SIMMONDS DISEASE:
Simmonds' disease (also Simmonds' syndrome) refers to panhypopituitarism caused by the destruction of the pituitary gland due to infiltrative processes (e.g. lymphocytic), tumours (pituitary adenomas or craniopharyngiomas) or trauma (cranial injury or following surgery).
Sheehan's syndrome is a sub-classification of Simmond's disease occurring specifically in the peripartum period.
EPONYM
It was first described by Morris Simmonds when a patient presented with 'fatal cachexia', although his patient went on to live for 11 more years. [1][2]
SYMPTOMS
Although cachexia may be present, the disease is characterised by symptoms due to decreased gonadal, thyroidal and adrenal function. These include:
amenorrhoea or oligomenorrhoea, impotence, loss of libido
tiredness, hypotension
waxy skin, loss of body hair
HYPOPITUTARISM
Hypopituitarism is a medical term describing the deficiency (hypo) of one or more hormones of the pituitary gland. The hypothalamus regulates pituitary secretion by the production of releasing hormones and posterior pituitary hormones and hence its dysfunction can also lead to hypopituitarism.
In endocrinology, deficiency of one or multiple hormones of the anterior pituitary is generally referred to as hypopituitarism, while deficiency of the posterior lobe generally only leads to central diabetes insipidus. The deficiency of all anterior pituitary hormones is termed panhypopituitarism.
PHYSIOLOGY
The hormones of the anterior pituitary include 2 proteins, 3 glycoproteins and a polypeptide:
prolactin (PRL) - stimulates milk production in the breast
growth hormone (GH) - growth and glucose homeostasis
luteinizing hormone (LH) - menstrual cycle and reproduction
follicle stimulating hormone (FSH) - same
thyroid stimulating hormone (TSH) - stimulates thyroxine production in the thyroid
adrenocorticotropic hormone (ACTH) - stimulates glucocorticoid production in the adrenal gland
These hormones are secreted in individually characteristic pulsatile patterns, often with distinct circadian rhythm, rather than at steady rates throughout 24 hours.
The posterior pituitary is the site of release of the nonapeptide hormones antidiuretic hormone (ADH) and oxytocin, the former regulating plasma osmolarity and the latter regulating uterine contractions during childbirth as well milk ejection from the breasts.
Multiple hormone deficiencies:
Deficiency of a single pituitary hormone occurs less commonly than deficiency of more than one hormone. Sometimes referred to as progressive pituitary hormone deficiency or partial hypopituitarism, there is usually a predictable order of hormone loss.
Generally, growth hormone is lost first, then luteinizing hormone deficiency follows. The loss of follicle-stimulating hormone, thyroid stimulating hormone and adrenocorticotopic hormones follow much later. The progressive loss of pituitary hormone secretion is usually a slow process, which can occur over a period of months or years. Hypopituitarism does occasionally start suddenly with rapid onset of symptoms
Most people with hypopituitarism lack growth hormone as well as one or more others. As for the posterior pituitary, antidiuretic hormone deficiency is the main problem, while oxytocin deficiency rarely causes clinically significant problems.
CASUSES
Hypopituitarism and panhypopituitarism can be congenital or acquired. A partial list of causes and forms:
Congenital hypopituitarism
Hypoplasia of the pituitary
Isolated idiopathic congenital hypopituitarism
Associated with other congenital syndromes and birth defects
Septo-optic dysplasia
Holoprosencephaly
Chromosome 22 deletion syndrome
Rapaport syndrome
Single gene defect forms of anterior pituitary hormone deficiency
Acquired hypopituitarism (Simmonds' disease)
trauma (e.g., skull base fracture)
surgery (e.g., removal of pituitary neoplasm)
tumor - secretory and non-secretory (20%) pituitary or hypothalamic neoplasms, cause hypopituitarism by compressing the remaining tissue
inflammation (e.g. sarcoidosis or autoimmune hypophysitis)
radiation (e.g., after cranial irradiation for childhood leukemia)
shock
(Sheehan's syndrome is hypopituitarism after heavy bleeding in childbirth)
hemochromatosis
other diseases.
DIAGNOSIS
Hypopituitarism may come to medical attention by symptoms or features of pituitary hormone deficiency (e.g., poor growth, hypoglycemia, micropenis, delayed puberty, polyuria, impaired libido, fatigue, and many others), or because the physician has diagnosed one of the many disorders and conditions associated with hypopituitarism listed above and tests for it. A provocative test (triple bolus test) measures the secretory response of the pituitary to a stimulus (other hormones, drugs, exercise, etc.) by measuring serum levels of the hormone involved.
REPLACEMENT THERAPY
Hypopituitarism and panhypopituitarism are treated by replacement of appropriate hormones. Since most of the anterior pituitary hormones are proteins or glycoproteins released in pulsatile patterns, whose functions are to induce secretion of smaller molecule hormones (thyroid hormones and steroids), it is simpler and less expensive for most purposes to simply replace the target gland hormones. There are a few exceptions, such as fertility induction.
GH is replaced with growth hormone.
TSH is replaced with thyroxine.
