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The Truth About Birthweight

Updated: Jun 2

For most moms, the days following giving birth are anything but stress-free when you factor in all the “must-dos” like navigating breastfeeding, adjusting to life with no sleep, keeping a watch for postpartum complications and red flags in your newborn’s health, not to mention tracking diapers, keeping tabs on the frequency of feeds, and the constant wonder about if the baby is actually gaining weight. For breastfeeding moms, there’s also the wonder about if the baby is getting enough milk and if she will make a full supply.

Looking at weight loss and gain in the newborn is tricky. If a mom has any IV fluids during labor and delivery, the baby’s birth weight can be elevated, which then makes a more drastic loss of weight in the first few days seem more concerning. All newborns lose weight after birth, and up to a 7-10% loss is considered normal. If a baby loses 10% or more of their baseline weight and is not meeting the minimum number of wet and soiled diapers, that is a true concern. Here’s where it gets tricky… the percentage of weight loss is determined by the baby’s weight at the time of birth, whether or not the mother was given fluids during labor and delivery, making some babies' weight loss look worse than it actually is. A more accurate picture of weight loss would be to use the baby’s weight at 24 hours old as the baseline. This gives time for the baby to shed the extra weight from labor medications.

Why is this important to understand? Because lots of moms have labor medications that inflate the baby’s birth weight, and lots of babies appear to lose too much weight in the days following birth and are then potentially unnecessarily supplemented with formula. If the mother isn’t pumping in accordance with the formula supplements, her milk supply could suffer greatly. Too often breastfeeding is sabotaged right off the bat with a misinterpretation of the baby’s weight loss/gain.

Does it make a difference for every baby in every situation? No. But for some, it can make a huge difference. All newborns lose weight after birth and are expected to be back to birth weight by 10-14 days postnatal.

In your birth plan, request for your baby’s weight to be checked at 24 hours old and remember that number. If concerns arise about your baby’s weight loss, you will have it to refer to and can use it as a discussion point with your doctor or midwife before making a plan to automatically supplement.

To calculate the percentage of weight your baby has lost, use the following formula:

  1. Convert the baseline weight into ounces. You can do this by multiplying the lbs by 16 and adding the ounces. Ex: baseline weight: 7 lbs 13 oz [7x16=113 + 13 = 125 oz]

  2. Convert the new weight into ounces as well. Ex: new weight: 7 lbs 6.5 oz [7x16= 113 + 6.5= 119.5 oz]

  3. Then take the baseline weight in ounces and subtract the new weight in ounces. Ex: baseline weight in ounces: 125. New weight in ounces: 119.5. [125-119.5= 5.5 oz]

  4. Then divide that number by the baseline weight in ounces to get the percentage of weight loss. Ex: Ounces lost: 5.5. Baseline weight: 125. [5.5/125=.044]

  5. Move the decimal point two spaces to see the percentage of weight loss: .044 is 4.4%

Nurse your baby on demand, 24 hours a day, waking your newborn to nurse every 2-3 hours during the day or 3 hours at night if they are not waking on their own, until they are back to birth weight, then just nurse on demand and keep tabs on diaper output.

What is “good” diaper output for a newborn?

Day One: 1 pee and 1 poop (0 to 24 hours of life)

Day Two: 2 pees and 2 poops (25 to 48 hours of life)

Day Three: 3 pees and 3 poops (49 to 72 hours of life)

Day 4 and beyond: 4 - 6 wet diapers and 4 - 6 yellowish, seedy, poopy diapers every 24 hours

The first two weeks are very important for setting breastfeeding up for success for the long haul. If you are struggling, concerned, or just need some encouragement and support, reach out to Beholding Baby!

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