Heather, it can be confusing when you get different opinions from different doctors. Babies are born in different sizes and with different appetites and growth rates, so nobody can tell you exactly how much your baby should eat and how fast he should grow. In general, I believe that you can tell your baby is eating and growing well by observing him, not the scale. Follow your baby’s cues and trust your instincts—feed your baby when he shows you he’s hungry and stop feeding him when he shows you he’s full. If your baby is eating the right amount, he should be satisfied after his feedings, sleep well (waking for one nighttime feeding is normal at this age), and have some alert and active periods. Here are a couple other ways to tell whether your baby is eating the right amount and growing on track:
As a general rule of thumb, bottle-fed babies should drink approximately 2½ oz. of formula per pound of body weight. When your baby weighed 8 pounds 4 ounces, he should have been drinking approximately 21 oz. per day. Now that your baby has grown even more, he should be drinking a little more. If your baby drinks 3½–4 oz. every 3½-4 hours, this falls within the correct range.
In the first six months of life, babies typically grow approximately 6 oz. per week, and double their birth weight by 4-5 months. Your son grew a little more than this in his first two weeks, but not alarmingly so. (Consistently growing 10–12 oz./week would be a little too much—that would mean that at 6 months your baby would weigh 25 pounds, the size of a typical 1-year-old.)
At every medical visit, the doctor should weigh and measure your baby and chart his growth. When I plotted your baby’s weight of 8 lbs. 4 oz. at 2 weeks of age, he was at the 50th percentile (i.e., average size). If your baby is eating the right amount, is healthy, and growing normally, his growth should continue to follow his percentile curve on the chart. (If you want to see for yourself, you can download the growth charts at www.cdc.gov/growthcharts.)
Talk with your doctor again at your next visit. Ask if you can look at your baby’s growth chart together to make sure his growth is on track. Hopefully you can reach an understanding with your doctor about your baby’s nutrition and growth. But if you still feel dissatisfied with your doctor, you can look for another doctor with whom you’ll feel more comfortable. Since you’ll be taking your child to the doctor frequently over many years, it’s important that you find someone who you feel you can trust. (See the article on this web site titled, “Choosing a Doctor for Your Child.”)
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.