ACTH is usually replaced with hydrocortisone but any glucocorticoid may be used.
LH and FSH are most often replaced by supplying the appropriate sex steroids (e.g., testosterone or estrogen and progestin). Virtually all people who need T or E2 replacement for hypopituitarism rarely have spontaneous, effective spermatogenesis or follicular maturation. Both GnRH by subcutaneous pump and gonadotropins (Pergonal) by daily subcutaneous injections have been used effectively to induce fertility.
Prolactin is not usually replaced, as infant formula is readily available, simpler, and much cheaper.
ADH is replaced most commonly with oral, nasal, and sometimes intravenous or subcutaneous desmopressin.
Oxytocin is most important during labor and delivery at the end of pregnancy, and can be replaced in that circumstance by pitressin.
THE PITUTARY:
The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea that sits in a small, boney cavity (pituitary fossa) covered by a dural fold (sellar diaphragm) at the base of the brain. The pituitary fossa, in which the pituitary gland sits, is situated in the sphenoid bone in the middle cranial fossa at the base of the brain.
The pituitary gland secretes hormones regulating homeostasis, including trophic hormones that stimulate other endocrine glands. It is functionally connected to the hypothalamus by the median eminence. It also secretes hormones for sexual eminence and desires.
SECTIONS:
Located at the base of the brain, the pituitary is functionally linked to the hypothalamus. It is divided into two lobes: the anterior or front lobe (adenohypophysis) and the posterior or rear lobe (neurohypophysis).
Anterior pituitary (Adenohypophysis)
Main article: Anterior pituitary
The anterior lobe is derived from the oral ectoderm and is composed of glandular epithelium. The anterior pituitary is functionally linked to the hypothalamus via the hypophysial-portal vascular connection in the pituitary stalk. Through this vascular connection the hypothalamus integrates stimulatory and inhibitory central and peripheral signals to the five phenotypically distinct pituitary cell types.
The anterior pituitary synthesizes and secrets important endocrine hormones, such as ACTH, TSH, prolactin, growth hormone, endorphins, FSH, and LH. Most of these hormones are released from the anterior petuitary under the influence of hypothalamic hormones. The hypothalamic hormones travel to the anterior lobe by way of a special capillary system, called the hypothalamic-hypophyseal portal system.
The control of hormones from the anterior pituitary exerts a negative feedback loop. Their release is inhibited by increasing levels of hormones from the target gland on which they act.
Posterior pituitary (neurohypophysis)
Main article: Posterior pituitary
The posterior lobe is connected to a part of the brain called the hypothalamus via the infundibulum (or stalk), giving rise to the tuberoinfundibular pathway. Hormones are made in nerve cell bodies positioned in the hypothalamus, and these hormones are then transported down the nerve cell's axons to the posterior pituitary. Hypothalamic neurons fire such hormones, releasing them into the capillaries of the pituitary gland.
The hormones secreted by the posterior pituitary are
Oxytocin comes from the paraventricular nucleus in the Hypothalamus
Antidiuretic hormone (ADH, also known as vasopressin and AVP, arginine vasopressin), comes from the supraoptic nucleus in the Hypothalamus
Intermediate lobe
There is also an intermediate lobe in many animals. For instance in fish it is believed to control physiological colour change. In adult humans it is just a thin layer of cells between the anterior and posterior pituitary, nearly indistinguishable from the anterior lobe. The intermediate lobe produces melanocyte-stimulating hormone (MSH), although this function is often (imprecisely) attributed to the anterior pituitary.
Functions
The pituitary gland helps control the following body processes:
Growth
Blood pressure
Some aspects of pregnancy and childbirth
Breast milk production
Sex organ functions in both women and men
Thyroid gland function
The conversion of food into energy (metabolism)
Water and osmolarity regulation in the body.
Pathology
Disorders involving the pituitary gland include:Condition Direction Hormone
Acromegaly overproduction growth hormone
Growth hormone deficiency underproduction growth hormone
Syndrome of inappropriate antidiuretic hormone overproduction vasopressin
Diabetes insipidus underproduction vasopressin
Sheehan syndrome underproduction prolactin
Pituitary adenoma overproduction any pituitary hormone
Hypopituitarism underproduction any pituitary hormone
FUNCTIONS OF PITUTARY
Human development is the process of growing to maturity. In biological terms, this entails growth from a one-celled zygote to an adult human being.
Biological development
Development begins with fertilization, the process by which the male gamete, the sperm cell, and the female gamete, the oocyte, fuse to give rise to a diploid cell, the zygote.
In medicine, pregnancy is defined as beginning when a fertilized zygote becomes implanted in a woman's uterus. This occurs when the zygote then becomes embedded into the endometrium (lining of the uterus) where it forms a placenta, for the purpose of receiving essential nutrients through the uterus wall. The umbilical cord in a newborn child signifies the remnants of implantation.
The zygote undergoes rapid mitotic divisions with no significant growth (a process known as cleavage) and cellular differentiation, leading to development of an embryo.
Childbirth is the process in which the baby is born. It is considered by many to be the beginning of a person's life, where age is defined relative to this event in most cultures.
