|
Lactation |
|
|
Delivery of the baby, with the accompanying drop in maternal estrogen
and progesterone levels, initiates a sequence of events that leads to
production of milk.
The alveoli of the breast secrete milk into the glandular lumen. Each alveolus is surrounded by smooth muscle that, when contracted, squeezes the milk out of the alveolus and into the duct system that ultimately leads to the nipple. This milk ejection system, also known as "letting down" is triggered by the release of maternal oxytocin from the anterior pituitary. Suckling of the nipple stimulates this response, as can a variety of other stimuli (e.g. sound of a crying baby).
Each act of nursing reinforces lactation, in part by stimulating the release of prolactin. Reducing the frequency of nursing usually leads to decrease in milk production and (if infrequent enough), cessation of lactation. Some women who continue to regularly breast feed will usually continue to produce milk as long as they nurse (even years). Others will notice a gradual decline in quantity of milk over time.
Women who do not breast feed will notice breast engorgement during the first few days following delivery. They will produce some milk and may experience some breast discomfort. So long as the breasts are not stimulated (by emptying the milk or stimulating the nipples), this engorgement will gradually resolve and milk secretion will stop. Wearing a well-fitting bra, the use of ice packs, and avoiding any manual stimulation will facilitate this resolution. Medication to help "dry up" the breasts has been used in the past by some, but concerns about side effects have limited their usefulness. Bromcriptine and other prolactin-suppressing medications have been associated with hypertension, stroke and seizures. Estrogen increases the risk of thromboembolism. Most physicians usually recommend conservative measures to treat this self-limited problem.
Colostrum
Within a day or two of delivery, a small amount of dark-yellow liquid
can be expressed from the breasts. This is the precursor of milk, is
rich in minerals and protein, but has less sugar and fat than mature
milk. It also contains antibodies that are helpful in protecting the
newborn.
Milk
After several days, the colostrum will gradually become more white in
color as the alveoli change to the production of mature breast milk.
Mature milk has the same mineral and protein content as colostrum, but
has increased amounts of fat and carbohydrates. Once well established,
most nursing mothers will produce at least 600 ml of milk per day.
Benefits of Breast Feeding
It should be obvious that breast milk is ideally formulated for the
newborn. Studies have confirmed a reduction in certain types of
infection and developmental abnormalities among breast-fed infants, and
suggest a possible enhancement of cognitive development. Breastfeeding
is convenient, free, and provides considerable satisfaction to most
mothers and babies. Because lactation requires up to 1500 calories per
day just to produce the milk, it can facilitate return to pre-pregnancy
weight levels.
Drawbacks to
Breast Feeding
While breast milk is the undisputed best for newborns, modern formulas
and breast milk substitutes do a very good job of providing a balanced
nutrition. Some women experience difficulty in providing enough milk.
Some babies prefer the quick satisfaction of a bottle over the slower
and more energy-consuming process of suckling. Some inverted nipples
never will evert sufficiently for a newborn to latch on. Women who work
may find it difficult to arrange their schedule to provide for nursing
with the frequency that women at home are able to achieve. Nursing does
not allow for the woman's partner to feed the baby in the middle of the
night. This leads to an aggravation of the sleep deprivation that most
postpartum women experience. Some women experience repetitive breast
infections that interfere with their other responsibilities.
Contraindications to Breast Feeding
- Galactosemia in the newborn
- Maternal HIV
- Untreated tuberculosis
- Illegal drug users
- Excessive alcohol intake
- Active herpes on the breast
- Hepatitis B carriers (unless the infant is treated with hyperimmune globulin)
- Cytomegalovirus
- Maternal exposure to radioisotopes of iodine, gallium, technetium, indium and sodium
For these reasons, there is no single best approach to infant nutrition for all women under all circumstances. I encourage women to breastfeed, even if only for a short time, for the benefits it provides to newborn infants. If breastfeeding were the only important issue in life, I suppose I would would be fanatical about insisting that all women breastfeed. But life is complex and other issues are also important. Be a helpful resource to your patient and support whatever approach will best meet her needs and the needs of her family. Useful guidance in these areas can be found at:
- American Academy of Pediatrics (www.aap.org)
- La Leche League International (www.lalecheleague.org)
Birth Control Pills
The American Academy of Pediatricians has determined that oral
contraceptive pills are compatible with breastfeeding. Unquestionably,
some of the hormone gets into the breast milk and is taken in by the
newborn. But the amount of hormone ingested is so tiny as to be
inconsequential.
Combined estrogen-progestin pills (and their cousins, the contraceptive patch and ring) are highly effective, but may diminish the quantity of breast milk secreted. Most women taking these OCPs don't notice any decrease. If they do, the decrease is small enough to be unimportant and does not interfere with the newborn getting enough to eat. Occasionally, there is so much reduction in milk supply that it creates a problem. In such cases, stopping the OCPs will usually resolve this problem.
Some obstetricians favor the use of progestin-only pills. These will not reduce milk production, but have a higher failure rate and break through bleeding rate than the combined estrogen-progestin pills.
Oral contraceptive pills are usually started around 6 weeks following delivery, but may be started as early as discharge from the hospital.
Other Medications
As a general rule,
medications
that are OK during pregnancy are OK while breastfeeding. Similarly,
medications that ought not be used during pregnancy should also not be
used while breastfeeding. Among the exceptions to these general rules
are oral contraceptive pills.
Care of the Breasts
Little other than normal cleanliness is required to care for the
lactating breast. Dried milk on the nipple can cause some irritation, so
rinsing the nipple with warm water (and a very mild soap, if needed) before
and after nursing can help prevent that occurrence. If you use any soap,
be sure to rinse it off quite well before initiating nursing.
Sore nipples are common in the first few days of nursing and gradually resolve. Sore nipples after that (or severe pain) may indicate cracked nipples (which predispose toward mastitis), or suboptimal feeding positions.
The development of severe pain or high fever may indicate mastitis, requiring prompt antibiotic treatment.
Common Questions
How often should a baby nurse?
- 8 or more times in 24 hours for a newborn.
- More often than the usual Q3 to Q4 hour schedule for bottle-fed babies
- During the night, the interval may stretch out to 4-5 hours, if the baby is sleeping.
- During the day, make sure the baby nurses at least every 3 hours, even if sleeping.
How long should the woman nurse?
- 10 to 15 minutes on each breast
- If the baby won't feed that long, use shorter intervals on both breasts
How do you know if the baby is getting enough to eat?
- The baby should urinate 6 or more times a day.
- The baby should pass a yellowish stool 4 or more times a day
- The baby usually will fall asleep will nursing on the second breast
- Once milk supply is well established, the baby will gain about an ounce a day for the first few months.
How do you know if the baby is hungry?
- By the time the baby starts crying, it has been hungry for a long time.
- Increased arousal, rooting movements, thumb or hand sucking, lip smacking.
Is use of a pacifier OK?
- Yes, although early use (first week) may interfere with good nursing habits.
How about a bottle every now and then?
- Yes, that's OK. Establishing the baby's tolerance for an occasional bottle increases the options for dealing with unexpected illness, father's participation, return to work, and other issues.
- Ideally, the occasional bottle is introduced after three or four weeks so that the basic breastfeeding pattern is well-established. If necessary, though, it can be started right away.