The Ultimate Parents Guide To Newborn Weight Loss And Gain

The Ultimate Parents Guide To Newborn Weight Loss And Gain

What's normal when it comes to a newborn's weight, and what are some of the reasons for a baby's weight gain to drop or stop? Read this article to find out...

When your baby is still in your womb, you wait for your ultrasound scan days so you can find out just how well your baby is doing.

But after you give birth, your full attention is now on his weight and which percentile he is in, as markers of his good health and wellbeing.

It’s all too easy to fret about your baby’s weight — including loss of it and not gaining enough (in your eyes).

However, by familiarising yourself with the information presented in this article* about newborn baby weight gain and loss, you can spare yourself of this worry — and also know when worry is warranted.

newborn weight loss

It’s normal for newborn babies to lose some weight initially

Baby weight: loss and gain

Your baby’s weight at birth

Genetics as well as your health and nutrition during pregnancy will determine your baby’s birth weight.

According to the Health Promotion Board of Singapore (HPB), the average Singaporean baby (at 40 weeks) weighs 3.2kg, with most healthy newborns weighing anywhere between 2.5 to 4.5kg.

However, it’s not how much your baby weighs at birth that’s important — it’s the rate of his weight gain and growth pattern over the next few months that is.

The first 14 days

All babies will lose a few ounces from their birth weight within the first few days after birth.

According to the American Academy of Pediatrics, “a 5% weight loss is considered normal for a formula-fed newborn and a 7-10% loss is considered normal for breastfed babies.” This is reiterated by the Australian Breastfeeding Association who say a maximum weight loss of 7-10% is considered normal in breastfed babies.

In fact, according to a study published in Pediatrics, exclusively breastfed newborns (in the study cohort) lost as much 10% or more of their birth weight in the first few days post-birth.

The same study noticed a slight difference in weight loss among vaginally- and C-section-born babies — with 5% of the former losing at least 10% of their birth weight and 10% of the latter losing the same amount of weight.

This immediate weight loss in your newborn is generally no cause for concern, because babies are born with extra weight to sustain them until you get breastfeeding going.

Dr. Jennifer Shu, paediatrician and co-author of Heading Home With Your Newborn, also reassures new mums by pointing out that the colostrum your breasts produce immediately after delivery, has everything your baby needs at this point.

Two to five days after birth, your breastmilk should come in. Following this, you should notice a gradual climb in your baby’s weight — and he should re-gain his birth weight when he’s around 14 days old.

During this time, neonatal experts say you should document a weight gain in your baby of at least half an ounce a day.

newborn weight loss

A baby weight and height chart will help you monitor your baby’s growth.

Making sense of your baby’s growth chart

From the day your baby is born, his weight will be assessed and recorded in a weight-for-age growth chart. The most common chart (and the one that is used in Singapore) is a percentile chart, based on World Health Organisation growth standards.

Importantly, the World Health Organization growth standards are based on healthy, exclusively breastfed babies from six countries across five continents, and can be used whether your baby is breastfed or formula-fed.

They more accurately show how a healthy baby should grow in comparison to older versions based on information gathered from only formula-fed infants.

You can find the World Health Organization child growth standards percentile charts and tables here:

Children will grow along their own ‘curve’, and as long as your baby follows his curve consistently, there is no cause for concern. For example, a baby who is in the 5th percentile and has always been in the 5th percentile is less of a concern than a baby in the 50th percentile who suddenly starts to drop.

“If we see an infant falling significantly on the chart, say from the 60th to the 10th, we’ll have the baby come in for more frequent weight checks and try to feed her more,” says Dr. Shu. “If she’s eating well but still not gaining, we’ll run tests to rule out an underlying cause, like a food allergy.”

Newborn weight: Keep these points in mind

Breastfed babies vs. formula-fed babies

Babies on formula will have much less trouble gaining weight than breastfed babies. In fact, formula-fed babies may even gain too much weight because formula is more concentrated than breastmilk and often, parents want their baby to finish the whole bottle.

Dr Jack Newman, who is an internationally reputed breastfeeding expert and paediatrician, says that too much weight gain is less of a concern for breastfed babies.

This is because breastfeeding babies stop when they’re done (rather than when the bottle is empty) and therefore, are able to self-regulate the amount of milk they drink.

“I wouldn’t worry about rapid growth in a breastfed baby who is content and healthy,” says Dr Newman.

newborn weight loss

How full or dry your infant’s diaper is, is a good indication of if he’s getting enough to eat or not.

Monitor those early diapers

In the first three days post-birth, your little one will pass dark stools, or meconium. By day three or four, his stools should be soft and yellow (if breastfed) or darker and firmer (formula-fed).

If your baby’s stools are not changing in this manner, then experts advise that he may not be getting enough milk.

Another indication that he may not be getting enough milk is if he is not producing enough wet diapers a day. In general, a newborn baby aged two days old will have two to three wet diapers a day. But this should ideally increase to six to eight by the time he is a week old.