Growth is normally controlled and moderated by the Pituitary Gland, located at the base of the skull in humans.
Physical stages
Terms for stages of age-related physical development include, with their approximate age ranges:
Zygote, the point of conception, fertilization
Blastocyst the period between conception and embryonic stages
Embryo; the embryonic period starts at three weeks and continues until the end of the 8th week of pregnancy
Fetus; the fetal stage begins at the end of the 8th week and continues until childbirth
Birth
Child
Neonate (newborn) (0-30 days)
Infant (baby) (1 month-1 year)
Toddler (1-4)
Primary school age (also called prepubescence) (4-12)
Elementary school age (also called middle childhood) (4-8)
Preadolescence (preteen, or late childhood. The child in this and the previous phase are called schoolchild (schoolboy or schoolgirl), when still of primary school age.) (9-12)
Adolescence and puberty (teenage) (13-19)
Young adult (19-25)
Adult (exact minimum age may vary)
Early adulthood (20-39)
Middle age (40-59)
Advanced adult/Senior citizen/Old age (60+)
Death (occurs at various ages, depending on person)
Decomposition (breakdown of the physical body after death)
Also sometimes used are terms that specify one's age in decades, such as:
Twenty something (20-29)
Thirty something (30-39)
Forty something (40-49) (Formerly also Quadragenarian, rarely used since 1980)
Quinquagenarian (50-59)
Sexagenarian (60-69)
Septuagenarian (70-79)
Octogenarian (80-89)
Nonagenarian (90-99)
Centenarian (100-109)
Supercentenarian (110+)
Physical development milestones
Ability to lift and control the orientation of the head
Crawling begins
Walking begins
Speech begins
Voice lowers in pitch (especially noticeable in boys)
Pubic hair appears
Genitals and reproductive organs mature
Menses begin (females)
Body hair and facial hair appears
Note: the Tanner stages can be used to approximately judge a child's age based on physical development.
A fetus (or foetus, or fœtus) is a developing mammal or other viviparous vertebrate, after the embryonic stage and before birth. The plural is fetuses (foetuses, fœtuses) or, very rarely, foeti.
In humans, the fetal stage of development begins at the end of the eighth week after fertilisation, when the major structures and organ systems have formed, until birth.
Etymology and spelling variations
The word "fetus" is from the Latin fetus, meaning "offspring", "bringing forth", or "hatching of young".[1] It has Indo-European roots related to sucking or suckling.[2]
Foetus is an English variation on this, rather than a Latin or Greek word, but has been in use since at least 1594 according to the Oxford English Dictionary, which describes "fetus" as the etymologically preferable spelling. "Fetus" is derived from the Latin verb fere, to conceive, not from the Latin verb foetare, to give birth. The superior etymological spelling is therefore "fetus",[3] and the variant foetus or fœtus may have originated with an error by Saint Isidore of Seville, in AD 620.[4] The preferred spelling in the United States is fetus, but the variant foetus or fœtus persists in other English-speaking countries, and in some medical contexts, as well as in some other languages (e.g. French).
Human fetus
he fetal stage begins eight weeks after fertilization. The fetus is not as sensitive to damage from environmental exposures as the embryo was, though toxic exposures can often cause physiological abnormalities or minor congenital malformation. Fetal growth can be terminated by various factors, including miscarriage, feticide committed by a third party, or induced abortion.
DEVELOPMENT
The following timeline describes some of the specific changes in fetal anatomy and physiology by fertilization age (i.e. the time elapsed since fertilization). However, it should be noted that obstetricians often use "gestational age" which, by convention, is measured from 2 weeks earlier than fertilization. For purposes of this article, age is measured from fertilization, except as noted.
8 weeks (condition at start of fetal stage). The risk of miscarriage decreases sharply at the beginning of the fetal stage.[5] At this point, all major structures, including hands, feet, head, brain, and other organs are present, but they continue to grow, develop, and become more functional.[6] When the fetal stage commences, a fetus is typically about 30 mm (1.2 inches) in length, and the heart is beating.[7] The fetus bends the head, and also makes general movements and startles that involve the whole body.[8] Brain stem activity has been detected as early as 54 days after conception.[9] Some fingerprint formation can be seen from the beginning of the fetal stage.[10]
8 to 15 weeks. The fetus continues to move in distinct motor patterns, picking up new patterns such as localized movement of the arms and legs, hiccups, breathing-like movements, and stretches and yawns .[8] [11] The breathing-like movement of the fetus is necessary for stimulation of lung development, rather than for obtaining oxygen.[12] At nine weeks, the fetus is able to bend fingers around an object; in response to a touch on the foot, the fetus will bend the legs or curl the toes to move away from the object.[13] The face is well-formed and develops a more human appearance. Eyelids close and remain closed for several months. The different appearance of the genitals in males and females becomes pronounced. Tooth buds appear, the limbs are long and thin, and red blood cells are produced in the liver. A fine hair called lanugo develops on the head. The gastrointestinal tract, still forming, starts to collect sloughed skin and lanugo, as well as hepatic products, forming meconium (stool). Fetal skin is almost transparent. More muscle tissue and bones have developed, and the bones become harder. The first measurable signs of EEG activity occur
n the 12th week.[9][14] By the end of this stage, the fetus has reached about 15 cm (6 inches).
