Anatomy and PhysiologyAn understanding of how the breast works is essential when working out problems that may arise during breastfeeding.
The breast is composed of alveolar glands which have milk secretory units surrounded by muscle tissue. The muscles help eject milk into ductules. The ductules widen in response to the milk ejection reflex during feeding. Milk ducts lead to the opening in the nipple. During pregnancy, the hormones stimulate growth of the secretory units which results in the breast changes and growth experienced by women.
During each menstrual cycle, the female sex hormones, estrogen and progesterone, stimulate growth of glandular tissue. This development is continued during pregnancy, along with other hormones. When the baby is born, there is a relative drop in the estrogen and progesterone levels and a rise in prolactin levels allowing for dramatic rise in milk production seen in the first few days of life. Suckling stimulates secretion of prolactin as well as oxytocin, the hormone responsible for the ejection or letdown of milk. You need these two hormones for effective breastfeeding. Oxytocin (also known as pitocin) is also responsible for uterine contractions; thus, effective suckling by the infant often causes abdominal discomfort related to uterine contractions.
After your milk comes in around day 3 to 5, your milk production is under autocrine regulation. This means that continued production is dependent on breast stimulation and milk removal. Every time you breastfeed there is a relative increase in prolactin. Prolactin needs to bind to the lactocytes (milk making cells) to signal your breasts to make more milk. If the breasts are full of milk the receptors are distorted and prolactin cannot send the signal. So, more frequent breast emptying sends signals for your body to make more milk.
Breast MilkThere are three types of breast milk. Colostrum, transitional milk and mature milk. Colostrum has a lower energy content but higher salt, protein, vitamin and mineral content than mature milk. Its purpose is to facilitate the transfer of protective antibodies, to assist in the passage of newborn stool or meconium and to aid in the establishment of the appropriate digestive flora- good bacteria- in the gut. Transitional milk will follow and typically your breasts are making mature milk by about day 5. Mature milk is composed primarily of water. The sugar is lactose or milk sugar, the protein is the most easily digested combination of casein and whey and the fat is a combination of polyunsaturated and saturated fats. In addition to nutrients, breast milk has antibodies, enzymes, proteins and immune cells that provide infection protection and help protect and teach your infants developing immune system. All the vitamins and minerals needed for your baby are found in your breast milk. However, if a mother is Vitamin D deficient her breast milk levels of Vitamin D will be low. Given a significant number of mothers have low Vitamin D levels, the American Academy of Pediatrics recommends breastfeeding infants be supplemented with 400 IU of Vitamin D per day.
Establishing Your Milk SupplyWhen your baby is first born they need very little volume of milk. In fact the size of a newborn infant’s stomach is 7 ml or about 1/4 of an ounce (30ml = 1 ounce). This increases over the next several days just as your milk supply does. By day 3 their stomach capacity is about 1 ounce. Your baby may feed more frequently in the hospital but for shorter periods of times. This matches the amount of colostrum available to the size of your newborn’s stomach. Furthermore the frequent short feeds helps put in an order for your milk production.
Timing is also very important. Often the initial breastfeeding takes place shortly after birth. An infant placed on the mother’s abdomen after the cord is clamped, will often inch up the abdomen in search of the breast. If the baby does not feed initially stimulating production by hand expression of colostrum is helpful.
The First WeekKeep your baby close to you. Babies feed frequently early on. This is nature’s way of bringing in your milk. The first days after your child’s birth are when you are putting in orders for your milk supply. Milk is stimulated by emptying of the breasts and frequency. As your milk comes in babies will continue to feed frequently as they are regaining their birth weight. Frequent feedings, also help engorgement resolve more quickly. As your milk is established and your baby is gaining well, they will naturally start to space out the frequency of their feedings.
A baby who is getting enough will have stools change from black and tarry to green and then yellow. Expect several stools a day. Initially your baby will have one wet diaper for the number of days old they are. But after your milk comes in (which usually occurs on day 3 to 5) they will have 6 or more wet diapers per day. A visit in this first week helps if guidance is needed through the process of establishing your milk supply, for troubleshooting any problems, and making sure your baby is getting enough.
Week TwoMost babies have regained their birth weight by 2 weeks. As your baby regains their birth weight they will naturally start to space out their feeds and may fall into the commonly quoted every 2 to 3 hour pattern. Commonly they are feeding 8 to 12 times per day. Their feeds start to get more efficient. Some babies will cluster feed, meaning they feed very frequently for several hours and then take a longer time between feeds. They will continue to have frequent wets and stools. Continue to breastfeed when your baby wants to and if they have been gaining well trust them to space out their feeding frequency to match their needs.
After the First MonthBreastfeeding continues to get more efficient. Typically babies are starting to take less time to feed then they did as a newborn. Some babies will have fewer stools, dropping down to one per day or even one per week. As long as they are gaining well that is fine. Some babies may have fussy times. A common fussy time is in the evening. They may want to feed more frequently and this is okay. If your baby is fussy all the time and not consolable, please schedule a visit for consultation. As your baby starts to sleep longer at night they may be interested in feeding more frequently, or cluster feeding, at times during the day.
The Important Things to Remember
- Look for active sucking and swallowing
- Your baby should be content and relaxed after a feeding
- Good stool production
- Good urine output
- And as always, call if you have any questions or concerns