Establishing breastfeeding often raises the question of whether to offer one breast or both during a single feeding session. This decision is not based on a set rule, but rather on understanding the milk’s composition and the infant’s feeding behavior. The approach to switching sides directly influences the baby’s nutritional intake, the mother’s comfort, and the long-term regulation of milk production.
The Primary Goal: Achieving Hindmilk Intake
The milk produced during a single feeding session changes composition as the feed progresses, moving from a higher-volume phase to a higher-fat phase. The milk available at the start of a feed, called foremilk, is typically thinner, watery, and rich in lactose and carbohydrates. This lower-fat milk provides hydration and a quick energy boost for the infant.
As the baby continues to nurse and the breast is emptied, the milk gradually becomes thicker and creamier. This later milk is known as hindmilk, and its fat concentration can be two to three times higher than foremilk. The greater caloric density of hindmilk promotes healthy weight gain and provides the satiety that keeps the baby full after a feed.
The central goal of effective nursing is ensuring the infant feeds long enough on the first side to receive the richer hindmilk. If the session is shortened or the baby is switched too quickly, the infant may fill up predominantly on lower-fat foremilk from both sides. This can lead to a foremilk/hindmilk imbalance, potentially resulting in fussiness, gas, and suboptimal weight gain. Since the change in milk composition is gradual, allowing the baby to empty the first breast is prioritized.
Determining Whether to Switch Sides
There is no fixed requirement to nurse on both sides at every feeding; the decision should be dictated by the infant’s needs and the mother’s milk production. For a newborn, especially one who is still regaining birth weight or tends to be sleepy, offering both sides is often recommended. This maximizes overall volume and calorie intake, helping to establish consistent weight gain in the early weeks.
As the infant grows, establishes efficient feeding patterns, and gains weight well, it is common to transition to a one-sided feeding approach. This involves alternating the side offered at each feed, ensuring the baby fully empties one breast before the next session. Many mothers with an established supply find this method sufficient, as the baby receives the necessary volume and fat content from a single, complete feed.
The decision also depends on the mother’s milk storage capacity, which varies significantly between individuals. A mother with a smaller capacity may find her baby consistently needs both sides to feel satisfied, while a mother with a larger capacity may only need to offer one. Regardless of the number of sides, the guideline is to allow the baby to finish the first breast completely before offering the second. Also, begin the next feeding session on the breast that was offered last or feels fuller.
How Nursing Technique Impacts Milk Supply
The regulation of breast milk production operates on a principle of supply and demand; the amount of milk removed signals the body to produce more. Frequent and effective emptying of the breast is the primary mechanism that drives and maintains a robust milk supply. If milk is consistently left in the breast, the body signals production to down-regulate, which can be a necessary adjustment for managing an oversupply.
A technique known as “switch nursing,” where the baby is alternated between breasts multiple times during a single feed, can be used to intentionally boost milk supply. This strategy capitalizes on the repeated stimulation of the let-down reflex on both sides, signaling a higher demand. Conversely, consistently offering only one breast per feed, called “block feeding,” is sometimes used to decrease an excessive milk supply, as the unused breast is not fully emptied.
If a mother has concerns about low supply, offering both breasts at each feeding session is a simple way to increase the frequency of breast emptying and stimulation. For optimal long-term regulation, the goal is to find a balance where the baby is satisfied and the breasts are sufficiently drained. The supply must meet the infant’s growing needs without causing painful engorgement, and production will regulate based on the frequency of milk removal over time.
Signs the Infant is Done with the First Breast
The most reliable way to know when to offer the second breast is by observing the infant’s behavior and the physical change in the first breast. An actively feeding baby starts with rapid, shallow sucks that transition into slower, deeper sucks with audible swallowing. This swallowing indicates the baby is receiving a significant amount of milk, including the higher-fat hindmilk.
The first breast is considered sufficiently drained when the baby’s suck-swallow pattern slows significantly or ceases, becoming more of a light flutter. The infant may unlatch on their own, or their body language will change, such as their hands relaxing from a clenched position. A satisfied baby often appears drowsy or falls asleep, and the mother’s breast will feel noticeably softer than it did at the start of the feed.
If the baby unlatches and shows signs of being content, such as a relaxed body and closed eyes, they may not need the second side. However, if they unlatch but remain alert, begin rooting, or show signs of fussiness, they are ready to be offered the second breast. It is helpful to burp the baby or change their diaper before offering the second side, as this can briefly wake them and encourage continued feeding.