16 to 25 weeks. The lanugo covers the entire body. Eyebrows, eyelashes, fingernails, and toenails appear. The fetus has increased muscle development. Alveoli (air sacs) are forming in lungs. The nervous system develops enough to control some body functions. The cochlea are now developed, though the myelin sheaths in the neural portion of the auditory system will continue to develop until 18 months after birth. The respiratory system has developed to the point where gas exchange is possible. The quickening, the first maternally discernable fetal movements, are often felt during this period. A woman pregnant for the first time (i.e. a primiparous woman) typically feels fetal movements at about 18-19 weeks, whereas a woman who has already given birth at least two times (i.e. a multiparous woman) will typically feel movements around 16 weeks.[15] By the end of the fifth month, the fetus is about 20 cm (8 inches).
26 to 38 weeks. The amount of body fat rapidly increases. Lungs are not fully mature. Thalamic brain connections, which mediate sensory input, form. Bones are fully developed, but are still soft and pliable. Iron, calcium, and phosphorus become more abundant. Continuous EEG readings have been observed by the 30th week.[9] Fingernails reach the end of the fingertips. The lanugo begins to disappear, until it is gone except on the upper arms and shoulders. Small breast buds are present on both sexes. Head hair becomes coarse and thicker. Birth is imminent and occurs around the 40th gestational week. The fetus is considered full-term by week 35, which means that the baby is considered sufficiently developed for life outside the womb.[16] It may be 48 to 53 cm (19 to 21 inches) in length, when born.
VARIATION IN GROWTH
There is much variation in the growth of the fetus. When fetal size is less than expected, that condition is known as intrauterine growth restriction (IUGR) also called fetal growth restriction (FGR); factors affecting fetal growth can be maternal, placental, or fetal.[17]
Maternal factors include maternal weight, body mass index, nutritional state, emotional stress, toxin exposure (including tobacco, alcohol, heroin, and other drugs which can also harm the fetus in other ways), and uterine blood flow. A woman's primiparity also may affect fetal weight (firstborns tend to weigh less).
Placental factors include size, microstructure (densities and architecture), umbilical blood flow, transporters and binding proteins, nutrient utilization and nutrient production.
Fetal factors include the fetus genome, nutrient production, and hormone output. Also, female fetuses tend to weigh less than males, at full term.[17]
Fetal growth is often classified as follows: small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA).[18] SGA can result in low birth weight, although premature birth can also result in low birth weight. Low birth weight increases risk for perinatal mortality (death shortly after birth), asphyxia, hypothermia, polycythemia, hypocalcemia, immune dysfunction, neurologic abnormalities, and other long-term health problems. SGA may be associated with growth delay, or it may instead be associated with absolute stunting of growth.
VIABILITY
Five months is currently the lower limit of viability, and viability usually occurs later.[19] According to The Developing Human:
Viability is defined as the ability of fetuses to survive in the extrauterine environment... There is no sharp limit of development, age, or weight at which a fetus automatically becomes viable or beyond which survival is assured, but experience has shown that it is rare for a baby to survive whose weight is less than 500 gm or whose fertilization age is less than 22 weeks. Even fetuses born between 26 and 28 weeks have difficulty surviving, mainly because the respiratory system and the central nervous system are not completely differentiated... If given expert postnatal care, some fetuses weighing less than 500 gm may survive; they are referred to as extremely low birth weight or immature infants.... Prematurity is one of the most common causes of morbidity and prenatal death.[20]
During the past several decades, expert postnatal care has improved with advances in medical science, and therefore the point of viability has moved earlier.[21] As of 2006, the youngest child to survive a premature birth was Amillia Taylor, born at the Baptist Hospital of Miami at 21 weeks and 6 days' gestational age.[22]
FETAL PAIN
The subject of fetal pain and suffering is controversial. The ability of a fetus to feel pain is often part of the abortion debate. However, according to Arthur Caplan, "there is no consensus among the medical and scientific experts about precisely when a fetus becomes pain-capable."[23] Different sources have estimated that the earliest point for pain sensation may be during the first 12 weeks or after 20, 24, or 26 weeks gestation, or months after birth.
