by Nancy Mohrbacher, IBCLC

If a breastfeeding baby is not gaining weight normally–either not gaining enough or gaining what seems to be too much–it is natural for a mother to worry. Karen’s baby boy was born full-term and healthy. Although he was exclusively breastfeeding, he was not gaining as much weight as he should. At his one-month checkup, he weighed only two ounces more than his birth weight. Both Karen and her doctor were concerned. Lana’s baby, on the other hand, who was also exclusively breastfeeding, had gained four pounds by his one-month checkup, and she was worried that he was gaining too much.

WHAT’S NORMAL?

Most newborns lose weight during their first three to four days after birth. Because babies in utero float in amniotic fluid, they are born with extra fluid in their tissues, which they need to shed. During these first days after birth, a weight loss of up to 10% is considered normal. For a baby born at 7 lbs. 8 oz., a 10% weight loss would be 12 oz., bringing his weight down to 6 lbs, 12 oz. Weight gain should always be calculated from this lowest point, rather than from birth weight.

During these first three or four days, the exclusively breastfeeding baby receives colostrum from his mother’s breast. This special first milk, usually yellow or gold in color, is small in quantity (teaspoons, not ounces) and has high concentrations of nutrients and immunities. Colostrum is produced in small amounts at first to slowly ease a baby into feeding by mouth. Because baby is shedding extra fluids, he has no need for more milk during this time. Before the mother’s milk increases on day three or four, a breastfeeding baby usually wets only one or two diapers per day and passes meconium, the first dark and tarry stool.

When the mother’s milk production increases, she begins to produce a combination of colostrum and mature milk called “transitional milk.” By ten days to two weeks after birth, her milk gradually changes to the watery-looking, bluish mature milk. If breastfeeding is going well, about three to four days after birth the number of wet diapers and bowel movements begins to increase as the mother’s milk increases. Bowel movements change from black to green to yellow-green to yellow in color and become loose and unformed (the consistency of split pea soup).

At the same time, baby begins gaining weight. Normal weight gain for the first three to four months is four to eight ounces a week, or between one and two pounds a month. From four to six months, this rate of gain normally slows to three to five ounces per week and by six to twelve months to one-and-a-half to three ounces per week.

Between weight checks, a mother can be sure that her baby is getting enough milk by keeping track of the number of feedings (ideally at least eight to twelve) and the number of bowel movements every 24 hours. The number of bowel movements is more significant than the number of wet diapers, which may be hard to gauge when super-absorbent disposable diapers are used. Because fat sticks to a mother’s milk ducts, the first milk a baby receives as he nurses (known as the “foremilk”) is watery and thin. As the baby continues to nurse effectively, fat is squeezed into the milk, causing the fat content of the milk to increase as the volume decreases. The fatty milk baby receives near the end of the nursing (known as the “hindmilk”) creates stools and puts on weight, so if a baby has at least two to three good-sized stools per day, this is a fairly reliable indicator of good milk intake. Because a baby receives the watery foremilk first, a mother can be sure that if her baby has enough stools that that he has also received the fluids he needs.

If a baby younger than six weeks has fewer than two to three good-sized stools per day, this is a red flag to check his weight. If his weight gain is good, then all is well. Although it is unusual, this can be normal for some young babies. Fewer bowel movements per day with good weight gain is more common among babies older than six weeks.

SLOW WEIGHT GAIN

When Karen found out that her baby was gaining slowly, she felt worried, guilty, and inadequate, but her doctor assured her that her baby looked fine and that weight gain can almost always be improved without compromising breastfeeding. He began by carefully calculating the baby’s progress. Although the baby was only two ounces over birth weight at one month, they looked back at his records to see what he had weighed at three to four days of age. At three days the baby had lost eight ounces, so by calculating weight gain from that lowest point, they discovered that Karen’s baby had actually gained ten ounces during that first month, or slightly less than four ounces a week.

