How babies develop in their 4th month

Appointments – What’s coming up in the 4th month?

U4: If the U4 did not take place in the third month of life, now is the time. Remember to bring the certificate your health insurer sent you in advance. This must be signed by the paediatrician after the examination so that you can return it to your health insurer or the relevant office.
Booster vaccination: The second six-in-one vaccination boosts the primary immunisation begun with the first dose. Even if your baby showed no side effects after the first vaccination, they may react to the second with fever, lethargy or diarrhoea – as a precaution you should have something to reduce fever at home.
Finding a babysitter: Although many parents initially find it difficult to leave their few‑months‑old baby with someone else, a short break from everyday life is worth it. If no grandparents or experienced friends are available, acquaintances may have a tip for a trustworthy babysitter, even if it is only for a few hours.

Important developmental milestones in the 4th month

Physical development: Your baby has roughly doubled their birth weight in the fourth month. Most babies no longer need to be fed so frequently because they take in larger amounts and stay full for longer.
Sleep: You may now sometimes find that your child sleeps six or seven hours at a stretch at night. It usually takes a while before this becomes the rule. Overall nights become a little calmer because your little one develops a regular sleep rhythm.
Muscles: Many babies can hold their head up well when lying on their tummy in the fourth month. When they prop themselves up on their arms their field of vision increases – at the same time they are exercising the muscles they will later need for crawling.
Laughing and "talking": Your baby now already shows quite clearly what they like and what they do not. They have learned to laugh out loud and even sometimes try to respond to simple sounds like "Buh" or "Bah" when they hear them.

How much should my child weigh at 4 months?

Physical development now progresses a little less rapidly than in the first months of life, so there are not very large changes in height and weight. Instead, motor development of your little one comes to the fore as they learn to control their body. In the fourth month your baby is about 62 to 64 centimetres long and weighs between 6,400 and 7,000 grams.