First, consider why you feel the need to increase your milk supply. Lots of moms think they have a low milk supply, when their milk supply is just fine. If you are exclusively breastfeeding and baby’s weight gain is on target, there is absolutely nothing wrong with your milk supply. This holds true even if baby is fussy, suddenly gets hungry often, will take a bottle immediately after breastfeeding, or if your breasts are soft, and even if you aren’t able to pump any milk. If baby is gaining weight, you DO have enough milk. To maintain a healthy milk supply, most moms don’t need to do anything (besides feed baby when he or she is hungry).
If you do have a low milk supply, you'll need to figure out why. Work with an internationally certified lactation consultant (IBCLC) to help get to the root of your particular supply issue. If your supply is dropping, it may mean that baby isn't effectively removing the milk from your breasts. You may need to help baby achieve a deeper latch, or you may need to wake baby to nurse more frequently. It is very important not to supplement as you try to build your milk supply (unless there is a clear medical reason, like if a newborn has dropped 10 percent of his or her birth weight). Supplemental bottles signal your body to make less milk. Also, using artificial nipples (aka bottles or pacifiers) can lower your milk supply since baby can learn improper sucking techniques. Pacifiers can also lower supply by taking away baby's cues to feed.
Once you have identified the problem and know how to solve it (or if you are trying to boost your supply for another reason, like to increase your pumping output at work or to feed an adopted baby), there are three main ways to increase your milk supply:
Frequent breastfeeding is the number one way to establish and/or grow your supply of breast milk. As a general rule, the more baby nurses, the more milk your body will produce. Nursing baby every two hours (or less) for a couple of days can be very effective in giving your supply a boost. Frequent nursing is especially important in the first days and weeks of breastfeeding as you work to establish a healthy supply of breast milk.
If frequent nursing isn't boosting your supply enough, consider emptying your breasts with a high-quality double-electric pump. Breastfeeding is a supply-and-demand affair: Your body makes milk according to the amount removed from your breasts. Try pumping between feedings or pumping one breast while baby nurses on the other. Continue to pump for five or so minutes after the milk stops coming. The added stimulation will signal your body to produce more milk.
Galactagogues are substances that increase milk supply. Fenugreek, blessed thistle, and alfalfa are herbal galactagogues sometimes used to increase supply, and sometimes prescription medicines are used, like Metoclopramide (Reglan), Domperidone (Motilium), and sulpiride (Eglonyl, Dolmatil, Sulpitil, Sulparex, Equemote). The drug Domperidone isn't widely available in the United States, but it is approved by the American Academy of Pediatrics for use in breastfeeding mothers. (The primary use of the drug is to treat nausea and vomiting caused by other drugs; a boost in milk production is a side effect.) You may be able to order Domperidone online from Canada or other countries. Talk to a doctor and/or board certified lactation consultant (IBCLC) before using any galactagogue.
Rest and stress reduction may make it easier for you to make milk too. And avoid pacifiers and bottles, and give baby only breast milk. (If you have been supplementing with formula, gradually give less and less. This should help baby suckle on your breasts more, leading to increased milk supply.)