How much weight is your baby supposed to gain?

This is one of the most frequent questions I get from new parents. How much weight should the baby lose? How soon should it be back to birth weight? How much is baby supposed to continue gaining?

While this is individual for each human, there are some norms that help us make sure your baby is growing well. The last few weeks of pregnancy your baby gains at least a pound!! So if you have a 37 weeker, instead of a 40 weeker, that makes a big difference. In labor if you have an IV, especially if you have more than one IV bag, it’s common for baby to have extra weight. You can know it’s water weight because instead of peeing once in the first 24 hours your baby might pee 4-5 times! And have a large weight loss in the first 24 hours. In these cases you should work with an IBCLC and consider if using the 24 hour weight is more accurate in your case.

Then babies typically lose 5-10% of their weight, usually between days 1-4, and then will stabilize and start gaining. Most babies are back to birth weight by 10 days old, but all babies should be back to birth weight by 14 days.

When a baby is still below birth weight at 14 days old that requires immediate attention. Best case work with a skilled IBCLC to see how much baby is getting if you are breast/chest/body feeding. Then make a plan to address feeding needs and weight checks.

You might have also heard that babies can gain ½ - 1 oz a day, and that’s enough. Well the bottom line is that’s not enough. Once your baby is back to brith weight the goal is to keep them on the same growth curve. It’s fine to go from 50% to 45% to 52%- small changes aren’t that big of a deal. However there are dark lines on the growth chart and it’s important not to cross them.

I’m adding a photo here of a growth chart. In this case, a baby boy was born at 8 pounds 8 ounces, which was about 75%. Then had weight loss and return to birth weight at 14 days, with a little drop to the 50% line. The next few months are all gaining ½ oz a day, and at 6 months this baby is down to the 2%!!! From birth at 75% to initial drop to 50% then every single weight was a decrease in percentile. This example is to show how it’s not okay for babies to “find their own curve” or only gain ½ an ounce a day.

If you have concerns about your baby’s weight please reach out for support. Infant growth and developement is so important! Let’s work together to optimize it while you can.