8-month-old baby health & growth guide

We’ll be the first to say it: Keeping an 8-month-old entertained all day is not for the faint of heart. Your mini wants to get into everything right now, exploring, touching, trying, tasting… which is good for their developing sense of independence, but, um, not so good for your sanity, perhaps. While you can appreciate their newfound enthusiasm, gone are the days where you can set them in a safe spot—and expect them to stay put. But we also know those sweet baby giggles seem to somehow melt all the frustration away. Here’s what else to know about your baby’s health and growth this month.  

Related: 8-month-old baby milestones

8-month-old baby nutrition

Is your hungry bub turning up their nose at certain foods? Stay the course. While babies may start displaying food preferences now, according to the American Academy of Pediatrics, it may take as many as 10 to 15 exposures to a food before babies are really willing to give it a shot. Staying consistent with whole-food offerings like fruit, whole grains, lentils, eggs and veggies from an early age can pay off in spades.

If your babe is teething this month, adding pureed fresh fruit to a mesh teether or strainer can provide soothing (and delicious) relief. 

The AAP and La Leche League (LLL) recommend the following feeding timeline and amounts for 8-month-olds:

• Solids: Offered 2 times per day or at family mealtimes
• Breast milk: Up to 8 ounces every 4 to 5 hours
• Formula: 7 to 8 ounces every 5 to 6 hours

While offering solids, the recommended serving sizes for a 8-month-old are:

• Infant cereal (single grain) mixed with breast milk or formula: 5 to 8 tablespoons (optional)
• Fruits: 2 to 3 tablespoons
• Vegetables: 2 to 3 tablespoons
• Shredded meats, eggs, yogurt and soft-cooked plant-based proteins, such as lentils: 2 to 3 tablespoons
• Starches: ¼ to ½ cup simple carbs, such as pasta, mashed potatoes, bread

Read more: 8-month-old baby feeding schedule & amounts

Does your baby need vitamins? 

Your little one likely got all the nutrients they needed from breast milk or formula for their first 6 months of life (though vitamin D drops may have been warranted). Now that your baby is over 6 months, and even though they’re starting solids, they should still be taking vitamin D, and in some cases, supplementing with iron and omega-3 fatty acids may also be helpful. Here’s what to know. Of course, if you’re considering giving your baby any supplement, always chat with your pediatrician first.

Vitamin D

All formulas are required to include enough vitamin D to meet your baby’s needs. As long as they drink at least 32 ounces of formula daily, you won’t need to supplement. But vitamin D is not efficiently transferred through breast milk, and it’s also not readily available in many foods, so if baby is exclusively breastfed or combo-fed with some breastmilk, they will need additional vitamin D, usually in the form of oil-based drops. 

Iron

Now that solids are becoming a more regular part of your little one’s diet, aim to up their intake of iron-rich beans and legumes, broccoli, leafy greens and beef. AAP recommends oral iron supplements for breastfed babies to decrease the risk of deficiency until you introduce iron-containing solid foods. (Formula-fed babies may not need supplementation as many formulas are fortified with iron—just double-check the label.) If you’re worried your baby isn’t getting enough, check in with your doctor about starting an iron supplement. They should also test your baby’s iron levels at 12 months. 

Omega-3s

It’s not a required supplement like vitamin D, but DHA, a type of omega-3 fatty acid, can be helpful in preventing allergies and eczema and supporting brain development in babies. It’s regularly added to some formulas, and some does pass through breast milk, but your little one may not get a therapeutic amount unless you regularly consume fatty fish. You could consider taking a supplement to increase the amount of DHA in your breastmilk, or use a combination vitamin D and DHA drop to offer your baby.

Related: Does my baby need vitamins?

8-month-old baby weight

For babies up to 2 years of age, the Centers for Disease Control and Prevention (CDC) recommend using the World Health Organization (WHO) weight and length charts. 

The WHO growth charts for babies 0 to 2 years are based on what is standard for a predominantly breastfed infant. According to the organization, the WHO charts reflect growth patterns among children who were predominantly breastfed for at least 4 months and were still breastfeeding at 12 months. The American Academy of Pediatrics (AAP) recommends continuing to breastfeed for at least two years, as long as it benefits both mother and baby. 

How much does the average 8-month-old weigh?

Your little should still be gaining some weight each month, though that rate has significantly slowed down as compared to their first 6 months of life. 