If you feel your baby isn’t producing enough wet diapers, or you notice something odd with his stools, please contact your paediatrician without delay.

Average weight gain in the first year

While the general understanding is that a baby should gain, on average, between 140 to 201 grams (five to 7 1/2 ounces) per week, in the first three months, Dr. Newman advises parents not to get too obsessed with monitoring these averages.

Instead, Dr. Newman suggests you should keep in mind that:

“A baby who is following the 95th percentile on the growth chart will be gaining significantly more.

A baby following the third percentile gains significantly less than that. That’s one reason growth curves are a better way to judge how the baby is growing.”

Keep in mind that between three and six months of age, your baby’s average rate of growth will slow down to between 105 and 147 grams per week. And between six and 12 months, it further slows down to 70 to 91 grams per week.

In general, babies will double their birth weight by around five months, and triple it by a year.

newborn weight loss

If your baby is not latching on properly, this could interfere with his weight gain.

When your baby is not gaining enough weight

There may be several reasons for inadequate weight gain** in an infant (or failure to thrive), including the following:

1. Your baby is not latching on properly

It may look simple enough, but helping your baby to latch on properly takes practice for both mummy and baby. If you think your baby is not getting enough breastmilk, Dr Newman says the first step is to improve your little one’s latch.

“It’s important that the mother know when the baby is getting milk rather than just ‘nibbling’ at the breast. When the baby is not drinking much, using compression can help,” he advises.

Breast compression means squeezing your breast while the baby is sucking, but not drinking. It’s like hand-expressing milk into the baby’s mouth.

If you are struggling with getting your baby to latch on, please consult your paediatrician, or a lactation consultant/nurse without delay, as they can guide you with the correct techniques.

newborn weight loss

Tongue tie. Image from LLLI/Pinterest

2. Your baby may have tongue tie

Some babies have tongue tie, meaning the lingual frenulum — the piece of skin that attaches the tongue to the bottom of the mouth — is too thick or too short. This interferes with the movement of the tongue, making it hard for baby to breastfeed.

A clue to watch out for that may indicate he has this condition is if the tip of his tongue curls under when he cries with his mouth open.

If you suspect your baby has tongue-tie, mention this to your paediatrician or lactation consultant, who can check. The remedy for this condition is a quick clipping of the frenulum by a doctor.

Tongue-tie is more of a problem for breastfed babies rather than bottle-fed ones, as the latter use their tongue less to get milk from the bottle.

newborn weight loss

Is your baby too sleepy to nurse?

3. Your baby is not nursing often enough

Newborns should be nursing around every two and a half hours, or, according to La Leche League International (LLLI), about eight to 12 times in 24 hours.

Dr. Shu says that some little ones can tend to be really sleepy, and therefore, forego some feeds. But at this stage, the need to be feeding him at regular interval overtakes your need for a nice, long stretch of sleep — at least until your paediatrician says you can reduce the frequency of feeding.

When your little one doesn’t nurse frequently especially at the initial stages, your body doesn’t get enough stimulation to make more milk, meaning your baby may not be getting enough nourishment. This in turn can make him too tired to nurse.

If you find your baby is drifting off at your breast, do your best to rouse your little sleepy head by rubbing his feet or stroking his cheek. If these methods fail, take him off the breast to wake him up, then re-latch, suggest lactation experts.

newborn weight loss

Prevent supply issues from occurring by making you you get plenty of breastfeeding support at the outset


4. You have supply issues

While it’s difficult to tell if your baby is getting enough breastmilk, as long as he is producing the recommended amount of wet diapers and pooing frequently, you’re doing a great job.

However, to keep up your supply you don’t just need your baby to latch-on frequently — you also need loads of support.

Most often, supply issues develop when new mums don’t have enough support initially, which can have a negative impact on establishing their full supply.

Talk to a lactation consultant, other breastfeeding mothers or a doctor early on, and frequently.

newborn weight loss

Always mix your baby’s formula following instructions precisely.

5. You aren’t mixing formula properly

Dr Shu explains that some parents add extra water to formula to save money or because they think formula is constipating their baby.

Stick to the correct measurements — too much water and not enough nutrients can be fatal to a newborn, if, for whatever reasons, you are giving him formula and not breastmilk***.

Parents, we hope you found this information useful. Remember not to compare your baby and his size or weight to that of other babies.

Each little one is unique and will gain weight at a different rate.

*Please keep in mind that this is a general guide. You should be discussing any matters related to your baby’s health with a medical specialist. 

**Seek medical help without delay if your infant’s weight gain has slowed or stopped. 

***Medical professionals around the world recommend that breastmilk is the best source of nourishment for a newborn baby. They advise at least six months of exclusive breastfeeding. 


American Pregnancy Association

La Leche League International

Australian Breastfeeding Association



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