May 11, 2011

Back to Birth Weight

I just received a comment on a blog post.  The post was called, “Newborn Won’t Gain Weight.”  The comment from Joey, 5/17/2011, said, "What if the child is now 1 month old and still 5oz shy from birth weight? My niece is in the hospital right now. Her parents aren't the brightest and I'm worried. Thanks for writing about this by the way! " 

I'm so grateful that you have found this blog interesting. It isn't meant to give medical advice of any kind, ever.

In this true story, I was seeing the baby every few days at first, but as the inadequate weight gain continued, I was seeing the baby every single day. I was worried about the baby! It's normal for babies to lose weight for the first few days. But they should start gaining weight within about a week or so. Babies who are born bigger tend to lose more weight at first, so it might take them a little longer to regain their birth weight.

Pediatricians often use, as a rule of thumb for this initial weight loss, about 10% as a guide. If a term baby of average weight, say 7 1/2 pounds (about 3400g), loses anything less than 10%, we usually don't worry too much about it. For this average baby, that would be about 12 ounces (about 340g).

We also have a rough guide for weight gain. On average, once newborns start gaining weight, we expect them to gain about 1 ounce a day (~30g). This slows down, of course, as the months go by.

Let's do the math. If our 7 1/2 pound baby lost 10% of her weight by the time she was 5 days old, she would weigh 6 pounds, 12 ounces. She lost 12 ounces. It would be reasonable to guess that it might take 12 days (at a rate of weight-gain of 1 ounce a day) for her to regain that weight. But she only started gaining weight on her 6th day, so she'd be back to her birth weight around day 18. That's about 2 1/2 weeks old. I'm usually pretty satisfied with anything in the 2-3 week range.

Let's do it again for a bigger baby, say 9 pounds (~4100g). Weight loss of 10% would bring the baby down to about 8 pounds 1.5 ounces. If this baby gained an ounce a day, the baby wouldn't be back to its birth weight until closer to 3 weeks of age.

Babies who are born smaller, lighter, or prematurely don't have so much extra, and the 10% rule-of-thumb really doesn't apply. Remember that the baby is not just getting food but also fluid in each feeding. If there's a delay getting breast milk or formula, that's always going to be concerning.

The blog post you commented on was an example of how I manage this as a physician, in the unusual practice I have created. If a baby who wasn't gaining weight was brought to urgent care or to a doctor for the first time, it would be understandable if that doctor, alarmed by the poor weight gain, felt compelled to get some tests to make sure the baby wasn't sick in some way. It would also be reasonable to discourage breastfeeding, at least for the moment, and encourage formula use. Maybe the baby would be admitted to the hospital for intravenous fluids. None of these interventions would be wrong or bad care.

I wanted, as much as possible, to avoid these. I wanted to support and facilitate successful breastfeeding as much as possible. But the baby's health and safety are always, in every case, the most important things I care about. I have one thing that the urgent care or emergency room physician does not have: continuity. I have the power to ask the parent to bring the baby back the next day, and the day after that. I will see the baby on Saturday and Sunday and July 4th, and so on. I can give parents instructions about what to look for, and if they observe these symptoms or have new concerns, they should call me right away. When they do call, I answer the phone and I know the story, I know them, I know their baby. This concept of continuity of care is extremely valuable because I'm less likely to miss a condition that evolves over time. It saves a lot of money, because I'm not sending every child who's sick in the evening to the ER. And I'm not treating every patient for the first time. I can and do order tests and x-rays, when they're needed. I send kids to the ER sometimes.

But I can see this mother every single day, weigh the baby, try first one idea and if that doesn't work, try another. I can find out how the mother is doing emotionally and physically, how much pain she's in and how tired she is. I can find a way to get that baby on the right track.

There's a nice epilog to the story. We did feed the baby formula, but only for a few days. As the baby put on a little weight from the formula, he got a little stronger with his nursing on the breast, and was less famished when he nursed. Mom's body responded well, and they soon didn't need the formula at all. They successfully nursed for more than a year.

As I pointed out in the original post, formula isn't poison. It's an important tool we have available if we need it.

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Please let me know what you think. Do you know a child or situation like this?