In other areas her baby was progressing well. He had grown normally in length and head circumference, his skin tone was soft and moist, he had good muscle tone, he was alert, and he was developing normally in every other way. This encouraged Karen and the doctor. Because the baby was growing and developing well, the doctor suggested that Karen work to increase her milk supply rather than supplement with formula.

Then the doctor asked Karen about her baby’s breastfeeding and sleeping patterns. Karen told him that her baby had been sleeping about eight hours a night since birth. During the day he nursed about every three hours, which meant he had been nursing about six times a day. Also, when she nursed him, Karen routinely switched the baby from the first breast to the second after about ten minutes.

Karen’s doctor, whose large practice of nursing mothers had taught him about good breastfeeding management, knew that breastfeeding babies usually need to nurse at least eight to twelve times a day in order to gain well. So he advised Karen to start waking her baby at night to nurse, allowing him to sleep for one long four-to-five hour stretch, and then waking and stimulating him so that he was alert enough to nurse well every two to three hours after that and for the rest of the day. This meant Karen put her baby to bed at ten o’clock as usual, but woke him to nurse at 2:30 am and 5:30 am, as well as nursing him more often during the day, bringing the total number of daily nursings up to ten to increase her milk supply. Because milk is produced on a supply-and-demand basis, if a baby is nursing actively and effectively, the more often a mother breastfeeds, the more milk she will make.

The doctor also suggested that Karen allow her baby to finish the first breast and come off on his own, rather than switching him to the second breast after ten minutes. Finishing the first breast first gives the baby more calories at each feeding by insuring that he gets more of the fatty hindmilk. If a baby is switched from the first breast too soon, he may fill up on the watery foremilk at both breasts but not receive enough calories from the fatty hindmilk to put on weight.

Not surprisingly, Karen reported that her baby had been having fewer than two to three bowel movements a day. However, after Karen began following her doctor’s recommendations, almost immediately her baby began to have more wet diapers and stools. At his weight check the next week, the doctor confirmed that the baby was gaining weight more quickly and that his weight gain was now in the normal range.

As Karen found, the most common cause of slow weight gain in the breastfeeding baby is not nursing often enough or long enough. But occasionally, there may be other reasons. A baby who is not sucking effectively will not get as much milk for his efforts and will not stimulate his mother’s milk supply, resulting in a slow weight gain. Illness in the baby may affect suck or weight gain. Babies with a cleft lip and/or palate, Down Syndrome, or neurological problems may gain weight slowly no matter how they are fed. Some illnesses in the mother, particularly if they are untreated, such as underactive thyroid, diabetes, and anemia, can affect a mother’s ability to make milk. Pregnancy also decreases a mother’s milk supply, and use of combined oral contraceptives and certain other medications have been found to decrease milk supply in some women. A retained placenta and some types of breast surgery or injury may also affect a mother’s milk production. A mother in any of these unusual situations needs to seek help from a breastfeeding specialist and have her baby under a doctor’s care.

RAPID WEIGHT GAIN

Lana’s baby–who had gained four pounds during his first month–was gaining weight more rapidly than the norm, and this had Lana worried. Was she dooming her baby to a life as an obese child and adult?

Her doctor quickly reassured her that a baby who is receiving only mother’s milk is receiving a food that has no “empty calories,” as do highly processed foods. He also emphasized that there is no evidence that a baby who gains weight rapidly on human milk will have weight problems later on. In fact, the fat that is accumulated in the relatively inactive pre-toddler stage is a preparation for the highly active time when the busy toddler may not want to take time to eat. Usually by age two or three the rapid-gainer slims down naturally.

The doctor also explained that there are hazards in trying to limit a baby’s weight gain by putting him on a diet. The young child needs nutrients to produce all types of cells, brain and nerve, as well as fat cells. As with an adult, the nutritional needs of a baby vary from individual to individual. Reassured, Lana went home and continued to breastfeed her baby on cue, confident in his ability to regulate his own feedings according to his needs.