According to the WHO:

• An 8-month-old baby boy in the 50th percentile weighs 19 pounds (8.6 kilograms) 
• An 8-month-old baby girl in the 50th percentile weighs 17 pounds, 7 ounces (7.9 kilograms)

What factors contribute to an 8-month-old baby’s weight?

Your baby’s weight may be a factor of how much they’re eating, their assigned sex and their activity levels. 

Assigned sex at birth: Male babies tend to be slightly heavier and gain weight slightly faster than female babies.

Daily milk intake: The amount your baby takes in at each feeding plays a role in their weight. Many babies are still breastfeeding or taking bottles of formula 4 to 6 times per day at 8 months.

Activity levels: Your little one is working on bearing more weight in their legs this month in preparation for walking. Baby’s activity levels may factor into their overall weight, as physical activity helps build strong muscles and bones.

Related: Activities for a 8-month-old: Fostering baby’s development

8-month-old baby length

In month eight, you can expect your baby to grow less rapidly than in previous months, but they’ll still add another ½ inch to ¾ inch (1 to 2 centimeters) in length.

How long is the average 8-month-old?

According to the WHO:

• An 8-month-old baby boy in the 50th percentile is 27 ¾ inches long (70.6 cm)
• An 8-month-old baby girl in the 50th percentile is 27 inches long (68.7 cm)

What factors contribute to an 8-month-old baby’s length?

Length, or height, can be related to several factors, including physical activity, nutrition during pregnancy and after, sleep and overall health. But the primary player is usually genetics: kids tend to resemble their parents in height.  

Related: When will my baby start walking? Experts share there’s a wide range 

Growth charts and percentiles 

At your baby’s next well-check, which will be after they turn 9 months, ask the pediatrician if you can see their growth chart. At each visit, your child’s pediatrician has been carefully plotting their weight, lengths and head circumference on a growth chart, which offers a look at how a baby’s growth may be compared to that of other babies who are the same age and sex. 

Reading a growth chart comes down to two factors: Looking at the percentiles and the overall growth curve. For example, let’s say your baby’s weight is in the 40th percentile. That means that 60% of babies of the same age and sex weigh more, and 40% of babies weigh less. 

But try not to stress about comparing numbers here. Growth percentiles are just one metric used to track your baby’s development—all babies grow at their own pace. And trust that babies can be healthy whether they’re in the 10th percentile or 90th. What’s most important is whether your infant has stayed around the same percentile for a while or if they’ve significantly jumped up or dropped down. Doctors are checking for sustained growth over time, for the most part. 

Growth spurts

Your mini me likely went through several big growth spurts in their first six months of life, but because growth slows down between months 6 and 12, you might not see another significant growth spurt until around 9 months and again around their first birthday. Relish in the fact that you may not need to size up in onesies or diapers for a bit, but here are the signs to look for when it’s time. 

How to tell when it’s time to go up a diaper size

• Your baby’s diaper is leaving red marks where it touches their skin
• The diaper no longer fully covers their bottom
• The diaper is leaking more than usual, or not able to contain the contents
• You can’t comfortably slip two fingers under the diaper waistband

If it’s time to graduate to the next diaper size, you can try to find a home for any unused diapers by offering them to a friend with kids in a similar age, donating them to a diaper bank or seeing if the company you purchased them from will accept returns of unused diapers or unopened boxes. 

When should I worry about my baby’s growth?

At each of your baby’s well-checks, the pediatrician will be checking to make sure your child is exhibiting steady, sustained growth over time. If they’re worried about your baby’s growth curve, they’ll let you know. 

Otherwise, keep focusing on making sure your baby is eating and drinking normally, is having regular wet and dirty diapers on a schedule that feels pretty standard for them, and is meeting or working toward their 8-month developmental milestones. If you have concerns about your baby’s growth, be sure to bring it up with the pediatrician. 

8-month-old baby sleep 

We hate to break it to you, but there’s another sleep progression coming. The 8-month sleep regression/progression is timed with a big developmental leap, and might signify some interrupted sleep for you and your little love. Teething and increased mobility are likely to blame, says notes Rachel Mitchell, a certified sleep consultant and founder of My Sweet Sleeper. But take heart that sleep progressions also mean your little one is on their way to becoming an *even better* sleeper.

