The Fussy Breastfed Baby

After a few weeks or months, breastfeeding has often settled into an easy rhythm. But what if you’re still dealing with a fussy breastfed baby or breastfeeding feels a struggle? Assuming any illness has been ruled out by your baby’s doctor, contacting an IBCLC lactation consultant can help brainstorm why your baby seems unsettled at the breast at any age or stage. There are many possible reasons—from your baby having a sensitive personality or being easily distracted by the world around him, to being hungry and just needing more breast milk. Cows’ milk allergyreflux or temporary lactose intolerance could also be involved in unsettled behaviour as could sensory processing issues or high muscle tone. This article reviews ten common causes of fussy, restless behaviour in a breastfed baby.

#1 Fussy personality

Sometimes what may seem like fussy or sensitive behaviour is normal baby behaviour. For example it is normal for a newborn baby to protest when they are put down; they love to be held and feel safest next to an adult body. It’s normal for newborn babies to feed very frequently, they are doubling their weight in a matter of months! It’s normal for an older baby to go through a phase of hating to be strapped in a car seat. The Womanly Art of Breastfeeding has several useful chapters on ages and stages which explain the normal behaviour of a breastfed baby as he grows. For example in the chapter “Six Weeks to Four Months: Hitting Your Stride” we are reminded that babies are individuals and sometimes being quite intense is a character trait:

Maybe you’ve got a sparkler – an intense, sensitive baby who needs input, input, input! His only settings are high and off. That’s the downside. The upside is how truly bright and curious he is likely to become. You’ll work hard as a mother to this baby. Look for other mothers of sparklers, to share notes with. Keep your sense of humour and try not to compare your busy days with those of your placid-baby friends. And keep your little sparkler close to you – your presence and touch will often go a long way toward calming him.

Fussy baby at four months

If your baby has been breastfeeding well for several months but then becomes a fussy baby at four months (or five or six or older!) it can be puzzling to find a reason for the change. Around this age is a common time for babies to refuse some breastfeeds and become easily distracted with noises, activities, new surroundings and siblings—particularly during the day time. The Womanly Art of Breastfeeding calls this The Four-Month Fussies. It’s a stage that will soon pass but you may need to remind your busy baby to breastfeed in the day and it may help to cut down on distractions at feed times such as closing the curtains to lower the lighting or putting subtitles on the television to reduce background noise.

baby on tummy in a cute hat

#2 Fussy breastfed baby, hungry baby?

A restless baby who constantly feeds or has trouble sleeping may not be getting enough breast milk especially if these behaviours are accompanied by poor weight gain. In Dr. Jack Newman’s Guide to Breastfeeding the authors believe that the most common cause of fussiness at the breast is when a baby is frustrated with slow milk flow resulting in hungry babies who fuss. They add that a tendency for mothers to feed by the clock instead of on demand can have the same result; a hungry baby. Their reasons for frustrated behaviour are listed in the following excerpt:

Pulling at the breast—slow milk flow

Babies pull at the breast, pull off the breast, fuss or cry at the breast and get angry for several reasons:

  1. The flow is too slow for them (this is the most common reason).
  2. The flow is too rapid for them. In this case the baby may actually choke, cough or sputter at the breast as well. However, if the flow is too slow it can also cause choking.
  3. The baby is full but wants to continue to suck, and the milk is flowing faster than he wants.
  4. The baby is reacting to something in the milk (i.e., something the mother has eaten or drunk).
  5. The baby is on nursing strike (this is discussed in the chapter “Late-Onset Decreased Milk Supply”).
  6. The baby is experiencing reflux. This “diagnosis” is made far too often.
  7. A combination of 1 and 2 (too fast early in the feeding, too slow later).

Jack Newman writes more about the possible reasons for a reduced milk supply after two to four months in his blog post Late Onset Decreased Milk Supply or Flow.

Get specialist help

Difficulty with controlling milk flow or a low milk supply can be due to a poor latch, poor positioning or poor tongue function. An IBCLC lactation consultant is the ideal specialist to help you identify which of these factors could be involved or help identify other causes for fussy behaviour. For self-help with slow flow of breast milk, or low milk supply have a look at How to Make More Breast Milk, Reasons for Low Milk Supply,  Is My Baby Getting Enough Milk? and What is Breast Compression?

#3 Bottle preference or nipple confusion

If a baby has started to have quite a few bottles as replacement feeds whether with expressed breast milk or formula, some babies can seem to start to fuss at or turn away from the breast in preference for the bottle. This is sometimes called bottle preference or nipple confusion. This is more likely to happen if a baby associates breastfeeding with frustration and slow milk flow but finds the bottle more rewarding. Or if a baby has a lot of bottles before they have got the hang of breastfeeding. If your baby is having more and more bottles and is starting to seem grumpy or unsettled at the breast, options to try include:

#4 Allergies as a cause of fussy behaviour

Babies who are allergic to something from their mothers’ diet passing into breast milk may appear unhappy at the breast—they might pull off once milk starts to flow because it hurts their inflamed oesophagus (eosinophilic oesophagitis) or gives them tummy ache. They may prefer to breastfeed in unusual positions and may be very tense and seem to clamp down or bite the breast causing pain and sore nipples1. They may have symptoms of reflux (#6) and/or tend to have very runny, copious and often green dirty nappies with symptoms of  lactose overload (#7). Allergy is thought to be a cause of infant colic (unexplained crying). Author Maureen Minchin describes a characteristic set of allergy-related fussy behaviours including disturbed sleep, erratic and persistent crying:

  • [Babies] who are either hyperactive before [in the womb], and persistently miserable after birth, or
  • [Babies] who start screaming in the second or third week of life, and
  • [Babies] who give many indications of gut discomfort
  • [Babies] who progressively develop other minor symptoms, like night sweats, cradle cap, or patches of rough skin
  • [Babies] who do not respond more than briefly to mothercraft skills

See Milk Allergy in Babies for an in depth discussion of dairy or other allergies in breastfed babies.

