From the moment your baby comes out of the womb, they are doing incredible things. The development process of an infant in their first few weeks of life is truly like any other, including their seemingly superhuman sense of smell. Yes, newborns recognize your scent within days of birth — but can newborns smell you when they sleep?
Though there are mixed reviews on whether or not it's a good thing that they can smell you when you sleep, the general consensus seems to be, yes, they can smell you when they sleep.
According to Parents, babies are "veteran sniffers" by the time they're born, because their olfactory senses are one of the first to mature in utero. In fact, they develop them by the end of the first trimester. Because the amniotic fluid adapts to the smell of everything you eat and drink, your baby comes out of the womb with a preference for those smells. But of all the smells your baby reacts to, it's the smell of you that newborns prefer over any other. Parenting noted that 3-day-old infants are able to distinguish their mother's milk from someone else's by smell alone. The U.S. Department of Women's Health says this is why babies turn toward you when they're hungry, because they can smell your unique scent, and they want what they've learned comes from that unique scent — food.
In the Baby Center community, moms reported that their babies didn't sleep as well if they were in the same room as mom, and that they often slept through the night when put down in their own room, or in a separate room from mom. And their pediatricians backed them up. According to Glade B. Curties and Judith Schuler, authors of Your Baby's First Year, Week By Week, infants rely on their sense of smell to recognize the scent of their mother's nipples. Your baby associates this smell with comfort, security, and of course, hunger. Though it might seem like there could be a correlation between the sense of smell and wanting to feed throughout the night, other research seems to negate the idea that a fussy baby could be losing sleep because of your scent. In fact, most research finds that mom's scent helps calm a baby down, and keep them sleeping through
Suzy Giordano and Lisa Abidin, authors of The Baby Sleep Solution, added that if your baby calms down when you're the one holding him or her, they're more likely to fall asleep faster when they can smell you — even if you're not in the same room. Giordano and Abidin recommend infusing your baby's pajamas or blanket with your scent to help ease them without having to be present all of the time. To infuse, sleep with the item of your baby's against your bare skin for two or three days, and the scent will transfer to the fabric. According to the Kids Health website, you want to make sure that you're only infusing items of your baby's clothing, and not providing them with clothing or blankets of your own, as items that are too large or bulky can endanger your infant while sleeping.