The best thing you can do to make it through a sleep progression with your baby is maintain the sleep cues and routines that you have already set up—and avoid making any sudden shifts. “Try to stay as consistent as possible and don’t make any major changes during this time,” Mitchell suggests.

The American Academy of Sleep Medicine notes that at 8 months old, your baby should be getting between 12-16 hours of sleep per 24 hours. 

What baby sleep looks like at 8 months:

• Your baby may be taking 2 naps and 1 late-afternoon shorter nap per day
• Your baby may no longer need to eat at night
• Your baby may be awake for 2 to 2.75 hours at a time

Your little one should still be aiming for 3 naps per day, even if that last nap is much shorter. Mitchell doesn’t recommend dropping the third nap until your baby is between 9 and 10 months old.

Read more: How much sleep does an 8-month-old baby need?

Diapering an 8-month-old

Having now been eating solids for around two months, you’re probably getting a better handle on what’s normal for your baby in the diaper department. Your baby’s poop should be pretty well formed but still have a somewhat paste-like texture. 

If their stool is solid or pellet-like, it could be a sign of constipation. Check in with the pediatrician just to make sure. Also make note of any colors that seem out of the ordinary, like white, black or red. (Brown to yellow to green can still be normal.) Otherwise, you should still expect around 5 to 8 wet diapers per day, and a regular bowel movement schedule of one or more poops per day.

Caring for an 8-month-old

The next well-check with your child’s pediatrician won’t be until 9 months, but if you have any questions, they’re always just a phone call away. In the meantime, here’s what to know about baths and care for your bubbly babe. 

Baths

Once your tot is even more confident in their sitting skills, which might happen this month, they can graduate to taking baths in the full-size tub (rather than their baby bath tub). Start by filling the tub with just an inch or two of water, and then placing baby in the bath feet-first in a safe and secure way, ensuring that they’re able to sit up unassisted. To make the tub surface less slippery, you could place a suction bath mat or even a bath towel at the bottom of the tub before filling it with water. 

Be sure to provide constant supervision while your baby is in the bath, just as you did when they were using a baby tub. If you need to leave the bathroom for any reason, bundle baby up in a towel and take them with you. 

Related: 14 bath safety tips for kids of all ages

Bumps and bruises

Now that your baby is working on crawling and scooting and rolling and sitting (so many new skills!) bumps and bruises are bound to happen as they get bolder in exploring their environment. These small injuries happen no matter how well you babyproofed—they’re nearly impossible to avoid, says AAP. “Just be matter-of-fact about these mishaps. Offer a quick hug or a reassuring word and send her on her way again. She won’t be unduly upset by these falls if you’re not,” the organization writes. 

Keeping a kid-friendly ice pack and some arnica gel on hand can help reduce the pain and bruising level, however. If you’re worried about a possible head injury, reach out to your child’s pediatrician to run through the symptoms you might be seeing. 

Is my baby too sick for daycare?

Most children get anywhere from eight to 10 colds by the time they turn 2—and if your little one has started daycare, it may seem like you’re seeing a new illness come home every other week. But how can you tell if your little one is OK to attend, or if you should keep them home with you or another caregiver? Some daycare and childcare providers may have a flow chart or other set of guidelines that they request parents follow, but if not, here’s how to tell.

When to keep your baby home from daycare

AAP recommends keeping your child home if they are experiencing the following:

• Fever above 101ºF
• Vomiting two or more times in the past 24 hours
• Diarrhea in the past 24 hours that’s not caused by a change in diet
• Abdominal pain for more than 2 hours
• Mouth sores with drooling
• Skin sores that are weeping that cannot be covered with a waterproof bandage
• Rash with fever

As always, reach out to your child’s pediatrician for guidance if your baby is experiencing any of the above symptoms. 

Related: Febrile seizures can be scary—but usually aren’t cause for alarm, experts say

A note from Motherly on self-care while caring for an 8-month-old

Remember, motherhood can fill your cup completely—and drain it at the same time. It’s that constant push-pull of bliss and sheer exhaustion that can be hard to reckon with on a daily basis. If you’re barely making it through til bedtime, ask for more help—there are people in your life who want to help you. And if the things you used to love are no longer giving you joy or you’re feeling so unrecognizable from your former self that you’re worried, consider seeking mental health support. Postpartum depression can set in anytime in the first year after birth—and resources are out there.