12-Week Push: Here’s How Your Baby Is Developing

Developmental spurts in your baby are especially important, because little by little your offspring gets used to the world. Look forward to the next few weeks and see what new things your baby discovers from the third month. What challenges await you and your baby. Here you get all the important information.

Baby 12 Weeks: Growth Spurt

The 12-week growth spurt is the third growth spurt of a total of eight major developmental spurts in the first year of life. In this phase, your baby makes an important developmental leap. This developmental leap is very challenging for your offspring’s brain. He develops social behavior and begins to interact more with you. For example, when you smile at him, your baby smiles back

Your baby becomes curious and the environment becomes much more interesting. Your baby’s world changes. He starts to become more and more independent

Your nestling tries out new things and learns how to handle its own body. Whether it is examining the hands on the top and bottom, observing the movement of the feet or studying a face, the eyes, the mouth and the hair.

Remember, each child develops at his or her own pace. Your baby doesn’t have to be able to do everything right away. So don’t put pressure on yourself about your baby’s developmental order. Here you can learn how music can have a positive impact on baby’s development.

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Growth Spurt: What Are The Signs?

As your baby’s new abilities change the familiar world, the growth spurt will make your baby more restless and clingy. He will seek closeness with you and wants to be carried a lot. Most of the time, it will be nagging and crying. He may also have crying spells and become more jumpy.

In addition, it often happens that your baby sleeps less and less, because the sleep routine of your offspring is disturbed. The eating routine may also change, and your baby may have a large or small appetite. Sometimes there may be problems with breastfeeding or bottle feeding.

12-Week Push: What is Your Baby Learning?

From the third month onwards, your baby will have a 12-week push. Your baby’s head hardly needs any support. When he wants to see something, he turns his head immediately and fluently from side to side. Your offspring is more active and lively. They kick and turn in all directions. When changing diapers, for example, he lifts his bottom and puts his toes in his mouth. With the help of your hand, your baby can pull itself up to sit independently. If he sits leaning against you, he can sit upright without help

During the 12-week push, your baby clearly shows you that he is bored and needs variety. Your baby’s behavior shows what he likes or dislikes. He may behave or react differently with different people he meets


When your baby sees you, he or she laughs and kicks his or her arms and legs, clearly showing his or her joy. In this way, your baby begins to communicate with you and reacts to your behavior. It develops new sounds. In addition, your baby discovers screeching and crowing. He lets them fade from loud to soft or the other way around. In doing so, it tells whole stories with its new language. Your baby will also enjoy making bubbles with its spit.

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Motor Skills

In the prone position, your baby can already hold his head up 30 to 45 degrees. If you hold objects above your baby, his interest will be aroused. He or she starts to beat on it with his or her hands and can hold it independently for a short moment. Your baby thus reaches for objects consciously, purposefully and with both hands. For example, he can shake a rattle. Your baby learns to grasp during the 12-week push.


Your baby touches the Face, eyes, mouth and hair. It feels the hands and clothes and starts to nibble on them. Your baby starts to put everything in his mouth

You can encourage your baby’s development by stroking your baby’s hands with different materials. This is helpful because it allows your baby to feel that different things feel different. For example, you could use a feather, brush, wool, fur or fabric. Through these games, your baby can learn to touch and feel

How Long Does The 12-Week Growth Spurt Last?

Your baby’s growth spurts begin around the 5th week of life and end at the 56th week. This is based on the calculated date of birth and not the actual date of birth

In most cases, a growth spurt lasts about a week. This is usually followed by a relaxed phase in which your child tests the new abilities and you can recover.

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Challenges: What Are You and Baby Expecting?

Your baby needs physical closeness during the 12 week push. You will need a lot of patience during this time. This phase is not only exhausting for your 12-week-old baby, but also for you. You will be challenged because your offspring will demand more attention

Do not take on anything big during the 12-week push and concentrate on your child. Does your baby want to be comforted and soothed or does he prefer to be kept busy and entertained. During this time, a sling or baby carrier can be a real help. It strengthens the bond between you and your baby

What Should You Pay Attention To During The 12-Week Push?

