allergen A microscopic particle of a substance that can cause an allergic reaction in someone whose immune system is sensitized.

alveoli Small grapelike clusters of cells in the breast where milk is produced.

amenorrhea A term for the halting of the menstrual cycle.

anesthesia A drug administered to block pain.

antibody Cells in the body that fight foreign cells (e.g., bacteria, fungi, and viruses).

areola The circle of dark breast tissue surrounding the nipple.

aromatherapy The use of scented oils, candles, or other items to influence a person's mental state.

attachment/bonding The process of forming a strong emotional connection with another person.

baby blues The short-term feeling of sadness resulting from hormonal imbalance and stress immediately following birth or abrupt weaning from the breast.

babywearing The practice of carrying an infant on your body, usually in a sling.

bilirubin A by-product of the breakdown of excess red blood cells. Extremely high levels can cause brain damage.

birth plan An outline of your desired birthing experience.

breast abscess An infection of the breast marked by pain, swelling, and pus.

breastfeeding The natural act of feeding a child human milk from the mother's breasts.

breast lobes The 15 to 25 internal divisions of the breast, like the sections of an orange.

breast lobules The 20 to 40 divisions of each breast lobe that contain milk-producing cells.

breast pump A mechanical device for expression of breastmilk.

breast shells Domelike plastic rings used to evert nipples.

Caesarean section Birthing in which the infant is removed surgically through the mother's abdomen.

candida See thrush.

casein The protein in milk that forms hard cottage-cheese-like curds in the stomach.

cholecystokinin (CCK) A hormone released from the lining of the stomach that induces a feeling of satisfaction in the brain.

cleft lip/cleft palate A condition in which an infant's lips do not grow together completely in the womb. Cleft palate refers to a similar condition affecting the roof of a child's mouth.

cluster or bunch feeding Frequent, eager nursings with little time between sessions.

co-bedding The centuries-old practice of sleeping with your baby. Also called the family bed.

colic A catchall term used to describe any number of conditions in babies whose symptoms include crying continuously for three or more hours, three or more times per week, for three or more weeks.

colostrum Supermilk produced by mothers in the first few days after birthing.

demand feeding The practice of breastfeeding a baby when she's hungry, as opposed to a predetermined schedule.

diastasis A condition in which the vertical abdominal muscles separate during labor.

docosahexaenoic acid (DHA) An important fat that helps build brain tissue in babies.

doll-eye maneuver Bringing your baby to an upright position so that her eyes will open, like the eyes of toy dolls.

double pumping Using a specially fitted breast pump to express milk from both breasts simultaneously.

doula A professional labor assistant.

eczema A skin condition characterized by dry, patchy skin.

engorgement The enlargement of a woman's breasts caused by the onset of milk production or the buildup of milk following abrupt weaning.

estrogen The primary female sex hormone; produced mainly in the ovaries.

evert To make protrude; the opposite of invert.

exclusive breastfeeding The practice of feeding a baby nothing but breastmilk.

extended nursing Breastfeeding children who are beyond one year of age.

Family and Medical Leave Act (FMLA) FMLA entitles eligible employees to take up to twelve weeks of unpaid, job-protected leave within a twelvemonth period for specified family and medical reasons.

family bed See co-bedding.

finger feeding Allowing an infant to suckle on a clean adult finger while breastmilk is introduced into the mouth through a syringe or supplemental feeding tube.

flow rate The speed at which milk flows through a bottle nipple.

foremilk The first milk baby receives during a nursing session. Foremilk is low in fat and high in volume.

frenulum The thin strip of tissue that connects the bottom of the tongue to the floor of the mouth.

galactose One of the two sugars formed by the digestion of lactose.

galactosemia A hereditary condition in which a child cannot digest galactose.

gastroesophageal reflux (GER) A condition in which the muscular valve at the juncture of the stomach and throat allows stomach contents and acid into the esophagus, causing a painful, heartburn-like sensation.

gavage Feeding method in which a tube is inserted through a baby's mouth and into the stomach.

glucose A simple sugar.

hindmilk The breastmilk released after several minutes of nursing. Hindmilk is rich in fat and important nutrients.

hunger cues Signals that a baby is hungry. These typically include rooting, chewing on a fist, and crying.

hypoglycemia Low blood sugar.

hypothalamus A part of the brain that regulates many autonomic functions like body temperature and milk production.

hypothyroidism A condition in which the thyroid gland is underactive, resulting in many symptoms, including a diminished milk supply.

immune system The body's protection against disease.

infant formula Any of the artificial liquid foods designed for babies. Infant formulas are usually based on animal milk or soy.

inverted nipples Nipples that do not protrude from the breast when stimulated.

involute The process by which the uterus contracts following childbirth, returning to its prepregnancy size.

jaundice A typical condition of newborns in which the child is excessively sleepy and exhibits yellowing of her skin and the whites of her eyes. Jaundice is caused by an excess of red blood cells.

