First of all, this is not a breast versus formula debate. Really and truly. If you've checked me out you'll know I'm a lactation consultant as well..... I'm also a parent advocate, a child centred health professional, a fellow mum and a big fan of babies. Breast, bottle, whatever is the right thing for the family.
What makes me sad is when breastfeeding is actually going really well, but mothers think that giving formula will solve their sleep issues, so begin to wean from breastfeeding only to find that it often makes very little difference. I've known many breastfed babies who sleep 5,8,10, or 12 hours a night from just a few weeks, and I've know many formula fed babies who are up every 2 hours round the clock wanting to be fed. Don't believe the stereotypes!
Ok, so some facts:
1) Formula is modified cows milk, unless it specifically says otherwise. The cows milk has too much protein, so the first thing that happens is that it is watered down, then has to have fat and carbohydrate added so that the proportions resemble human breast milk. Otherwise babies would be sick, or even die from too much protein.
2) Formula has the same number of calories per millilitre as an average sample of breast milk, so it is not more 'fattening', 'rich' or 'nutritious' than breast milk. The protein is cows milk based so it is a little harder to digest, meaning that in large studies, babies fed formula on average sleep about 30 minutes longer between feeds than breast fed babies. Yep, 30 minutes. Not very significant really....
3) Babies in utero swallow amniotic fluid whenever they feel like it. Once born, they have to 'ask' for feeds. Babies have an innate need to suckle, and biologically speaking, this need is met by breastfeeding frequently. This is why bottle fed babies tend to use dummies/pacifiers more than breastfed babies - because in general bottle feeds are faster than breast feeds, so breast fed babies have more of their suckling needs met on the breast and don't therefore need a dummy as frequently.
4) Breastfeeding is about more than just food. It is also immunology, warmth, cuddles, comfort, calming, connecting and relating. We all have things we do for comfort during times of stress, excitement, celebration, loneliness, commiseration, fear or joy. Eating and drinking is one of those things we do at all of those times, not just when we are hungry or thirsty. Babies are no different!
5) You cannot over-feed a breastfed baby. Your milk supply will adjust so that you baby will get roughly the same amount every day from about 1-6 months (yes, I didn't mis-type! It's a little known fact that whilst formula fed babies keep needing more and more milk as they get bigger and older, breastfed babies drink a pretty consistent volume all the way from 1-6 months - cool huh?)
So, that brings me on to my point - that breast and formula fed babies are probably not very different. What differs is the parental response.
What I mean, is that because it is possible to over-feed a formula fed baby, most people keep track of how much their baby is getting, and then begin to organise feeds so that the majority of their baby's milk intake is during more convenient hours (obviously this is not possible or advisable with a very young baby who needs to feed frequently, whether breast or bottle fed). That doesn't mean that the baby won't wake in the night, but the parental response is different. Parents often try other strategies apart from feeding - such as rocking, holding, shushing or using a dummy/pacifier.
With a breastfed baby, the default position is to offer a breastfeed, because it often works to settle a fractious baby, and you can't overfeed so it ends up being a quick, reliable and risk-free solution. I'm not for a second suggesting that either response is right or wrong, but merely trying to point out why the night time often looks different as time goes on.
So, the bad news for breastfeeding families is that giving your baby formula in the hope that this will be what leads to better sleep is not a guaranteed solution, because your baby has developed a pattern of night waking based on their (very appropriate) need to connect with you overnight - it is not all about nutrition. Giving them more food will usually not make any difference at all. It's better to work on very gently and slowly disassociating feeding from sleeping if it's beginning to bother you.
And for the formula feeding or expressed milk bottle feeding parents out there - don't be disheartened by your baby's night waking! Giving them more milk is unlikely to help, unless they are not gaining weight as expected. Again, it would be very easy if babies only woke at night due to hunger, but they wake for numerous reasons - not always easy to guess reasons either! Carry on holding, rocking, or doing whatever you need to until you feel it's a problem, then very slowly wean your little one off their dependence on whatever it is they need to go to sleep. See my earlier blog post on self-soothing (myth that it is!) for more info!
I hope that reassures. Rock on mamas, you're doing great!