18 Week Old Baby: Development, Milestones & Care Tips

18 Week Old Baby – Development, Milestones & Care

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Dr. Arti Sharma (Paediatrician)
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Your baby is officially 18 weeks old, and you might have witnessed quite a few developments in him in the past months. While it may seem that he has turned 18 weeks so soon, you know well that’s not true! You have had sleepless nights and done everything possible to care for him and help him meet his milestones. By now, your little one must have discovered his feet and toes, and he will start rolling over any day now if he hasn’t already. By this stage, most babies ramp up their development even more and get a good idea of how to handle themselves. Learn everything you need to know about your 18-week-old baby’s development.

Your 18-Week-Old Baby’s Development

Your baby will continue to gain weight, but his weight gain will reduce slightly compared to the previous months. From now on, his emotional and mental development will start. That being said, many changes will still happen in the physical behaviour and motor coordination portions of his body. Having started rolling over already or being pretty much on the verge of doing that, your baby will now fall in love with the concept of movement and want to carry it out. Your baby may constantly wriggle if you hold him or wrap him, and at times, might bump his head on the floor or fall off the couch, and so on. If your baby has started rolling over, you need to take extra precautions to prevent the worst from happening.

[Also Read: 4 Months Old Baby Development]

Weight of 18 Week old Baby

The typical crown-heel length of a baby at 18 weeks, measuring from the head’s top to the heels, is about 8 1/3 inches (21.2 centimetres). The baby weighs nearly 8 ounces (222 grams) this week.

Your 18-Week-Old Baby’s Milestones

 An 18 week-old baby

  • By this week, your baby will find everything interesting and intriguing. He will even be intrigued by his body parts and discover his hands and legs. He will observe his fingers and toes, see how they move, and attempt to put them in his mouth. He will soon gather how to use them the best. This could mean he can put his legs on the crib bars and push himself to move around in that space. Don’t be surprised to see your baby in a weird position moments after you leave him there on his own.

  • Although wrapping your baby when he sleeps will help him prevent from doing any harm to himself, many recommend leaving your baby as is. This will allow him to move his limbs a lot more than before, which will then help him learn to walk.

  • By this time, your little one’s teeth will start preparing themselves by taking their positions under the gums and erupt slowly. If your baby has early teething tendencies, there is a high probability that the front teeth of the bottom gum might already be starting to show themselves near the surface, just about to cut it.

  • Your baby will now learn about his individuality and understand that his sounds will differ from yours. He will see your face in the mirror alongside his own and will learn things from you.

  • Slowly, he will start interacting with the familiar faces around him – he will also start trusting them. This also means that strangers might make him wary, and he may cry looking for you among strange faces. But the more time your baby spends with them, the more he will trust them.

  • His perception of space, depth, and coordination will greatly improve by this time. Fewer failures will meet his judgement in going for objects and grabbing them. Looking at multiple objects and following those with his eyes will start becoming a normal task for him.

  • His communication skills will develop a lot (as per his age, though) more as he will try to imitate the sounds you make and establish contact with you. This can escalate further as you repeat the sounds he makes but in a louder voice or a different tone. It acts as validation and encourages him to communicate more often. Using different objects to make sounds will also help in the same way.

[Also Read: 4 Months Old Baby Milestones]


Most mothers tend to start making their way to return to work or at least take some time off to catch up with work-related activities from home. This might necessitate feeding your baby via a bottle, especially if he has been feeding off your breast all this while. Many babies accept the bottle quickly since the increased flow and convenience work in their favour. Other babies might want breastmilk and may not accept the bottle readily.

One way to work this out is to keep a bottle by your side while breastfeeding your baby. You can introduce the bottle gradually. If you introduce it slowly and repeatedly, it will make your baby believe that the bottle is an extension of you and start drinking from it as well. Gradually, you can let your baby lie by your side and feed him using a bottle or ask somebody else to help you. Some babies reject a bottle but accept milk through a cup or so. If any other person is going to be taking care of the feeds in your absence, do make sure they have a proper understanding of how much feeding is necessary and an approximate schedule that your baby is used to.

If possible, pump the breastmilk and store it so that it can be given via bottle, and resort to giving the formula only if this isn’t a possibility. Your parents or relatives of the earlier generation might take care of your baby and find it appropriate to introduce solid foods since that was the norm in their times. It is important to make it clear to abstain from giving any solids. Your baby might show interest in wanting to taste something on seeing others have their food, but don’t start with solids yet. Your little one is still too young to be given solids. 

