After birth, the newborn undergoes a multitude of changes to adapt to extrauterine life. Among them, weight loss . All newborns lose weight after birth and regain it progressively as the days go by. But this weight loss is often a matter of concern for parents and health workers. How much weight is it normal for them to lose? When will they get it back? Why is it that some babies lose more than others?
Why do newborns lose weight?
The vast majority of newborns (I would dare say all) lose weight after birth. It is considered something physiological , that is, normal. The reasons are not exactly known but it could be because the fetus inside the uterus has an excess of extracellular fluids and loses part in its transition to extrauterine life.
The expulsion of meconium (that blackish-green material that filled your intestine inside your gut) may also be, in part, responsible.
In addition, weight loss can be a consequence of fat loss , since newborns burn it to use it as an energy source in the first days of life.
How much weight is normal for them to lose and when do they regain it?
Various studies have been carried out analyzing the weights of many newborns throughout the first days of life and all seem to agree that around 6% of birth weight is lost .
This systematic review includes 11 studies that analyze weight loss in the newborn. It concludes that newborns lose on average between 5.7% and 6.6% of their birth weight, that the greatest weight loss is usually around the second or third day of life and that they regain it in the first two weeks of life .
Bertini et al., In 2015, analyzed the weight every 12 hours of 1,760 full-term newborns, by vaginal delivery and without complications. All of them had skin-to-skin contact after delivery and were exclusively breastfeeding. They lost an average of 6% of their birth weight, which is consistent with data from previous studies. They also found that the maximum weight loss occurred between 43 and 72 hours of life (that is, second or third day).
These authors created graphs to track weight loss during the first 72 hours of life.
Which Babies Lose the Most Weight?
Several studies have been carried out and it has been seen that weight loss is greater in newborns by cesarean section than if they have had a vaginal delivery.
Specifically, in a study in 2015 they analyzed the weights of more than 160.00 term newborns and it was observed that 5% of those born vaginally and 10% of those born by cesarean section had excessive weight loss at 48h , and that this percentage rose to 25% in the case of cesarean section at 72h of life.
Greater weight loss has also been documented in breastfed newborns than those who are bottle fed . This is how Macdonald saw it in 2003 when he studied more than 900 newborns: those who were bottle-fed lost an average of 3.5% of their birth weight while those who were breastfed lost an average of 6.7%. They also found differences in terms of weight recovery; bottle-fed babies regained their birth weight earlier (at 6.5 days of life on average), while those who were breastfed took an average of 8.6 days.
Greater weight losses have also been documented in older mothers and first-born .
When is weight loss considered excessive?
We have seen that newborns usually lose around 6% of their birth weight. However, up to 8-10% may be within normal limits . The IHAN initiative states that if the weight loss is greater than 7% it may mean insufficient milk transfer and the Academy Breastfeeding Medicine recommends in its protocol number 3, that if a baby loses between 8 and 10% of birth weight a comprehensive review of breastfeeding technique is made.
The inability of a mother to produce enough milk, called primary or true hypogalactia, is very rare. However, it is relatively common for mothers to produce little milk due to poor technique (for example, very rigid schedules, poor latching …) or for babies, for certain reasons (for example, a short sublingual frenulum, prematurity … ) have difficulty expressing as much milk as they should.
On the other hand, an excessive loss of weight does not always necessarily indicate a failure of lactation as it could also be due to an excessive supply of intravenous fluids to the mother during childbirth.
Excessive weight loss is associated with complications in the neonate such as jaundice and dehydration and could lead to more serious problems such as kidney failure, thrombosis, even seizures.
How do I know if my baby is eating well?
This is one of the things that most worries parents, especially if their babies are breastfed because they cannot measure how much they are taking. Newborns receive very small amounts of colostrum in the first days of life, but this is enough to meet their needs. The transition to mature milk is progressively being made and the amount they drink also increases.
If during the first month of life you take between 8-12 feedings a day , wet at least 4-5 pee diapers a day and have several bowel movements a day , you are satisfied and calm after taking it, it is likely that you are eating well.
Weight is, in most cases, a good indicator (and objective) that a baby is eating well. During the first 4 weeks of life, the infant should gain around 20g per day . The BFHI initiative recommends using the WHO growth charts to assess weight as well as taking the minimum postpartum weight (and not birth weight) as a reference.
How to avoid excessive weight loss in the newborn?
All newborns are weighed at birth and at discharge (usually between the second and fourth days of life). The pediatrician can then detect if the weight loss is excessive (remember that the greatest weight loss occurs between the second and third day of life). In the event that the weight loss is greater than 7%, the breastfeeding technique (or the amount of bottle) should be evaluated to ensure that the milk supply is sufficient. In some cases it may be necessary for the baby to take supplements for a few days.
It is recommended that all newborns be reassessed 48-72 hours after discharge . If the weight does not increase with the passing of the days (some authors put the cut on the sixth day) or the weight at birth is not recovered at 10-15 days of life, the newborn should also be evaluated as well as the evaluation of the feeding technique.
In the event that the intake is adequate, there is a good breastfeeding technique but low weight gain persists, other medical problems should be ruled out.
If as parents you have the impression that your baby eats little, you see him very sleepy or, on the contrary, irritable; he wets less than 4-5 pee diapers a day and / or you have the impression that he is never satiated, do not hesitate to consult. .
In summary, all newborns lose weight after birth, with this maximum weight loss around the second and third day of life. Breastfed babies, those born by cesarean section, and first-borns lose more weight.
Excessive weight loss (greater than 10% of birth weight) can lead to complications. To avoid this, good control by the pediatrician is essential, ensuring that the breastfeeding technique (in the case of breastfed babies) is correct and knowing the warning signs that indicate that a baby is eating little.
In Babies and more | Does the baby have to be awakened to feed him at night? Newborns may take more than two weeks to regain their birth weight
