Nipple stimulation

After birth, a rapid drop in progesterone level initially triggers lactation through reversal of inhibitory effects on prolactin (Fig. 44-2). Nipple stimulation then enables lactation to continue once established. During lactation, ineffective removal of milk from the breast, trauma, and skin breaks may lead to problems such as milk stasis, nipple pain, and mastitis.12 Additionally, some women have difficultly initiating lactation due to improper technique and/or activity of inhibitors such as dopamine (Fig. 44-2). 

Once the cervix has been ripened, or in patients who present with a favorable, soft cervix, labor induction can proceed with IV oxytocin (Pitocin ). This is a synthesized form of the same peptide composed of nine amino acids that is synthesized by the hypothalamus and secreted by the posterior pituitary. Although it will cause contractions beyond the late second trimester of pregnancy, these contractions do not always lead to labor. Labor also can be initiated or augmented by rupture of the amniotic and chorionic membranes, which is thought to up-regulate oxytocin receptors on the uterus and release prostaglandins. Nipple stimulation causes the increased release of oxytocin from the posterior pituitary and can be used to initiate corrtractions as well. 

There are a number of nonpharmacologic methods for cervical ripening. Castor oil, hot baths, sexual intercourse, and nipple stimulation all have been recommended for labor induction. However, there is minimal evidence to support the efficacy of these methods. The use of a Foley catheter placed in an unfavorable cervix for ripening has been found as effective as prostaglandin E2. A safe and inexpensive method, membrane stripping, is particularly of value. ... 

Declining serum prolactin concentrations cause a decrease in or cessation of lactation, and this can be problematic, as well as distressing, for mothers who desire to breast-feed their infants. Relactation is the process of increasing the breast milk supply for such women. Lactation also can be induced in women who have not recently delivered a baby, such as adoptive mothers. The mainstay of therapy for this condition involves nipple stimulation either by the infant s nursing or by pumping of the breast with a mechanical pump or the hand. One small study showed that a substance in beer and nonalcoholic beer can stimulate prolactin secretion and thus increase milk production. ... 

Prolactin Prolactin is an anterior pituitary hormone which induces milk secretion from the breasts of lactating women. Nipple stimulation promotes prolactin release and dopamine inhibits prolactin release. 

Other actions of estrogen include fluid retention, protein anabolism, thinning of the cervical mucus, and the inhibition or facilitation of ovulation. Estrogens contribute to the conservation of calcium and phosphorus, the growth of pubic and axillary hair, and pigmentation of the breast nipples and genitals. Estrogens also stimulate contraction of the fallopian tubes (which promotes movement of the ovum), modify the physical and chemical properties of the cervical mucus, and restore the endometrium after menstruation. 

Gonzalez-Mariscal, G., Chirino, R. and Hudson, R. (1994) Prolactin stimulates emission of nipple pheromone in ovariectomized New Zealand white rabbits. Biol. Reprod. 50, 373-376. 

Fos-like immunoreactivity in the MPOA and lateral preoptic area (LPOA) is associated with maternal behavior in both virgin female rats exposed to pups and lactating postpartum females (Numan and Numan, 1992). The observed induction of fos activity in the POA is likely partially due to the receipt of olfactory and ventral tactile and suckling-related sensory stimulation from pups. The POA also receives suckling-related sensory data related to lactation. However, because maternal behavior occurs in females who have been thelectomized (nipple removal) or olfactory bul-bectomized, a population of POA output cells exists that is essential for the performance of maternal duties in the absence of the usual sensory inputs (Numan, 1994). 

It also stimulates the development of skin pigmentation particularly in the region of the nipples and areolae and in the genital regions. 

Oxytocin is reflexly released from the pituitary following suckling (also by manual stimulation of the nipple) and causes almost immediate contraction of the myoepithelium of the breast it can be used to enhance milk ejection (nasal spray). The only other clinically important effect is on the blood pressure, which may fall if an overdose is given. 

The primary stimulus for oxytocin release is suclding. Stimulation of tactile receptors located around the nipples of the breasts initiates an action potential that propagates along afferent nerve fibers through the spinal cord and mid-bram to the hypothalamus. The cell bodies in the paraventricular nucleus are then stimulated, resulting in the episodic release of oxytocin. Stretch receptors in the uterus and possibly in the vaginal mucosa may also initiate action potentials in afferent nerve fibers that ultimately stimulate the release of oxytocin from the neurohypophysis. Estrogens enhance the response of oxytocin to these stimuli. The influence of other parts of the brain on the release of oxytocin has been reported emotional stress, for instance, inhibits lactation. 

Of course there are other chemicals in the body s Action/Reaction Factor closet that positively regulate prolactin. The major ones are GnRH, TRH (thyroid Releasing Hormone) and VIP (Vasoactive Intestinal Polypeptide). By the way, hyper-stimulation of the nipples may have a stimulatory effect upon prolactin release as well. But that is one we will leave alone. 

If increase in y causes a change in x, which tends to increase y, feedback is said to be positive in other words, a further signal output is evoked by the response it induces or provokes. This is intrinsically an unstable system, but there are physiologic situations where such control is valuable. In the positive feedback situation, the signal output will continue until no further response is required. Suckling provides an example stimulation of nipple receptors by the suckling child provokes an increased oxytocin release from the posterior pituitary with a corresponding increase in milk flow. Removal of the stimulus causes cessation of oxytocin release. 

The warm touch of the breast on the baby s cheek will stimulate the natural rooting reaction, causing it to turn its head in the direction of the touch and to begin sucking motions with its mouth. Stroke the cheek nearest the nipple, and the baby will turn toward it. (Never touch the cheek furthest from the nipple, as it will cause the baby to turn its head in that direction—away from the nipple.) If necessary to get the baby started, press a little milk onto its lips. The baby should grasp most of the nipple in its mouth, not merely the outer tip. 

Traditional Medicine. Flower historically considered vulnerary, antiseptic, styptic externally used as lotion or ointment for bums and scalds (1st degree), bruises, cuts, rashes, sore nipples internally for stomach ailments gastric and duodenal ulcers, and jaundice (foster wren). Herb and its preparations reportedly used to stimulate circulation, pro-... 

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