THE CIRCULATORY SYSTEM OF FETUS
The circulatory system of a human fetus works differently from that of born humans, mainly because the lungs are not in use: the fetus obtains oxygen and nutrients from the woman through the placenta and the umbilical cord.[24]
Blood from the placenta is carried to the fetus by the umbilical vein. About half of this enters the fetal ductus venosus and is carried to the inferior vena cava, while the other half enters the liver proper from the inferior border of the liver. The branch of the umbilical vein that supplies the right lobe of the liver first joins with the portal vein. The blood then moves to the right atrium of the heart. In the fetus, there is an opening between the right and left atrium (the foramen ovale), and most of the blood flows from the right into the left atrium, thus bypassing pulmonary circulation. The majority of blood flow is into the left ventricle from where it is pumped through the aorta into the body. Some of the blood moves from the aorta through the internal iliac arteries to the umbilical arteries, and re-enters the placenta, where carbon dioxide and other waste products from the fetus are taken up and enter the woman's circulation.[24]
Some of the blood from the right atrium does not enter the left atrium, but enters the right ventricle and is pumped into the pulmonary artery. In the fetus, there is a special connection between the pulmonary artery and the aorta, called the ductus arteriosus, which directs most of this blood away from the lungs (which aren't being used for respiration at this point as the fetus is suspended in amniotic fluid).[24]
POSTNATAL DEVELOPMENT
With the first breath after birth, the system changes suddenly. The pulmonary resistance is dramatically reduced ("pulmo" is from the Latin for "lung"). More blood moves from the right atrium to the right ventricle and into the pulmonary arteries, and less flows through the foramen ovale to the left atrium. The blood from the lungs travels through the pulmonary veins to the left atrium, increasing the pressure there. The decreased right atrial pressure and the increased left atrial pressure pushes the septum primum against the septum secundum, closing the foramen ovale, which now becomes the fossa ovalis. This completes the separation of the circulatory system into two halves, the left and the right.
The ductus arteriosus normally closes off within one or two days of birth, leaving behind the ligamentum arteriosum. The umbilical vein and the ductus venosus closes off within two to five days after birth, leaving behind the ligamentum teres and the ligamentum venosus of the liver respectively.
Differences from the adult circulatory system
Remnants of the fetal circulation can be found in adults:[25][26]
In addition to differences in circulation, the developing fetus also employs a different type of oxygen transport molecule than adults (adults use adult hemoglobin). Fetal hemoglobin enhances the fetus' ability to draw oxygen from the placenta. Its association curve to oxygen is shifted to the left, meaning that it will take up oxygen at a lower concentration than adult hemoglobin will. This enables fetal hemoglobin to absorb oxygen from adult hemoglobin in the placenta, which has a lower pressure of oxygen than at the lungs.
Developmental problems
Congenital anomalies are anomalies that are acquired before birth. Infants with certain congenital anomalies of the heart can survive only as long as the ductus remains open: in such cases the closure of the ductus can be delayed by the administration of prostaglandins to permit sufficient time for the surgical correction of the anomalies. Conversely, in cases of patent ductus arteriosus, where the ductus does not properly close, drugs that inhibit prostaglandin synthesis can be used to encourage its closure, so that surgery can be avoided.
A developing fetus is highly susceptible to anomalies in its growth and metabolism, increasing the risk of birth defects. One area of concern is the mother's lifestyle choices made during pregnancy. Diet is especially important in the early stages of development. Studies show that supplementation of the mother's diet with folic acid reduces the risk of spina bifida and other neural tube defects. Another dietary concern is the consumption of breakfast by the mother. This one factor could lead to extended periods of lower than normal nutrients in the mother's blood, leading to a higher risk of prematurity, or other birth defects in the fetus. During this time alcohol consumption may increase the risk of the development of Fetal alcohol syndrome, a condition leading to mental retardation in some infants.[27] Smoking during pregnancy may also lead to reduced birth weight. Low birth weight is defined as 2500 grams (5.5 lb). Low birth weight is a concern for medical providers due to the tendency of these infants, described as premature by weight, to have a higher risk of secondary medical problems.
Umbilical vein
Circulation
Attached to the uterine lining, the placenta is the site of gas exchange between mother and fetus. The singular umbilical vein carries oxygenated blood from the placenta to the fetus, while two umbilical arteries return deoxygenated blood to the placenta. The three vessels coil around one another within the Wharton's jelly of the umbilical cord and enter the abdomen at the umbilicus.
Inside the fetus, the vein courses alongside the falciform ligament and then to the liver's underside. At the transverse fissure, the vein divides into two vessels, one larger than the other. The larger of the two is joined by the portal vein, and together they enter the right lobe of the liver. The smaller vessel, now called the ductus venosus, diverges away from the liver and joins with the inferior vena cava.
Closure
Within a week of birth, the infant's umbilical vein is completely obliterated and is replaced by a fibrous cord called the round ligament of the liver (also called the ligamentum teres hepatis, from the Latin meaning the same). It extends from the umbilicus to the transverse fissure, where it joins with the ligamentum venosum to separate the left and right lobes of the liver.
Closure of the umbilical vein usually occurs after the umbilical arteries have closed. This prolongs the communication between the placenta and fetal heart, allowing for a sort of autotransfusion of remaining blood from the placenta to the fetus.
Recanalization
Under extreme pressure, the round ligament may reopen to allow the passage of blood. Such recanalization is common in patients with cirrhosis and portal hypertension. Patients with cirrhosis experience rapid growth of scar tissue in and around the liver, often functionally obstructing nearby vessels. Vessel occlusion increases vascular resistance and therefore leads to hypertension. In portal hypertension, the vessels surrounding the liver are subjected to abnormally high blood pressure—so high, in fact, that the force of the blood pressing against the round ligament is sufficient to recanalize the structure.
