Nutrition, Lactation and Exclusive Breastfeeding

Nutrition refers to intake of food necessary for optimal growth, function, and health.

A nutrient-rich maternal diet before and during pregnancy is associated with improved fetal health, more appropriate birth weight, and increased rates of maternal and infant survival.

In developing countries, maternal undernutrition is a major factor contributing to adverse pregnancy outcomes.

While in developed countries overnutrition is the problem

Undernutrition, overnutrition, and poor diet composition negatively impact fetoplacental growth and metabolic patterns, having adverse later life metabolic effects for the offspring.

Pregnancy and lactation are associated with major metabolic and physiologic changes in the mother.

Nutritional requirements increase to optimize both maternal adaptation and fetal development.

Improving the mother’s diet before and during pregnancy reduces the risk of medical problems for her and her infant.

Studies have shown that there is need for supplementation of ferrous, folate, iodine, and calcium for all pregnancies.

There is good evidence for supplementation with vitamin C in pregnant women who smoke.

Pregnant women should be encouraged to eat a balanced diet rich in fresh or frozen fruits and vegetables, high-quality carbohydrates including whole grains, and with a good mix of proteins from beans, lean meats, fish, and seafood.

Their diet should be low in added sugar, red meat, and processed foods.

During pregnancy, maternal weight gain affects fetal growth.

Small neonate size at birth is attributable to poor growth and shortened gestation, and the most unfavorable outcomes occur in the most immature infants.

Low rate of pregnancy weight gain is associated with increased risk of preterm birth, whereas low second- or third-trimester weight gain has been shown to be associated with spontaneous preterm delivery risk.

Women with low prepregnancy BMI are at increased risk for preterm birth and intrauterine growth retardation (IUGR)- only if they fail to gain adequate weight.

Appropriate GWG within target ranges can help improve maternal and fetal health.

Inadequate GWG has been associated with low birth weight (<2500 g) and gaining more weight than recommended with high birth weight (>4000 g) and postpartum weight retention.

Breast milk is the preferred source of nutrients for newborn infants

Lactation

It is the process by which milk is synthesized and secreted from the mammary glands of the postpartum female breast in response to an infant sucking at the nipple.

It is a hallmark feature of female mammals.

It is under endocrine control.

The two main hormones involved are prolactin and oxytocin.

Action of Prolactin in Lactation

Prolactin is necessary for the secretion of milk by the cells of the alveoli.

The level of prolactin in the blood increases markedly during pregnancy and stimulates the growth and development of the mammary tissue, in preparation for the production of milk.

However, milk is not secreted then (during pregnancy), because progesterone and estrogen block this action of prolactin.

After delivery, levels of progesterone and estrogen fall rapidly, prolactin is no longer blocked, and milk secretion begins.

During suckling, the level of prolactin in the blood increases, and stimulates production of milk by the alveoli.

The prolactin level is highest about 30 minutes after the beginning of the feed, so its most important effect is to make milk for the next feed

The more a baby suckles and stimulates the nipple, the more prolactin is produced, and the more milk is produced. This effect is particularly important at the time when lactation is becoming established.

Although prolactin is still necessary for milk production, after a few weeks there is not a close relationship between the amount of prolactin and the amount of milk produced. However, if the mother stops breastfeeding, milk secretion may stop too – then the milk will dry up

More prolactin is produced at night, so breastfeeding at night is especially helpful for keeping up the milk supply.

Prolactin seems to make a mother feel relaxed and sleepy, so she usually rests well even if she breastfeeds at night.

Suckling affects the release of other pituitary hormones, including gonadotrophin releasing hormone (GnRH), follicle stimulating hormone, and luteinising hormone, which results in suppression of ovulation and menstruation. Therefore, frequent breastfeeding can help to delay a new pregnancy. Breastfeeding at night is important to ensure this effect

Oxytocin Action

Oxytocin makes the myoepithelial cells around the alveoli contract. This makes the milk, which has collected in the alveoli, flow along and fill the ducts. It makes the milk that is already in the breast flow for the current feed.

The oxytocin reflex is also called the “letdown reflex” or the “milk ejection reflex”. Oxytocin is produced more quickly than prolactin. Oxytocin starts working when a mother expects a feed as well as when the baby is suckling. The reflex becomes conditioned to the mother's sensations and feelings, such as touching, smelling or seeing her baby, or hearing her baby cry, or thinking lovingly about him or her.

Severe pain or emotionally upset, oxytocin reflex may become inhibited.

It is important to understand the oxytocin reflex, because it explains why the mother and baby should be kept together and why they should have skin-to-skin contact.

Oxytocin makes a mother's uterus contract after delivery and helps to reduce bleeding. The contractions can cause severe uterine pain when a baby suckles during the first few days.

There are four stages of lactation:

1. Mammogenesis (growth of the breasts)
2. Lactogenesis (the functional change of the breasts so that they can secrete milk)
3. Galactopoiesis (maintaining the production of milk)
4. Involution (the termination of milk production).

Mammogenesis

Mammogenesis is the process of growth and development of the mammary gland in preparation for milk production.

This process begins when the mammary gland is exposed to estrogen at puberty and is completed during the third trimester of pregnancy

Before pregnancy, the breast is predominantly adipose tissue without extensive glandular or ductal development.

Under the influence of uninterrupted and rising concentrations of estrogen, progesterone, and prolactin during pregnancy, the breast increases in water, electrolyte, and fat content to about 0.338kg per breast

There is also a marked increase in the vascular supply to the breast; the dilated subcutaneous mammary veins become prominent, and the blood flow increases twofold.

Size and pigmentation of the nipples also increase under the influence of rising estrogen concentrations.

