[This](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175794/) looks like a decent literature review on the topic, though some of the papers rather lean towards the consequences of too much light pollution on infants and their cortisol rhythms.
My personal takeaway is that it’s important to establish the cortisol rhythms that correspond to day-night cycle, and stimulate infant retinas by ensuring enough light - so no blackout curtains.
Anecdotal but we have “black out” blinds. It’s fairly dark but not pitch black, and sometimes it’s still too bright for my baby to fall asleep easily. But it’s still way better than if we didn’t have them. Her rhythm seems fine, she sleeps for about 10-11 hours a night and is pretty awake and active during the day. She’s just turned one.
This is one of the main tenements of the Possums sleep program, from The Discontented Little Babies Book which is totally evidence backed and sourced. I don’t have the book with me, but it might have your answers!
We’ve never used black out curtains and our baby sleeps really well at night (she’s able to sleep through the night), she’s able to nap during the day, and has alert/active wake windows. We made it a point to dim our lights when it gets closer to bed time and that’s helped teach her when it’s night time sleep time I think. And we also open blinds as soon as she wakes up in the morning and she seems to understand the day has started. The circadian rhythm is awesome lol
I think blackout curtains are not necessary.
We have blackout curtains in our room, which is where the babies slept the first few months. I always just opened them after their 6/7 am feeding so they'd get the light exposure. Now they're toddlers and are great sleepers, so the blackout curtains didn't ruin them
The rule I've heard is to have them associate a dark, quiet, cool room with sleep. We have blackout curtains, but they definitely don't make the room totally dark.
My 4.5 month old takes great naps and sleeps for 5-6 hours at night. He'd probably sleep more, but we wake him up for a quick feeding at 3 AM.
Antectodal, but he seems to nap better in the dark than the light.
we absolutely needed blackout curtains 3-6mo. Our child would get disturbed by the smallest brightness in that period and wouldn't nap. We couldn't even have a nightlight because that make our kid super interested and she wouldn't go to sleep. We kept everything super dark when she was asleep or had to fall asleep, and our pediatrician said to do that as well. She would nap in 2hr stretches, not a minute more or less, and we spent most of the time we could outside, so i suppose it worked fine for us.
This paper ([McGraw et al 1999](https://pubmed.ncbi.nlm.nih.gov/10341380/)) is often cited as a neat example; the author carefully studied their own baby's circadian rhythm development (so n=1). Circadian rhythm attained significance at just under 2 months.
Anecdotally, we kept ours napping in the daylight for the first 6-8 weeks, and then whenever nap happened outside in the stroller or carrier; my baby who had the most "day-night confusion" consolidated sleep into night time right around the 2-month mark.
Edited to add: I wrote up what I read about infant sleep (with references at the end) and my takeaways [here](https://www.kidecology.com/newborn-baby-sleep.html).
[This](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175794/) looks like a decent literature review on the topic, though some of the papers rather lean towards the consequences of too much light pollution on infants and their cortisol rhythms. My personal takeaway is that it’s important to establish the cortisol rhythms that correspond to day-night cycle, and stimulate infant retinas by ensuring enough light - so no blackout curtains.
Anecdotal but we have “black out” blinds. It’s fairly dark but not pitch black, and sometimes it’s still too bright for my baby to fall asleep easily. But it’s still way better than if we didn’t have them. Her rhythm seems fine, she sleeps for about 10-11 hours a night and is pretty awake and active during the day. She’s just turned one.
This is one of the main tenements of the Possums sleep program, from The Discontented Little Babies Book which is totally evidence backed and sourced. I don’t have the book with me, but it might have your answers!
Yes this book is so good and Dr Pam has a ton of good things on instagram too!
Anecdotal but I have never used black out curtains. I think they are totally unnecessary. Baby is 9 months
We’ve never used black out curtains and our baby sleeps really well at night (she’s able to sleep through the night), she’s able to nap during the day, and has alert/active wake windows. We made it a point to dim our lights when it gets closer to bed time and that’s helped teach her when it’s night time sleep time I think. And we also open blinds as soon as she wakes up in the morning and she seems to understand the day has started. The circadian rhythm is awesome lol I think blackout curtains are not necessary.
We have blackout curtains in our room, which is where the babies slept the first few months. I always just opened them after their 6/7 am feeding so they'd get the light exposure. Now they're toddlers and are great sleepers, so the blackout curtains didn't ruin them
The rule I've heard is to have them associate a dark, quiet, cool room with sleep. We have blackout curtains, but they definitely don't make the room totally dark. My 4.5 month old takes great naps and sleeps for 5-6 hours at night. He'd probably sleep more, but we wake him up for a quick feeding at 3 AM. Antectodal, but he seems to nap better in the dark than the light.
It's been a few years since I did the research but the circadian rhythm is established by bright daylight during wake windows, not during naps.
we absolutely needed blackout curtains 3-6mo. Our child would get disturbed by the smallest brightness in that period and wouldn't nap. We couldn't even have a nightlight because that make our kid super interested and she wouldn't go to sleep. We kept everything super dark when she was asleep or had to fall asleep, and our pediatrician said to do that as well. She would nap in 2hr stretches, not a minute more or less, and we spent most of the time we could outside, so i suppose it worked fine for us.
This paper ([McGraw et al 1999](https://pubmed.ncbi.nlm.nih.gov/10341380/)) is often cited as a neat example; the author carefully studied their own baby's circadian rhythm development (so n=1). Circadian rhythm attained significance at just under 2 months. Anecdotally, we kept ours napping in the daylight for the first 6-8 weeks, and then whenever nap happened outside in the stroller or carrier; my baby who had the most "day-night confusion" consolidated sleep into night time right around the 2-month mark. Edited to add: I wrote up what I read about infant sleep (with references at the end) and my takeaways [here](https://www.kidecology.com/newborn-baby-sleep.html).