Kegel An exercise for tightening and strengthening the muscles of the perineal floor.

Lactaid A supplemental feeding device worn by the mother. A reservoir of milk is worn around the mother's neck and a tube from that supply is inserted into the baby's mouth as she nurses at the breast.

lactation The medical term for the production of milk.

lactation consultant A board-certified professional specializing in the breast and breastfeeding.

lactogenesis The onset of milk production.

lactose Milk sugar.

latch The connection between baby and breast.

letdown reflex See milk ejection reflex.

lochia The menses-like flow of blood from the vagina following birthing.

lumpectomy The removal of a growth or tumor without destruction of surrounding tissues.

manual expression Removing milk from the breast using the hand.

mastectomy Surgical removal of all or part of the breast.

mastitis An infection of the breast characterized by flu-like symptoms and swelling, redness, and tenderness of the affected breast.

mature milk Breastmilk produced after five days postpartum.

meconium Greenish-black, tarlike stool present in newborns.

milk bank Storage, preparation, and distribution facilities for donated human milk.

milk ducts The channels connecting the alveoli to the milk sinuses.

milk ejection reflex The release of breastmilk from the milk-producing cells of the breast, caused by muscular contractions in response to oxytocin.

milk sinuses The area beneath the areola that must be compressed to force milk through the nipple.

Montgomery glands The small bumps on the areolas of a lactating woman that produce a substance that keeps the nipples clean and lubricated.

mylenization The covering of nerve fibers with an insulating layer of fat.

neonatal intensive care unit (NICU) Intensive care unit for infants born premature, or others suffering from neonatal illnesses, diseases, or disorders.

nipple shields Thin plastic protectors that fit over a mother's nipples as she nurses her child.

nursing strike A baby's abrupt refusal to breastfeed due to some interfering factor like teething pain, a stuffy nose, or even Mom's new perfume.

orthodontic nipple Bottle nipples that are designed to help a baby's oral cavity and teeth develop properly.

oxytocin The hormone responsible for the milk ejection reflex.

perineum The connective tissue between the vagina and the anus.

phenylalanine An important amino acid.

phenylketonuria (PKU) An inherited disorder in which the body is unable to properly utilize phenylalanine.

phototherapy The use of special lights in the treatment of newborn jaundice and seasonal affective disorder.

pituitary gland The body's master gland, which produces many hormones, including prolactin and oxytocin.

plugged duct A condition in which a milk duct becomes clogged, resulting in a hard spot in the breast with accompanying tenderness.

postpartum Following labor and delivery.

postpartum depression (PPD) Feelings of despair or hopelessness following the birth of a baby and lasting longer than two weeks.

postpartum psychosis A rare disorder of mothers characterized by hallucinations, delusions, and extreme confusion.

premature infant A child born before 36 weeks’ gestation.

preterm milk Breastmilk produced by the mother of a premature infant. Preterm milk is especially high in fats, proteins, and sugars.

progesterone Along with estrogen, progesterone is one of the two primary female hormones regulating fertility.

progestin The synthetic version of progesterone.

prolactin The hormone responsible for milk production.

relactating Re-establishing breastmilk production after it has been stopped.

seasonal affective disorder (SAD) A physiological condition of depression caused by a lack of sunlight and activity. SAD is most common in northern latitudes.

sleep apnea A condition in which a person stops breathing during sleep, often occurring many times throughout the night and requiring the sufferer to awaken in order to begin breathing again.

sleep/wake cycle The states of consciousness and arousability. They include: quiet alert, active alert, crying, drowsiness, active sleep, and deep sleep.

sudden infant death syndrome (SIDS) The unexpected death of a child under age one in which there is no explainable cause of death. Also called crib death.

supplemental feeding Feeding done in addition to or in place of breastfeeding.

swaddling Wrapping a baby snugly in a blanket. The practice of swaddling helps a young infant to feel secure and warm.

tandem nursing Breastfeeding more than one child.

thrush A yeast infection of a baby's mouth and, subsequently, the mother's nipples.

tongue thrust The reflexive ejection of anything placed in a baby's mouth.

transitional milk The mix of colostrum and mature milk.

weaning The process of transitioning a child away from the breast.

wet nurse A woman who is paid to breastfeed a child other than her own.

yeast infection Any infection caused by yeast fungi. See thrush.