The sebaceous glands of Montgomery on the periphery of the areolae greatly enlarge; during lactation, they produce a secretion important for nipple conditioning and lubrication.

Lactogenesis, or the process of changes to the mammary glands to begin producing milk, begins during the late stages of pregnancy.

It requires 2–5 days in the human being, this is the length of time necessary for complete secretory maturation of acinar epithelium.

The inhibition of lactogenesis before delivery appears to be a consequence of high circulating levels of progesterone, which competitively inhibits the binding of cortisol to an intracellular receptor.

This prevents cortisol from acting synergistically with prolactin to initiate milk production.

Lactogenesis

The rapid fall in progesterone mainly, estrogen, and human placental lactogen levels after deliver allows cortisol binding to occur and lactogenesis to proceed. Administration of large doses of progesterone in the immediate postpartum period inhibits milk production.

However, once the secretory transformation of the acinar epithelium is completed, sex steroids are ineffective in halting lactogenesis.

Galactopoiesis

Galactopoiesis is the maintenance of milk production once it has been established.

The single most important factor in successful galactopoiesis is regular and frequent milk removal from the mammary gland.

Milk removal stimulates further milk secretion by at least three mechanisms.

First: Regular suckling promotes the regular synthesis and release of both prolactin and oxytocin, which are necessary for continued milk secretion.

Secondly: Regular emptying of the breasts of milk. The breast has the capacity to store milk for a maximum of 48 hours before there is a substantial decrease in production

Increased intramammary pressure resulting from distention of the mammary ducts and alveoli with stored milk which occurs in absence of regular emptying leads to reduced milk production, this is caused by the diminished stimulation of the glandular epithelium by prolactin and vascular stasis.

Blood flow to the mammary glands is also significantly reduced by this increased intramammary pressure, which diminishes the nutrient and hormonal supply necessary for milk production.

Thirdly: The amount of milk produced daily is fairly closely related to the demand (i.e. the amount of milk removed the previous day), as long as the nutritional and hormonal requirements are met.

Normal levels of prolactin (5–20 ng/ml), with surges of prolactin and oxytocin at the time of suckling, are also necessary for the maintenance of normal milk production.

Colostrum

Colostrum is secreted during the first 48–72 hours postpartum. Only a small volume of colostrum is produced—approximately 3 ounces in a 24-hour period—but it is sufficient for the newborn in the first few days of life.

Colostrum is rich with immunoglobulins, which confer gastrointestinal, and also likely systemic, immunity as the newborn adjusts to a nonsterile environment.

Transitional and Mature Milk

After about the third postpartum day, the mother secretes transitional milk that represents an intermediate between mature milk and colostrum. This is followed by mature milk from approximately postpartum day 10.

Mature milk changes from the beginning to the end of a feeding. The early milk, called foremilk, is watery, translucent, and rich in lactose and protein. Its purpose is to quench the infant’s thirst. Hindmilk is delivered toward the end of a feeding. It is opaque, creamy, and rich in fat, and serves to satisfy the infant’s appetite.

Exclusive breastfeeding means that the infant receives only breast milk. No other liquids or solids are given – not even water

WHO recommends that Infants should be exclusively breastfed – i.e. receive only breast milk –for the first six months of life to achieve optimal growth, development and health.

After six months, the baby should start on complementary foods. Mothers who are not infected with HIV should breastfeed until the infant is two years or older.

HIV infection may be transmitted through breast milk from mother to child and this risk approach 5-15% in the absence of any intervention.

Breast milk substitute has the benefit of zero HIV transmission but carries with it the risk of increased morbidity and mortality from malnutrition, diarrhea and pneumonia.

It is recommended that mothers of HIV exposed infants breastfeed their babies exclusively for the first six (6) months of life (especially in developing countries).

Complementary feeds should be introduced at 6 months in addition to breast milk

Breastfeeding complemented by household foods should be continued till 12 months, after which child should be weaned off breast milk.

Maternal

• Burns extra calories, it helps mother to lose pregnancy weight faster
• It releases the hormone oxytocin, which helps the uterus return to its pre-pregnancy size and may reduce uterine bleeding after birth
• Breastfeeding also lowers the risk of breast and ovarian cancer.
• It may lower maternal risk of osteoporosis, too.
• Frequent and exclusive breastfeeding can delay the return of fertility through lactational amenorrhea, though breastfeeding is an imperfect means of birth control

Baby

• Provides the ideal nutrition for infants
• It is more easily digested than infant formula
• Contains antibodies that help your baby fight off viruses and bacteria
• Lowers your baby's risk of having asthma or allergies.
• Has been linked to higher IQ scores in later childhood
• The physical closeness, skin-to-skin touching, and eye contact all help the baby bond with the mother and feel secure
• Babies exclusively breastfed for 6 months have fewer ear infections, respiratory illnesses, and bouts of diarrhea.
• Plays a role in the prevention of SIDS (sudden infant death syndrome).
• More likely to gain the right amount of weight as they grow rather than become overweight children.

Maternal

• Mother on chemotherapy or recent/current use of radioactive agents
• Mother with human T-cell lymphotrophic viral infection, untreated brucellosis
• Mother having untreated (not yet yet sputum negative) open tuberculosis (but is still expressing breast milk and can feed)
• Alcohol consumption
• Drug Addiction
• Mother with suspected/diagnosed HIV

Baby

• Infants with classic galactosemia (galactose 1-phosphate uridyltransferase deficiency)- Absolute contraindication
• Mothers who are infected with human immunodeficiency virus (HIV).

Breast milk is always fresh, perfectly clean, just the right temperature, and is the healthy choice at the least cost.