Catheterization
A newborn baby has a patent umbilical vein for at least a few months. This umbilical vein may be catheterised for ready intravenous access. It may be used as a site for regular transfusion in cases of erythroblastosis or hemolytic disease.
Childbirth
Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy with the emergence of a newborn infant/s from the mother's uterus.
The process of human childbirth is categorized in 3 stages of labour. In the first stage, the uterus begins rhythmic contractions which steadily increase in strength and frequency, gradually widening and thinning the cervix. During the second stage, the infant passes from the uterus, through the cervix and birth canal. In the third stage, the placenta pulls from the uterine wall and is expelled through the birth canal.[1]
The natural birth
Mother and newborn with umbilical cord still attached after a water birth
First stage: contractions
A typical childbirth will begin with the onset of contractions of the uterus. The frequency and duration of these contractions varies with the individual. The onset of labour may be sudden or gradual, and is defined as regular uterine activity in the presence of cervical dilatation.
During a contraction the long muscles of the uterus contract, starting at the top of the uterus and working their way down to the bottom. At the end of the contraction, the muscles relax to a state shorter than at the beginning of the contraction. This draws the cervix up over the baby's head. Each contraction dilates the cervix until it becomes completely dilated, often referred to as 10+ cm (4") in diameter.
A gradual onset with slow cervical change towards 3 cm (just over 1 inch) dilation is referred to as the "latent phase". A woman is said to be in "active labour" when contractions have become regular in frequency (3-4 in 10 minutes) and about 60 seconds in duration. The cervix must shorten (efface) before it can dilate; for first time mothers this can take a substantial period of time and can often be a very tiring and disheartening time. However, it is also a very positive time, as once the cervix is effaced dilatation can occur and the downward journey of the fetus can commence. The now powerful contractions are accompanied by cervical effacement and dilation greater than 3 cm. The labour may begin with a rupture of the amniotic sac, the paired amnion and chorion ("breaking of the water"). The contractions will accelerate in frequency and strengthen. In the "transition phase" from 8 cm–10 cm (3 or 4 inches) of dilation, the contractions often come every two minutes and are typically lasting 70–90 seconds. Transition is often regarded as the most challenging and intense for the mother. It is also the shortest phase.
During this stage, the expectant mother typically goes through several emotional phases. At first, the mother may be excited and nervous. Then, as the contractions become stronger, demanding more energy from the mother, mothers generally become more serious and focused. However, as the cervix finishes its dilation, some mothers experience confusion or bouts of self-doubt or giving up. It is important during this time for the birth partners to stay positive and supportive of the mother; to actively encourage if this is what she wishes and to provide nutrition and hydration in order to keep her energy reserves up.
The duration of labour varies widely, but averages some 13 hours for women giving birth to their first child ("primiparae") and 8 hours for women who have already given birth.
If there is a significant medical risk to continuing the pregnancy, induction may be necessary. As this carries some risk, it is only done if the child or the mother are in danger from prolonged pregnancy. Forty-two weeks' gestation without spontaneous labour is often said to be an indication for induction although evidence does not show improved outcomes when labour is induced for post-term pregnancies. Inducing labour increases the risk of cesarean section uterine rupture in mothers that have had a previous cesarean section.
Second stage: delivery
In the second stage of labour, the baby is expelled from the womb through the vagina by both the uterine contractions and by the additional maternal efforts of "bearing down," which many women describe as similar in sensation to straining to expel a large bowel movement. The imminence of this stage can be evaluated by the Malinas score.
The baby is most commonly born head-first. In some cases the baby is "breech" meaning either the feet or buttocks are descending first. Babies in the breech position can be helped to be born vaginally by a midwife, although caesarean births are becoming more common for breech presentation.
There are several types of breech presentations, but the most common is where the baby's buttocks are born first and the legs are folded onto the baby's body with the knees bent and feet near the buttocks (full or breech). Others include frank breech, much like full breech but the baby's legs are extended toward his ears, and footling or incomplete breech, in which one or both legs are extended and the foot or feet are the presenting part. Another rare presentation is a transverse lie. This is where the baby is sideways in the womb and a hand or elbow has entered the birth canal first. While babies who present transverse will often move to a different position, this is not always the case and a cesarean birth then becomes necessary.
A newborn baby with umbilical cord ready to be clamped
The length of the second stage varies and may be affected by whether a woman has given birth before, the position she is in and mobility. The length of the second stage should be guided by the condition of the fetus and health of the mother. Problems may be encountered at this stage due to reasons such as maternal exhaustion, the front of the baby's head facing forwards instead of backwards (posterior baby), or extremely rarely, because the baby's head does not fit properly into the mother's pelvis (Cephalo-Pelvic Disproportion (CPD)). True CPD is typically seen in women with rickets and bone deforming illnesses or injuries, as well as arbitrary time limits placed on second stage by caregivers or medical facilities.
Immediately after birth, the child undergoes extensive physiological modifications as it acclimatizes to independent breathing. Several cardiovascular structures start regressing soon after birth, such as the ductus arteriosus and the foramen ovale. In some cultures, the father cuts the umbilical cord and the infant is given a lukewarm bath to remove blood and some of the vernix on its skin before being handed back to its parents.
