Expected weight gain in a breastfed infant - Evidence Based Babie
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Breastfed baby expected weight gain.

Expected weight gain in a breastfed infant

How much weight should a breastfed baby be gaining?

The number 1 question and worry in breastfeeding parents are usually “how do I know if my baby is getting enough milk?”. This question is usually followed by the answer “ensure baby has adequate amounts of wet and dirty diapers and is gaining enough weight.”

But more often than not, care providers may wrongfully inform parents that their baby’s weight gain is either too much or not enough, when in fact, it’s actually the perfect amount of weight gain. Why does this happen you ask? Well, sometimes they may use outdated growth charts that’s based on formula fed babies. Other times, it’s due to having no experience with breastfed babies. It’s important to remember that a lot of healthcare professionals have little to no training in breastfeeding, and they simply don’t know any better and probably don’t mean harm.

Parents may also wonder how much weight gain is considered “enough”.

It’s important to take note that weight gain will greatly vary from 1 child to another and factors such as gestation at birth, birth weight, weight loss at birth and gender all makes a difference in weight gain. But there are averages on what you may expect.

The importance of monitoring a baby’s weight gain

Monitoring a baby’s weight gain is a crucial part of assessing a baby’s overall growth and well-being. Adequate weight gain indicates that a baby is receiving enough breast milk, which is essential for their optimal development and well-being.

It is important to remember that weight gain should be considered along with other growth factors, such as length and head circumference.

Weight Gain in the First Two Weeks

During the first two weeks after birth, most babies will lose some of their birth weight before starting to gain again. This is completely normal. The average weight loss ranges from 5% to 8% of their birth weight. Up to 10% may be normal in some cases, especially if the mother received prolonged IV fluids. This loss is primarily due to fluid loss and is considered a normal physiological process. After the initial weight loss in the first few days, babies should start to gain weight again. It is usually expected that a baby is back to their birth weight by 2 weeks of age.

Weight Gain in the First Four Months

In the first four months of life, breastfed babies typically experience rapid growth. The average weight gain can greatly vary, but a general guideline is an average of 20-40g per day or 140-280 grams per week.

If the weight is less than 140g per week or much more than 280g, it may warrant a consultation with a Board Certified Lactation Consultant (IBCLC) to do an in depth assessment to ensure everything is going well with breastfeeding.

It is important to note that each baby is unique, and there can be variations in weight gain patterns. Some babies may experience growth spurts and have periods of more rapid weight gain, while others may have more gradual growth. It is the overall trend of weight gain and the baby’s individual growth pattern that should be considered, rather than focusing on specific weekly or monthly gains at all times.

Weight Gain from 4 Months to 1 Year

After the initial rapid growth phase in the first 4 moths, the rate of weight gain tends to slow down. From four months to one year of age, breastfed babies typically gain weight at a slower pace compared to what they gained in the first 4 months. On average, babies gain around 110-200 grams per week during this period.

Just like during the first 4 months, if your baby is gaining less or a lot more than the average weight gain per week, it may warrant a consultation with a Board Certified Lactation Consultant (IBCLC) to do an in depth assessment to ensure everything is going well with breastfeeding.

Factors Affecting Weight Gain

While the WHO 2006 growth charts provide valuable reference points, it is essential to consider individual factors that can influence a baby’s weight gain, such as:

Feeding Patterns
If a baby is not fed regularly and on demand, it may cause a falter in their weight gain and overall growth.

Effective Milk Transfer Ensure that your baby is latching and breastfeeding effectively from the start. This may seem obvious, but a proper latch allows for efficient milk transfer.

Diaper Output
Monitoring your baby’s diaper output can provide additional insights into their milk intake. In the first few weeks, expect around six or more wet diapers and at least two to four bowel movements per day. After the first 4-6 weeks, the number of bowel movements might decrease to every few days up to 10 days with no bowel movements, but urine output should always remain the same.

Satisfied Baby
Make sure your baby is content after most feeds. Being put down and crying is usually due to the fourth trimester and not feeding related.

Growth Milestones and Development
In addition to weight gain, length and head circumference should be monitor as well. Your baby should also meet their developmental milestones as expected.

Health and Well-being
Your baby’s overall health and well-being should also be a factor. A healthy and active baby who is content after most feedings, is generally an indication of adequate milk intake.

Monitoring a breastfed baby’s weight gain is an essential aspect of ensuring their nutritional intake and overall well-being. It is important to remember that every baby is unique, and there can be variations in individual growth patterns. Along with weight gain, consider other factors such as feeding patterns, effective milk transfer, diaper output, and your baby’s overall health and development.

If you ever have any concerns about your baby’s weight gain or breastfeeding, it is recommended to seek guidance from a healthcare professional or an International Board Certified Lactation Consultant (IBCLC) who can provide personalized support and assistance.

Additional information and resources:

WHO growth charts

An observational study of associations among maternal fluids during parturition, neonatal output, and breastfed newborn weight loss


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We take every effort to ensure that we stay up to date with the latest research and that we only provide you with the best possible evidence based information available.

Online information will never be a substitute for individual support by a qualified healthcare professional.

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