make–things like not drinking caffeine or exercising too close to bedtime, establishing a bedtime routine, and thinking about the sleep environment,” says Tu. “Parents may be thinking about these things when it comes to their children, but it’s just as important for parents to get enough sleep as it may impact their family interactions and children’s wellbeing.”

The takeaway? If you have to make an important decision as a parent, maybe sleep on it — soundly — first.