Two to four days after birth, mothers may awaken to find their breasts have grown two cup sizes overnight. It's those milk-making hormones at work! "Has your milk come in yet?" asks the nurse. Mom can answer with a definite "yes!"

This dramatic increase in breast size and fullness is called physiologic engorgement. It is caused by postpartum changes in hormone levels, which kick off the milk production process and also increase blood circulation to the breasts.

It's not that you didn't have milk before. Your body began producing colostrum, the first milk, late in pregnancy and made more immediately after birth as your newborn feeds at your breast. It's more accurate to say that the milk supply suddenly increases rather than to say it "comes in." Physiologic engorgement is usually more dramatic and uncomfortable in first-time mothers and lessens in intensity with subsequent pregnancies.

The sudden fullness and tightness may be a bit uncomfortable during those early days when your breasts seem to fill up faster than your baby can empty them. Some mothers even run a slight fever when their breasts are engorged.

Frequent breastfeeding is the best way to prevent and treat engorgement. Relief comes when baby gets the milk flowing and empties the breast. Once you and your baby settle into a comfortable balance of milk production where the supply equals the demand, the discomfort will pass. The swelling will subside and your breasts won't be so enormous, but they will continue to make milk steadily and efficiently.

Engorgement can lead to other problems, so it's important to treat it promptly. When the breasts swell with fluid and milk, the nipple may flatten out, making it more difficult for baby to latch on correctly. Baby can suck on only the end of the nipple and can't get enough of the areolar tissue into her mouth to compress the milk sinuses and empty the breast. Engorgement gets worse, while baby remains hungry. As the hungry baby sucks harder but incorrectly, the nipple gets traumatized and painfully sore. Eventually, the body decides not to make so much milk, which ends the engorgement, but may lead to problems with milk supply if baby is still not latching on and sucking well. Fortunately, you can keep normal physiologic engorgement from becoming a problem. Here are some suggestions for coping with breast fullness:

• Teach baby efficient latch-on in the first days after birth. It's easier for a baby to learn to latch on correctly on the first and second day when your breasts are softer, before your milk comes in. Baby should grasp the breast with a wide-open mouth.

• Room-in with your baby immediately after birth and breastfeed frequently. This will minimize problems with engorgement and get your milk supply attuned to baby's needs more quickly.

• Nurse often during the night as well as during the day. In the first month or two, a baby who sleeps for four or five hours at a time is a mixed blessing. Mother gets a chance to rest, but her breasts become engorged. Wake baby every two hours during the day and don't let him sleep more than four-hours straight at night.

• Do not limit the length of feedings to five or ten minutes to protect your nipples. Protect your nipples by being sure that baby latches on correctly. Limiting the length of feedings will increase engorgement; in the beginning, baby can not adequately empty the breasts in five or ten minutes.

• Use a hospital-grade electric breastpump to release some of the milk if you are becoming uncomfortably engorged and baby is not nursing well or often enough. This will soften the areola and allow baby to latch-on more efficiently and thus empty your breasts. Or gently use hand expression to release some milk. Express only enough milk to make you feel more comfortable. Expressing too much milk may stimulate the production of more milk. Remember, the production of milk works on the supply and demand principle.

• Soak your breasts in a warm shower just before expressing your milk or feeding your baby. Direct the shower spray from the top of your breast toward your nipple as you massage your breasts. This warmth helps trigger your milk ejection reflex, which gets the milk flowing more quickly when you begin to pump or baby begins to feed. Other ways to apply warmth and moisture to your breasts include leaning over a basin of warm water (gravity will help you express milk in this position) or applying warm compresses to your breasts.

• If baby is unable to nurse well, you need to pump your milk with an electric pump every 2 to 3 hours, to prevent problems with engorgement and to keep your milk production up. Basically, do whatever you need to do to get your milk out of your breasts. Frequent emptying of the breasts in the early stages of lactation will help you have a good milk supply in the weeks and months to come.

• Above all, don't stop breastfeeding. Unrelieved engorgement can lead to a breast infection, and a baby who nurses well can empty the breasts more efficiently than any pump.

• Between feedings, apply cold compresses to your breasts to relieve the pain and reduce swelling. Wrap small plastic bags filled with crushed ice in a lightweight dishtowel. (Crushed ice is less heavy on tender breasts-or try bags of frozen vegetables.)

• Wear a loose fitting bra. Avoid bras that are too tight and/or that compress the lower part of your breast against your body. This traps milk and sets you up for engorgement and possible mastitis.

• Rest, rest, rest! Lie down with your baby and nurse and nap together. There's something magical about the way rest relieves engorgement.

• What about using cabbage leaves to treat engorgement. So far, controlled studies have shown no benefit to this treatment over the standard treatments listed above. Yet some mothers find this works very well--and it's easier than trying to balance ice packs on your chest. Use clean cabbage leaves. Make a hole for the nipple and tuck them into your bra for twenty to thirty minutes. Repeat two or three times a day until engorgement is relieved.

If you have enjoyed weeks of trouble-free breastfeeding and then suddenly become engorged, take this as a signal that something is interfering with the balance between your milk supply and baby's demand: baby is going too long between feedings, isn't nursing well, or stress is affecting your nursing pattern or your milk ejection reflex. Veteran breastfeeding mothers take engorgement as a cue to take a few days off from other responsibilities to reconnect with baby. They increase the frequency and duration of feedings and soon resettle into a comfortable breastfeeding pattern.