Does improving infant sleep also reduce maternal depression symptoms?
Sleep, postpartum mental health, & trying to improve both
Ask any new parent whether or not sleep is good for them, and they will probably stare blankly at you with their sleep-deprived eyes, or scream, or laugh in your face at the cruelty that you would bring up sleep in the first place. Ask any infant whether or not sleep is good for them, and they will probably just start crying, or say nothing, because they are just a stupid baby.
We don’t need science to tell us that sleep is important for our mental health, but it exists anyway1. To put it bluntly: We feel good when we get enough sleep, and we feel bad when we don’t. Sleep disruptions are core features of many mental health concerns, such as major depressive disorder, bipolar disorder, and ADHD. As you can imagine, being the parent to an infant who keeps you awake all night, especially if you are experiencing mental health concerns, has its consequences.
[A quick aside: The majority of research on postpartum mental health is on cisgender birth mothers. There’s a lot to say about this and I hope to say more in the future. I also hope to be as inclusive as I can about the research I discuss. Please know that if you are a parent who does not fit into this category, your mental health matters, too.]
Postpartum sleep difficulties (usually defined as not getting enough sleep and/or constantly interrupted sleep) appear to be directly related to an increased risk of developing postpartum depression in mothers. Sleep difficulties are also associated with an increase in suicidal thoughts in moms experiencing postpartum depression. Mothers/Parents who identify as women often carry the majority of the infant caregiving burden, and this is particularly true for overnight caregiving. So it makes sense that sleep disruptions in an infant would have the most consequences for mom. One interesting study found that how well mom slept affected not just mom’s depression symptoms, but dad’s symptoms, too: Maternal sleep quality at six months postpartum predicted depression symptoms in both mom and dad 12 months after the baby was born. In other words, if mom was not getting enough sleep six months after the baby was born, both mom and dad dealt with mental health consequences six months later.
So what can we do about this? Based on my research on infant stress and sleep training, I was curious whether interventions focused on improving infant sleep can also help reduce postpartum depression symptoms, too.
The answer is: Maybe! Kempler and colleagues2 conducted a meta-analysis in 2016 that reviewed nine randomized controlled trials that examined infant sleep interventions. Rather than just relying on the findings from a single study, a meta-analysis is a statistical method that allows us to combine and compare the results from numerous studies on a specific topic. The studies included in this meta-analysis varied in the types of behavioral sleep interventions they examined - from interventions focused on teaching parents about infant sleep patterns, to helping parents implement specific sleep training strategies. Across these studies and different sleep interventions, infants in the sleep interventions slept more overnight than infants in the control groups. Importantly, five out of nine of these studies assessed postpartum depression symptoms in over a thousand mothers. Across these five studies, it appears that postpartum depression symptoms improved in moms who participated in the behavioral sleep interventions. This suggests that improving infant sleep is related to reducing postpartum depression symptoms.
As always, there are caveats to these findings. None of the studies included in this meta-analysis recruited a large number of mothers with clinical rates of depression, so it’s unclear whether these sleep interventions would help reduce symptoms in mothers with a diagnosable depressive disorder. The authors mention that two of the five studies they examined found that mothers with clinical rates of depression showed larger improvements in depression symptoms compared to moms who did not meet this threshold, suggesting that these interventions might benefit moms with diagnosable depression, but more research is necessary. Additionally, because the studies examined different sleep interventions, it’s not clear whether one type of sleep training method is better for improving depression symptoms in parents than another.
Interestingly, the sleep interventions studied in this meta-analysis did not appear to improve the number of times a baby woke up during the night, only the total amount of overnight sleep. While totally speculative, this suggests that maybe the total amount of infant nighttime sleep is more important for mom’s mood than how many times the baby wakes up during the night. Alternatively, maybe simply trying to change baby’s sleep for the better is enough to improve mom’s depression symptoms. In other words, for a family to choose to participate in an infant sleep intervention means that the family is taking the infant’s sleep seriously, which, in turn, might mean that they are taking mom’s sleep (and her mental health) seriously, too. I bet this is just as important in helping improve mom’s depression symptoms as anything else.
Sleep is important for postpartum mental health. Across five randomized controlled trials of different behavioral sleep interventions, infants slept more and maternal depression symptoms improved. More research is necessary to understand which types of sleep interventions help improve maternal mood the best, and whether or not these interventions help parents with diagnosable depressive disorders or other mental health concerns.
I still think it’s wild that we take for granted that sleep is important and necessary, even though the jury is still out on why human sleep in the first place!
Kempler, L., Sharpe, L., Miller, C. B., & Bartlett, D. J. (2016). Do psychosocial sleep interventions improve infant sleep or maternal mood in the postnatal period? A systematic review and meta-analysis of randomised controlled trials. Sleep Medicine Reviews, 29, 15-22. https://doi.org/10.1016/j.smrv.2015.08.002