The practice of leaving the umbilical cord to detach naturally is known as a Lotus Birth.
The medical condition of the child is assessed with the Apgar score, based on five parameters: heart rate, respiration, muscle tone, skin color, and response to stimuli. Apgar scores are typically assessed at both 1 and 5 minutes after birth.
Third stage: placenta
Breastfeeding during and after the third stage
In this stage, the uterus expels the placenta (afterbirth). Breastfeeding the baby will help to cause this. The mother normally loses less than 500 mL (2 cups) of blood. It is important to note that the placenta is to never be pulled from the mother by an untrained person; this could cause it to tear and not be expelled in whole. It is essential that the placenta be examined to ensure that it was expelled whole. Remaining parts can cause postpartum bleeding or infection.
The alternative to natural delivery of the placenta is what is called Active Management - this involves administration of a prophylactic oxytocic before delivery of the placenta, and usually early cord clamping and cutting, and controlled cord traction of the umbilical cord.
A Cochrane database study[2] suggests strongly that blood loss and the risk of postpartum bleeding will be reduced in women offered active management of the third stage of labour. However, the group treated with active third phase management, there was an increased risk of unpleasant side effects (eg nausea and vomiting), and hypertension. The authors suggest that this is due to the use of ergometrine as a component of the oxytocic. No advantages or disadvantages were apparent for the baby.
Details of CCT may be found at: http://library.med.utah.edu/nmw/mod2/Tutorial2/menu_norm.html It is important to emphasise that this procedure must not be attempted unless you have been appropriately trained.
After the birth
Medical professionals typically recommend breastfeeding of the first milk, colostrum, to reduce postpartum bleeding/hemorrhage in the mother, and to pass immunities and other benefits to the baby.
Parents usually bestow the infant its given names soon after birth.
Often people visit and bring a gift for the baby.
Many cultures feature initiation rites for newborns, such as naming ceremonies, baptism, and others.
Mothers are often allowed a period where they are relieved of their normal duties to recover from childbirth. The length of this period varies. In China it is 30 days and is referred to as "doing the month" (see Postpartum period). In other countries taking time off from work to care for a newborn is called "maternity leave" and varies from a few days to several months.
Variations
When the amniotic sac has not ruptured during labour or pushing, the infant can be born with the membranes intact. This is referred to as "being born in the caul." The caul is harmless and its membranes are easily broken and wiped away by the doctor or midwife assisting with the childbirth. In medieval times, and in some cultures still today, a caul was seen as a sign of good fortune for the baby, even giving the child psychic gifts such as clairvoyance, and in some cultures was seen as protection against drowning. The caul was often impressed onto paper and stored away as an heirloom for the child. With the advent of modern interventive obstetrics, premature artificial rupture of the membranes has become common, so babies are rarely born in the caul.
Pain
The amounts of pain experienced by women during childbirth varies. For some women, the pain is intense and agonizing; for other women there is little to no pain. Many factors affect pain perception; fear, number of previous births, fetal presentation, cultural ideas of childbirth, birthing position, support given during labor, beta-endorphin levels, and a woman's natural pain threshold. Uterine contractions are always intense during childbirth. Some women report these sensations as painful, though the degree of pain varies from individual to individual. Some women even find the sensations pleasurable.
Non-medical pain control
Some women believe that reliance on analgesic medication is unnatural, or believe that it may harm the child. They still can alleviate labour pain using psychological preparation, education, massage, hypnosis, water therapy in a tub or shower. Some women like to have someone to support them during labour and birth; often female family members such as her mother, a sister, the father of the baby, a close friend, a partner or a trained professional doula. Some women deliver in a squatting or crawling position in order to more effectively push during the second stage and so that gravity can aid the descent of the baby through the birth canal.
The human body also has its own method of pain control for labour and childbirth in the form of beta-endorphins. As a naturally occurring opiate, beta-endorphin has properties similar to pethidine, morphine, and heroin, and has been shown to work on the same receptors of the brain.[3] Like oxytocin, beta-endorphin is secreted from the pituitary gland, and high levels are present during sex, pregnancy, birth, and breastfeeding. This hormone can induce feelings of pleasure and euphoria during childbirth.[4]
Water births are being increasingly chosen by many women as an option for pain relief during labour and childbirth, and waterbirth has been proven in many trials to be not only a safe option for mother and baby, but in many cases show a reduction in the need for further analgesia, and a higher rate of birth 'without injuries'.[5][6][7][8] Many hospitals and birthing centres now offer women the option of waterbirth, either via custom-made 'birthing pools' or large bath tubs, and have policies to safeguard their use.
Meditation and mind medicine techniques for the use of pain control during labor and delivery. These techniques are used in conjunction with progressive muscle relaxation and many other forms of relaxation for the mind and body to aid in pain control for mothers during childbirth. These techniques are a form of natural pain control. One such technique is Calm Birth. This technique is a form of meditation that empowers and liberates the mother by uplifting her body and its natural process to welcoming her new child into the world.[citation needed]
Medical pain control
In Europe, doctors commonly prescribe inhaled nitrous oxide gas for pain control; in the UK, midwives may use this gas without a doctor's prescription. Pethidine (with or without promethazine) may be used early in labour, as well as other opioids, but if given too close to birth there is a risk of respiratory depression in the infant.