#5 Fussing with a fast let-down or too much milk

Some babies may find it difficult to cope with a very fast flow of milk causing them to cough, choke and constantly come on and off the breast. Babies have to coordinate sucking, swallowing and breathing during breastfeeding and, when the flow of milk is very fast, they may find feeding quite stressful causing them to restless and wriggly and keep releasing the breast. Fast flow can also accompany having “too much milk” which can also be a cause of unsettled behaviour or cause a temporary lactose overload with signs of discomfort and fussing (see #7 below). Babies who are getting a lot of milk quickly may also spit up frequently (#6). For more information see Oversupply of Breast Milk and What is a Fast Let-Down?

#6 Reflux and fussing

Spitting up some breast milk after a feed is quite normal baby behaviour and most babies are “happy spitters”. However if your baby has reflux and is very fractious and miserable—see Reflux in Newborns for more information. Reflux can be connected to allergy (#4 above) and too much milk (see #5).

Spitting up is a normal event for babies and doesn’t usually cause them a problem although more severe forms are possible e.g. GORD or GERD [gastroesophageal reflux disease]. Certain underlying causes such as allergy or oversupply can make reflux worse. Working with an IBCLC lactation consultant alongside your health professional can help find ways to reduce reflux or identify other possible reasons for an otherwise healthy breastfed baby to be miserable and fussy.

#7 Lactose overload

Lactose is the main sugar in breast milk. If a baby gets too much lactose too quickly (e.g. when there is “too much milk” see #5 above) or if anything prevents lactose being digested properly in the intestines it can cause a temporary lactose overload. An overload of lactose might cause several symptoms that can make a baby miserable such as wind, tummy ache and frothy copious green poop. It can be caused by and associated with cows’ milk allergy (#4 above) and may be one explanation for infant colic. For more information and how to resolve it see Lactose Intolerance in Babies.

#8 Sensory processing or high muscle tone

Some babies may have sensory processing issues, or high muscle tone that may contribute to intense and unsettled behaviour. Reading the linked articles may help to discover whether any of these could be an issue for your baby and what to do.

#9 Not enough physical contact

Sensory deprivation or lack of physical contact can cause a baby to be fractious. Jack Newman describes this as the common fear of “spoiling” a baby and he calls it the English Nanny Approach;

Babies cry for many reasons—it is the only way they have to communicate their needs. Many people believe that if you pick up or otherwise respond to a baby who cries, he will cry more and more; if you ignore his cries, he’ll stop. But research has shown just the opposite. The babies who are responded to most quickly and consistently cry less by the time they are a year old. Even more importantly, they tend to talk earlier and make more efforts to communicate, apparently because they have learned they will be listened to.

For those babies who crave physical contact, carrying them in a sling and accepting they need to be with you much of the time can help to meet their need for closeness. In a short time in the future they will not want to be held close or even hold your hand, enjoy it while you can! For some babies the opposite—over stimulation—can create unhappy behaviour.

#10 Other causes of fussy behaviour

Other ideas that may explain unhappy or restless behaviour could include minor dehydration (let your baby breastfeed frequently to quench his thirst), baby being too hot, too cold, being smoked over, wearing an overly tight nappy, having sore skin from an allergy, having sore gums from teething or thrush or being poorly e.g. having an ear infection2.


Some mothers may notice a connection between their baby’s behaviour and certain supplements or medications they take themselves or their baby takes. Fenugreek can affect some babies if the mother takes medicinal doses for her milk supply. And vitamins or iron supplements can affect some babies and cause discomfort 3.


Some babies could be fussy if they have had a reaction to a recent vaccination. Parents can access patient information leaflets listing side effects for vaccines in the UK from the NHS Childhood Vaccines Timeline.

My older baby is still fussy!

Some of the ideas above might still be useful to problem solve the reasons for a fussy older baby, or you may enjoy reading The Fussy Baby Book by Dr William Sears which covers birth to five years. If the fussing is happening particularly at night you may find Baby Waking Up At Night or Sweet Sleep: Nighttime and Naptime Strategies for the Breastfeeding Family helpful.


There are lots of reasons why a breastfed baby might sometimes seem unhappy or fussy such as being hungry, having allergies, sensory processing issues or lactose overload and more. Checking with your doctor will rule out a medical cause for your baby’s unsettled behaviour and the best way to rule out any breastfeeding related reason is to contact a breastfeeding specialist to help you.

* Extracts reproduced by permission from Pinter & Martin.