Breastfeeding Vs Formula: Feeding and the Impact on Infant Sleep


Sleep is essential to our daily life. As a new parent, you want to ensure that you and your infant are getting the best sleep possible. Friends might tell you that breastfeeding your baby will be the best way to ensure a peaceful night's sleep, while another person may suggest formula feeding for the best slumber. Couple this with other information around how much sleep a baby should get, and feeding techniques and protocols can seem overwhelming.

Research surrounding formula versus breastfeeding and the impact on sleep is conflicting. In the case of breast milk vs. formula, it appears that some studies support both positions. This can add to the confusion. However, most studies do say something similar about infants and sleep: no matter what you feed them, their sleep will improve as they grow and get older.

Breastmilk or Formula: Which is Better for Sleep?

There is a long-standing assumption that formula will promote longer sleep periods and less wakefulness during the night. Despite recommendations from the World Health Organization to breastfeed exclusively until a child is 6 months old (1), mothers in need of more sleep sometimes choose to introduce formula early. Is this rumor about formula true?

A study in 2017 found that three-month-old babies fed breast milk during the first few months of their life slept more during the night (2) than their formula-fed counterparts. However, this study also found that the exclusively breastfed babies had a harder time sleeping by age 6 months than the babies who were fed formula.

Another study in 2013 found that breastfed babies woke more often than formula-fed babies. However, they had fewer breathing issues and were able to fall asleep faster (3). Breast milk naturally contains melatonin, a hormone associated with sleep (4). Infants cannot produce this hormone on their own and rely on the secretion in breast milk to help regulate their circadian rhythms.

Formula does not typically include melatonin. Therefore, some studies suggest that the presence of melatonin in breast milk means that breastfeeding increases sleep quality by decreasing colic and crying spells (5) and helping the infant return to sleep quicker.

Infants are developing so quickly, and their sleep patterns reflect this. One study in 2015 showed that formula or breastmilk had little effect on the sleep/wake patterns (6) of babies over the age of 6 months. Both breastfed babies and formula babies showed a decrease in nighttime wakings as they aged past 6 months. Ultimately, one group did not outperform the other in terms of sleeping longer.

What about feeding my baby both formula and breastmilk?

Researches compared a group of hybrid-fed babies to babies only fed by breastmilk and only by formula and found that a hybrid feeding routine had little impact on overall wakefulness and sleep. Utilizing a hybrid feeding schedule does not seem to help your baby sleep through the night.

Should I feed my infant extra food before bedtime?

A common assumption is that topping off your baby’s last meal with rice cereal or another heavier food before bed will increase sleep. This belief appears to be untrue, as research suggests that feeding additional solid food to your child will not decrease wakefulness (7) during the night. Cereals or other foods should not be added to bottles for safety reasons.

It’s important to note that your baby’s stomach capacity is very small and therefore cannot hold a large volume of milk and that babies under the age of 4 months should be given no food other than breast milk or formula. While there is some evidence to suggest that formula takes longer to digest than breastmilk, your baby will still require frequent feedings due to the small size of their stomach, regardless of what option you chose.

While feeding your child more food before bed might reduce their hunger levels throughout the night, it doesn’t seem to impact their sleep patterns.

What else can I do to help my baby sleep?

There is often the belief that babies wake in the middle of the night only due to hunger. This, however, is not entirely true. Evening routines, sleep schedules, and other factors specific to you and your baby impact their sleep.

Successful nights require more than just a good feeding. Regardless of if you chose to feed your infant breastmilk or formula, you can help them sleep longer by:

  • Creating a sleep schedule and sticking to it
  • Keep the room dark and comfortable
  • Block out noise
  • Set a specific time to get up
  • Keep a sleep schedule to track sleep/wake patterns

How do I know which is right for my baby?

While the research is inconclusive, it shows that overall, formula and breastmilk do not drastically differ in how they impact infants' sleep/wake cycles. Research also shows that the common belief of “topping off” your baby with solid food before bed has little overall impact on the quantity of sleep.

Breast milk provides sleep-inducing hormones and appears to help with breathing and colic issues in infants. It is easier to digest, which may contribute to more frequent night wakings. On the other hand, formula is harder to digest and may help your baby sleep marginally longer. However, formula does not help your baby fall back asleep quickly as it does not contain sleep hormones.

The research does agree that infants will wake during the night regularly until about age 12 months regardless of what they are being fed. Studies show that maternal sleep patterns do not differ between breastfeeding or formula (8). As your baby ages, their sleep cycles will lengthen, allowing you to get better sleep yourself. Here are a few steps you can take to make the best decision for yourself:

  • Talk to your doctor about your sleep and feeding concerns. Mothers experience a drastic decrease in sleep quality (9) as well, and this can impact their overall health.
  • Talk to a trusted friend
  • Learn about infant sleep methods and how to implement them with your child


+ 9 Sources
  1. 1. Accessed on February 13, 2021.
  2. 2. Accessed on February 13, 2021.
  3. 3. Accessed on February 13, 2021.
  4. 4. Accessed on February 13, 2021.
  5. 5. Accessed on February 13, 2021.
  6. 6. Accessed on February 13, 2021.
  7. 7. Accessed on February 13, 2021.
  8. 8. Accessed on February 13, 2021.
  9. 9. Accessed on February 13, 2021.

Related Reading:

  • Crib Essentials: How to Prepare a Bed for Baby

    Creating a comfy, cozy sleep spot for your newborn is important, but so is putting your baby to sleep carefully. Certain types of bedding can raise the risk of Sudden…

  • How Much Sleep Do Babies Need?

    Babies are asleep for more than half of their first year of life. This time spent sleeping allows an infant's brain and nervous system to develop, preparing them for the years to come. We cover how much sleep your baby needs to promote healthy growth, why sleep is so crucial for infants and toddlers, and answers to the most frequently asked questions about infant sleep habits.

  • How to Get a Baby to Sleep Through the Night

    Parents of babies are often sleep-deprived due to their baby's night awakenings. Learn when your baby should sleep through the night and how to help them.