Popular medical pain control in hospitals include the regional anesthetics epidural blocks, and spinal anaesthesia. Doctors and many parents favor the epidural block because medication does not enter the mother's circulatory system, thus it does not cross the placenta and enter the bloodstream of the fetus. Some studies find that although epidural use can lengthen the labour and increase the need for operative intervention, it has no adverse effect on perinatal outcome, and is a safe and effective method of pain control.[9][10]
Different measures for pain control have varying degrees of success and side effects to mother and baby. The risks of medical pain control should be balanced against the fact that childbirth can be extremely painful, and anesthetics are an effective and generally safe way to control pain.
Complications and risks of birth
Problems that occur during childbirth are called complications. They can affect the mother or the baby. Sometimes they cause injury or even death. Doctors and midwives are trained to deal with these problems if they should occur.
Infant deaths (neonatal deaths from birth to 28 days, or perinatal deaths if including fetal deaths at 28 weeks gestation and later) are around 1% in modernized countries. The risk of maternal death during childbirth in developed nations is comparatively low; only about 1 in 1800 mothers die in childbirth (only 1 in 3700 in North America). In the Third World, it is a much riskier proposition: neonatal deaths rates in Sub-Saharan Africa and South Asia are more than 3.7%,[11] and on average 1 in 48 women die during childbirth.[12] The "natural" mortality rate of childbirth—where nothing is done to avert maternal death—has been estimated as being between 1,000 and 1,500 deaths per 100,000 births.[13] (See main article: neonatal death, maternal death)
Emergency airlift of woman in labor by the US Coast Guard
The most important factors affecting mortality in childbirth are adequate nutrition and access to quality medical care ("access" is affected both by the cost of available care, and distance from health services). "Medical care" in this context does not refer specifically to treatment in hospitals, but simply routine prenatal care and the presence, at the birth, of an attendant with midwifery skills. A 1983-1989 study by the Texas Department of Health revealed that the infant death rate was 0.57% for doctor-attended births, and 0.19% for births attended by non-nurse midwives. (The comparison may be misleading because higher-risk births are less likely to be attended solely by a midwife.) Conversely, some studies demonstrate a higher perinatal mortality rate with assisted home births.[14] Around 80% of pregnancies are low-risk. Factors that may make a birth high risk include prematurity, high blood pressure, diabetes and a previous cesarean section.
One of the most dangerous risks to the fetus is that of premature birth, and its associated low neonatal weight. The more premature (or underweight) a baby is, the greater the risks for neonatal death and for pulmonary, respiratory, neurological or other sequelae. About 12% of all infants born in the United States are born prematurely. In the past 25 years, medical technology has greatly improved the chances of survival of premature infants in industrialized nations. In the 1950s and 1960s, approximately half of all low birth weight babies in the US died. Today, more than 90% survive. The first hours of life for "premies" are critical, especially the very first hour of life. Rapid access to a Neonatal Intensive Care Unit is of paramount importance.
Some of the possible complications are:
Heavy bleeding during or after childbirth, which is the most common cause of mortality in new mothers, in both developed and undeveloped nations.[11] Heavy blood loss leads to hypovolemic shock, insufficient perfusion of vital organs and death if not rapidly treated by stemming the blood loss (medically with ergometrine and pitocin or surgically) and blood transfusion. Hypopituitarism after obstetric hypovolemic shock is termed Sheehan's syndrome.
Non-progression of labour (longterm contractions without adequate cervical dilation) is generally treated with intravenous synthetic oxytocin preparations. If this is ineffective, Caesarean section may be necessary. Changes in maternal position is effective in many cases.
Fetal distress is the development of signs of distress by the child. These may include rising or decreasing heartbeat (monitored on cardiotocography/CTG), shedding of meconium in the amniotic fluid, and other signs.
Non-progression of expulsion (the head or presenting parts are not delivered despite adequate contractions): this can require interventions such as vacuum extraction, forceps extraction or Caesarean section.
In the past, a large proportion of women died from infection puerperal fever, but since the introduction of basic hygiene during parturition by Ignaz Semmelweis, this number has fallen precipitously.
Lacerations can be painful. An episiotomy was once thought necessary to avoid tears involving the anal sphincter, but its routine use—once normal—has now been shown to increase the risk of deep lacerations especially involving and extending through the anal sphincter.
Instrumental delivery (Forceps and Ventouse)
The mother will have her legs apart supported in stirrups.
If an anaesthetic is not already in place it will be given.
For a forceps delivery an episiotomy will be done (a cut in the perineum or the region between the vagina and anus), for ventouse extraction an episiotomy is not always done.
After the head is delivered the rest of the delivery is done in the manual method.
After episiotomy or tears the mother is stitched up.
In some cases a 'Trial of Forceps' will be tried out, this will be done in the operating theatre, meaning they will try a forceps delivery and will switch to a caesarean section if it fails.
