Milk Production in the Breast

Within the breasts are grapelike clusters called alveoli in which milk is produced under the influence of the hormone prolactin. (See Figure 11.1) The milk travels from these alveoli through lactiferous ducts until it reaches the fifteen to twenty lactiferous sinuses, in which it is stored. These sinuses are located under the areola, the darkened area around the nipple. The raised bumps on the areola that become prominent during pregnancy are called the Montgomery glands. They secrete a fluid that lubricates and prevents bacterial growth on the nipple and areola.

Figure 11.1 Cross section of lactating breast.

Each nipple contains fifteen to twenty tiny openings—one from each sinus—through which the milk flows. Stimulation of the nipple by sucking, or even touching, causes the nipple to become more erect, which makes it easier for the infant to grasp. Sucking or touching also causes oxytocin to be released into the bloodstream. The oxytocin causes the alveoli to contract, which pushes the milk into the ducts and sinuses to make it available for your baby. This process is known as the milk ejection reflex or let-down reflex, and it occurs shortly after your baby begins each nursing. Most women experience a sort of tingling in their breasts during a let-down, along with a surge of milk from each breast, sometimes strong enough to cause a spray to shoot out as far as 12 inches. Occasionally, just hearing your baby cry or even thinking about him can cause a let-down. This let-down reflex can be inhibited by emotional upset, fatigue, or tension. Mothers having difficulty can condition the let-down by developing a nursing routine and using relaxation techniques.

Supply and Demand

Your milk supply is determined by the amount of milk your baby requires. The more he nurses, the more milk you will produce. This is why mothers are able to nurse twins. To establish an adequate supply, you should let the baby nurse whenever he is hungry and avoid the use of pacifiers and supplements (water, formula, or solid food), which would decrease the time the infant nurses at the breast. Encourage your baby to nurse every 2 to 3 hours (eight to twelve times a day). Wait until your baby is skilled at nursing and your milk supply is well established before introducing a pacifier or an occasional supplemental feeding. Otherwise, you might disturb this perfect demand-supply relationship that nature has devised and thus diminish your milk supply.

You will find that allowing your baby to set his own schedule will benefit both of you—the baby will be more content, and you will avoid both breast engorgement and an inadequate milk supply. As your baby grows, his body will require more milk. When he experiences growth spurts, he will want to spend more time at the breast to increase your milk supply. Do not misinterpret these increased feedings as a signal that your milk has “dried up.” The initial fullness that is experienced, as a result of an increase in blood flow and tissue fluid, usually subsides by 6 weeks. If you allow your baby to nurse on demand, after 1 to 2 days of these more frequent feedings, your milk supply will increase and he will return to his normal schedule. The most common times for these growth spurts are between 10 and 14 days, between 4 and 6 weeks, at 3 months, and at around 6 months.

The majority of mothers can develop an adequate milk supply for nursing. Nursing is not possible in cases of complete mastectomy or breast surgery in which the milk ducts were severed. Certain other medical conditions can also affect the mother’s ability to produce sufficient milk. (For a complete discussion of this problem, see “Inadequate Milk Supply”) Women who have had breast augmentation may want to talk to a certified lactation consultant if problems arise. The size of the breasts has no effect on milk production. Size is determined by the amount of fatty tissue. Inability to produce milk is more often the result of cultural conditioning, such as negative myths and discouraging social influences.

Even if you become ill, such as with a cold or flu, you should continue to nurse. Your baby will receive the antibodies that you are producing to fight the illness and will probably not get sick. If he does become ill, he will have a very mild case. If you need to be hospitalized, use an electric pump to maintain your supply or arrange to have the baby brought to you for feedings.

You will feel better if you maintain a nutritious diet while nursing. Although it was previously believed that an extra 500 calories were needed while breastfeeding, recent studies indicate that this estimate is too high. The same principles of good nutrition apply to you as to the rest of the family. You do not need to follow any special or complex diets, although you may be thirstier than before. You should drink sufficient liquids to quench your thirst, but you do not need to drink milk to make milk. If you do not like milk, drink water and fruit juices, and eat foods such as cheese and yogurt to get your calcium. To avoid missing a meal, fix yourself a snack and a drink while your baby is napping. Then, when he wakes up wanting to nurse, grab your snack, and the two of you can relax and enjoy mealtime together. Having one hand free makes it easy!

Be careful to avoid exhaustion, especially during the first few weeks, by getting plenty of rest and relaxation. Do only those household chores that are absolutely essential—fixing simple meals, and doing laundry and light housekeeping. A spotless house is not necessary. Take care only of what bothers you the most, such as the dirty dishes and rumpled beds. Remember that your house will still be standing years from now, whereas your baby will be an infant for only a very short time.

Ideally, during the early weeks, you will have help from your husband, mother, mother-in-law, or a paid employee so that you can devote your time to your new baby. If you do not have help, you will need to use your time wisely. When your baby goes to sleep in the afternoon, you, too, should use that time for napping, rather than running around cleaning house. Your milk supply and your disposition will benefit.