You should pay attention to the following.

  • Avoid additional stress
  • Be calm and patient
  • Do not take on anything big
  • Be loving and understanding
  • Concentrate on your baby

Appointments: What Medical Exams Are Due at 12 Weeks’ Push?

U4 examination

From the 12th week, your baby should have the U4 examination. This is to check whether your baby has developed healthily and has already experienced the 12-week push

The German Association of Pediatricians and Adolescents (Berufsverband Kinder- und Jugendärzte e.V.) reminds you that you must make an appointment with your pediatrician by the 18th week of your baby’s life, otherwise the examination will be billed as an IGel service.

The Federal Center for health education gives an overview of what is checked by the pediatrician during the examination is checked. Several points play an important role here

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The pediatrician checks the age-appropriate physical and mental development of your baby. In addition, hearing and vision are examined and the fontanelle is checked so that the skull can continue to grow. You should be able to give the pediatrician information about your baby’s diet, digestion and accident prevention, if necessary. If your baby is a cry baby, you can also get help. Finally, possible repeat vaccinations will be discussed with the pediatrician


If you have your baby vaccinated according to the STIKO recommendation, pay attention to the vaccination dates. Before the appointment with the pediatrician, you should inform yourself about the vaccinations. Open questions should be answered by the pediatrician. If you are not sure about your baby’s vaccination, get more opinions.

Baby 12 Weeks Old: Size, Weight and Clothing Size

How big and heavy your baby can be on average at 12 weeks and which clothing size is the right one, you can find in the size chart.

Girls Boys
Size 52 to 66 cm 52 till 66 cm
Weight about 5.800 g around 6,400 g
Increase 110 to 330 g 110 till 330 g
Clothes/ Romper Size 62, possibly also 68 Size 62, possibly also 68
Caps Size 37 – 39 Size 37 – 39
Socks Size 15 – 17 Size 15 -1 7

Please note: Here are average values! They may vary from child to child because every child develops differently.

Look Forward To New Things

The 12-week push is not about your baby growing in size, but rather about your baby’s brain growing by leaps and bounds

This phase can be a real challenge, but it also fascinates you. Look forward to the new development of your offspring and avoid unnecessary stress. The calmer and more relaxed you are, the calmer and happier your baby can be

Even if it gets stressful sometimes, try to stay calm and patient. Observe and enjoy the time with your baby. Enjoy new events. Keep them as a souvenir with a photo album or a development calendar, because this time will not come back




The best products for you and your baby.

Baby monitor

With a baby monitor, you can use your time flexibly, sleep peacefully at night and still know at all times that your baby is doing well.

Nursing pillow

A good breastfeeding pillow has several advantages, because it helps you not only to breastfeed, but also to fall asleep and is also suitable as a nest.

Diaper bags

A diaper bag offers you a lot of storage space, so that you have everything you need for your baby on the go - from the changing pad to the bottle.


A pucksack gives your baby the feeling of security, like in the womb, and thus supports a peaceful and restful sleep.

Bicycle trailer

Bicycle trailers can be used in combination with a baby seat shortly after birth. They are not only safer than child seats but also more comfortable.


A playpen can be very practical in everyday life! Which model is suitable for your needs, you can read in my guide.

Baby bed

The first bed accompanies your child for years. Fortunately, there are beds that grow with your child. I have made for you on the search for the best baby beds.


A stroller is a worthwhile purchase. But there are the most diverse models on the market. Find out which is the right one.

Radiant heater

Radiant heaters provide your child with the necessary warmth when changing diapers or after bathing.

Extra bed

Side beds are very practical and offer both mother and baby a lot of advantages, because for babies, especially in the first months of life, it is reassuring to be able to sleep next to their parents.

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