6 Reasons Why Your 6 Month Old Baby Is Suddenly Fussy All Of The Time?

Dealing with a fussy baby can be stressful for you and your baby. As parents, we want nothing more than to comfort our babies when they are crying and upset. What are some reasons for fussy behavior in a 6-month-old baby? 

Growth spurts, a change in diet, a change in sleep schedules, illness or allergies can all cause increased fussiness in your 6-month-old. 

Common Reasons Why Your 6 Month Old Baby Is So Fussy All Of The Sudden?

Below are some of the most common reasons why your 6-month-old has suddenly become so fussy.  

Growth Spurts

At 6 months old many babies will have a growth spurt. This can cause them pain and discomfort when their bodies, muscles, and bones stretch. These growth spurts may cause your 6-month-old to be hungrier more often. 

If they are experiencing growth spurts, you can comfort them by laughing, talking sweetly, and giving them baby massages, gently rubbing their arms and legs to help comfort their muscles as they grow. 

Moving to Solid Foods

Changing your baby’s diet to solid foods from formula or milk can cause digestive issues as they adjust to their new diet. These changes can cause constipation, rashes, and stomach aches. It can be quite the adjustment moving to the new diet and can cause an increase in their fussy behavior. 

Providing your baby with a balanced diet of fruits and vegetables will help alleviate some of the issues of constipation and gas that can accompany trying new foods. 

6 Month Old Baby Is Suddenly Fussy


As more solid foods are introduced they can trigger an allergic reaction in your 6-month-old. Be sure to follow a doctor or dietitian’s recommendation of when to introduce any new foods. If you notice diarrhea, congestion, hives, or difficulty breathing with your baby it could indicate a food allergy.  

If the symptoms do not improve you may need to seek emergency medical care to identify and treat an allergic reaction. If the symptoms are not serious, you should discuss them with your pediatrician to identify any allergies your baby may have. 


Teething can be a major reason babies become fussier at 6 months of age. When babies are teething they can be extra fussy. Signs your baby may be teething include drooling, swollen spots on the gums, and trying to chew on everything.  

If your child is teething there is a lot of parental advice that may work and may not. Massaging their gums, giving them something cold to suck on, or hard teething rings may bring them and you some relief.  

Ear infections

Ear infections can be a common source of fussiness in babies of any age. Pain from ear infections is worse when laying down, sucking, or chewing because it increases the pressure of the eardrum. This could cause them to be fussier during the night when it is time for bed.

Signs your baby may be suffering from an ear infection include pulling at their ear, fluid draining from their ear, balance issues, or trouble hearing. Ear infections can be treated with over-the-counter medication and a visit to your pediatrician if it does not clear up after a short time. 

Sleep Regression

At six months, your baby may experience sleep regression. They should switch from three small naps a day to two longer ones. The increased interaction at that age can make it more difficult for them to adjust to the new schedule. Nap times may require extra effort to calm them before setting them down to nap. 

If you see your baby showing signs that they are sleepy such as rubbing their eyes, yawning, or becoming fussy it is time to transition them to nap time. The more consistent this routine the faster they can adjust to their new schedule.  

Final Thoughts

When your 6 month old baby suddenly starts fussing and crying more than usual, it can be a confusing and frustrating situation for parents. Sudden fussy behavior in babies is usually caused by an underlying issue that needs to be addressed. Common causes of sudden fussiness in a 6 month old include teething, sleep regression, hunger or thirst, discomfort due to growing pains or changes in environment or routine.

The best way to handle sudden fussy behavior in your 6 month old is to look for the root cause of the problem and address it accordingly. If you think teething may be causing the fussiness, try giving the baby something cold such as a wet cloth or frozen vegetable baggie to chew on. If hunger seems like the culprit, try offering them more frequent feedings throughout the day.