[Also Read: 4 Months Old Baby Food]


For an 18-week-old baby, sleep remains the most important aspect of his growth. Any distractions may disrupt his sleep and make him cranky. If others are taking care of him, do let them know of any techniques or any music that is beneficial in making him fall asleep quickly. Holding him for a while, cuddling him, or taking a small stroll in the pram and other such activities can make him fall asleep. There isn’t a particular need to wrap your baby up when he sleeps at this age. But you must ensure that there are no hard toys or objects on your baby’s bed while he sleeps or he might hold them in his sleep and get hurt.

[Also Read: 4 Months Old Baby Sleep]

Tips to Take Care of Your 18-week-old Baby

Here are some tips you should follow while caring for your 18-week-old baby.

  • You can introduce bottle feeding to him, but the transition should happen slowly and gradually; plus it should be comfortable for your little one.
  • Your little one will soon start rolling, so keep toys with sharp edges away from him. When your little one is asleep, ensure no hard toys are near him.
  • Try hanging playful objects above your baby to keep him occupied when he wakes up.

[Also Read: 4 Months Old Baby Care]

Tests and Vaccinations

The vaccines for PCV, diphtheria, Pertussis, Tetanus, Polio, Hepatitis B and Rotavirus are usually already administered until the baby has completed 4 months. If the vaccines have been given before, no vaccination is necessary now. If not, your doctor will assist you in developing the right schedule for them.

Games and Activities to Keep Your Baby Engaged

Your baby’s power to remember and recall will develop significantly in these weeks, and it is necessary to keep that progress going. As sounds are important, so is silence. By talking to him constantly, you can introduce the concept of being quiet by whispering or talking softly (or not talking for a while and just observing him). These little acts and games will help him recognize sounds better. The act of saying “shhh” and then talking gently to your child can be quite an experience for him. At the same time, you can make it fun for him by talking to your baby via a baby monitor. This can also be done by recording your voice on the phone and playing back the audio from another corner of the room. Just the presence of your voice will bring about a smile and recognition on his face.

[Also Read: 4 Months Old Baby Games and Activities]

When to Consult a Doctor

Babies are curious; by now, you must have figured that out! Your little one will be curious, too; he will be curious about himself and notice different things about him. But if your baby doesn’t seem interested or doesn’t register his presence, it is strange and should be checked with the doctor.

This could also be in the case of new toys and games. And if your baby doesn’t show any interest in interacting with others and seems lethargic, it could be because of some health-related issues. So you must take him to a paediatrician immediately.


1. How Far Can an 18-week Old See?

Your infant’s vision at this stage is developed to the point where they can perceive objects at a distance of approximately 8 to 12 inches. While their gaze might occasionally shift aimlessly and even cross paths, your baby is beginning to coordinate their eyes, allowing them to align their gaze and follow a moving object reliably.

2. Do Babies Have Growth Spurt at Week 18?

Rapid growth episodes are a natural component of a child’s developmental process. They will occur intermittently from infancy through physical maturity, typically between 16 to 20 for girls and 17 to 20 for boys.

Your baby’s mental and emotional development will be rapid at this stage and give him a personality in the future. You will also see other developments in him! Your baby’s progress can bring relief; you should feel proud of him. But if you feel your baby is not developing as his age, consult a doctor and get him checked!


1. Misirliyan. S. S; Boehning. A. P, Shah. M; Development Milestones; NIH; https://www.ncbi.nlm.nih.gov/books/NBK557518/; March 2023

2. Weight-for-age; WHO; https://www.who.int/tools/child-growth-standards/standards/weight-for-age

3. Data Table for Boys Length-for-age and Weight-for-age Charts; CDC; https://www.cdc.gov/growthcharts/who/boys_length_weight.htm

4. Baby’s physical development; Pathways.org;

5. Feeding Tips For Your Baby with CHD; Heart Attack and Stroke Symptoms; https://www.heart.org/en/health-topics/congenital-heart-defects/care-and-treatment-for-congenital-heart-defects/feeding-tips-for-your-baby-with-chd

Also Read:

16 Week Old Baby’s Development
Development of 17 Week Baby
Development Milestones of 19 Week Old Baby

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