Weight Gain in a Breastfed Baby

Breastfeeding is best for your baby for a number of reasons 3. For one, you're never tempted to try and force the "last bit" of milk in the container into your baby, giving him more calories than he needs. Your breast-fed baby might weigh less than a formula-fed baby, but this is normal. Breast-fed babies have a lower rate of overweight and obesity later in life than bottle-fed infants plus a lower risk of developing type 2 diabetes, an article in the fall 2009 issue of "Review of Obstetrics and Gynecology" reports.

Newborn Weight Gain

Breast-fed newborns often lose more weight in the first week after birth and gain it back more slowly than bottle-fed babies. This occurs because it takes a few days for your milk supply to become established, while formula flows out of the bottle from the first time you feed a baby. In a British study published in the April 2008 issue of "Acta Pediatrica," breast-fed babies lost an average of 6.4 percent of body weight before starting to regain weight; 54 percent took longer than eight days to regain their birth weight. Formula-fed babies lost 3.7 percent of body weight and 39 percent hadn't regained birth weight by day eight of life.

Normal Weight Gain

During the first month of life, a breast-fed baby should gain between 4 and 7 ounces per week, once he regains his birth weight, pediatrician and author Dr. William Sears explains 3. From age 1 month to 6 months, he should gain between 1 and 2 pounds per month. Weight gain should slow to 1 pound per months between 6 and 12 months of age, according to the Ask Dr. Sears website 3.

Problems With Weight Gain

Some babies gain faster than others, just like some adults weigh more than others. Look at your baby, not the scale, pediatrician Dr. Jay Gordon recommends 2. If he's nursing eagerly, urinating clear, not dark urine and producing two to three normal stools at age 6 weeks, he's most likely just growing on his own timetable. But when your breast-fed baby doesn't gain as he should and your pediatrician has concerns, it's prudent to try and increase your breast milk supply. If your baby is less than 6 weeks old, nurse eight to 12 times per day, lactation consultant Nancy Mohrbacher recommends, and keep the baby on one breast for 20 to 30 minutes before switching, to ensure that he's getting the fatty, more calorie-dense hindmilk.

Differences Between Breast and Bottle-fed Babies

At age one year, breast-fed babies tend to be leaner, weighing on average 1 pound less than their bottle-fed friends. Formula and breast-fed babies gain similarly in the first four months, but breast-fed babies gain less between ages 4 and 6 months. Breast-fed babies take in fewer calories than bottle-fed babies, not because breast milk is lacking, but because they have greater ability to self-regulate their intake, according to the Ask Dr. Sears website. Breast-fed babies may retain less fluid and also have a different body fat composition than bottle-fed babies, according to Ask Dr. Sears.