Obstetrics by Ten Teachers, 19th Edition Philip Baker. The nineteenth edition has been thoroughly updated, integrating clinical material صيغة الكتاب: pdf. Obstetrics by Ten Teachers, 19E - Ebook download as PDF File .pdf), Text File . txt) or Obstetrics by Ten Teachers Kenny, Louise, Baker, Philip N 19th edition. Together with its companion Obstetrics by Ten Teachers, the volume has been edited carefully to ensure 19th edition consistency of structure, style and level of.
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Obstetrics by ten teachers 19th [email protected] 1. OBSTETRICS byTenTeachers blamtertulabco.cf; 2. OBSTETRICS. The first edition was published as Midwifery by Ten Teachers in , and was Thus, whilst the 19th edition is written for the medical student, we hope the text. NIHR Clinician Scientist and Honorary Consultant in Obstetrics. Maternal & Fetal . with those of its sister text Gynaecology by Ten Teachers. The books can.
In addition, accurate dating reduces the need for post-dates induction of labour. In late pregnancy, many women will have long forgotten their LMP date, but will know exactly when their EDD is, and it is therefore more straightforward to ask this.
Taking the history Social history Some aspects of history taking require considerable sensitivity, and the social history is one such area. There are important facts to establish, but in many cases these can come out at various different parts of the history and some can almost be part of normal conversation.
It is important to have a list of things to establish in your mind. It is here more than anywhere that some local knowledge is helpful, as much can be gained from knowing where the patient lives.
However, be careful not to jump to conclusions, as these can often be wrong. Husbands clearly have a strong voice in decision making. It is recommended that all women are seen on their own at least once during pregnancy, so that they can discuss this, if needed, away from an abusive partner. This is not always easy to accomplish. If you happen to be the person with whom this information is shared, you must ensure that it is passed on to the relevant team, as this may be the only opportunity the woman has to disclose it.
Be aware of this. Smoking, alcohol and illicit drug intake also form part of the social history. Smoking causes a reduction in birthweight in a dose-dependent way.
It also increases the risk of miscarriage, stillbirth and neonatal death. There are interventions that can be offered to women who are still smoking in pregnancy see Chapter 8, Antenatal obstetric complications. Complete abstinence from alcohol is advised, as the safety of alcohol is not proven.
However, alcohol is probably not harmful in small amounts less than one drink per day. Binge drinking is particularly harmful and can lead to a constellation of features in the baby known as fetal alcohol syndrome see Chapter 8, Antenatal obstetric complications.
Approximately 0. Be careful not to make assumptions. During the booking visit, the midwife should directly enquire about drug taking.
If it is seen as part of the long list of routine questions asked at this visit, it is perceived as less threatening. However, sometimes this information comes to light at other times. Cocaine and crack cocaine are the most harmful of the illicit drugs taken, but all have some effects on the pregnancy, and all have financial implications see Chapter 8, Antenatal obstetric complications. Previous obstetric history Past obstetric history is one of the most important areas for establishing risk in the current pregnancy.
It is helpful to list the pregnancies in date order and to discover what the outcome was in each pregnancy.
When you have noted all the pregnancies, you can convert this into the obstetric shorthand of parity. This is often confusing. In terms of parity, therefore, twins count as two. Thus a woman at 12 weeks in this pregnancy who has never had a pregnancy before is gravida 1, parity 0.
If she delivers twins and comes back next time at 12 weeks, she will be gravida 2, parity 2 twins. A woman who has had six miscarriages and is pregnant again with only one live baby born at 25 weeks will be gravida 8, parity 1.
The other shorthand you may see is where parity is denoted with the number of pregnancies that did not result in live birth or stillbirth after 24 weeks as a superscript number.
However, when presenting a history, it is much easier to describe exactly what has happened, e. She has had six miscarriages at gestations of 8—12 weeks and one spontaneous delivery of a live baby boy at 25 weeks. Past gynaecological history The regularity of periods used to be important in dating pregnancy see Dating the pregnancy p.
Women with very long cycles may have a condition known as polycystic ovarian syndrome. This is a complex endocrine condition and its relevance here is that some women with this condition have increased insulin resistance and a higher risk for the development of gestational diabetes. Also, some women will conceive with an intrauterine device still in situ.
This carries an increase in the risk of miscarriage. This is only of relevance in early pregnancy. However, it is important to establish that any infections have been adequately treated and that the partner was also treated. The date of the last cervical smear should be noted. Every year a small number of women are diagnosed as having cervical cancer in pregnancy, and it is recognized that late diagnosis is more common around the time of pregnancy because smears are deferred.
It is also important that smears are not deferred in women who are at increased risk of cervical disease e.
Remember that if it is deferred at this point, it may be nearly a year before the opportunity arises again. If there has been irregular bleeding, the cervix should at least be examined to ensure that there are no obvious lesions present.
If a woman has undergone treatment for cervical changes, this should be noted. Knife cone biopsy is associated with an increased risk for both cervical incompetence weakness and stenosis leading to preterm delivery and dystocia in labour, respectively. There is probably a very small increase in the risk of preterm birth associated with large loop excision of the transformation zone LLETZ ; however, women who have needed more than one excision are likely to have a much shorter cervix, which does increase the risk for second and early third trimester delivery.
Previous ectopic pregnancy increases the risk of recurrence to 1 in It is also important to know the site of the ectopic and how it was managed. The implications of a straightforward salpingectomy for an ampullary ectopic are much less than those after a complex operation for a cornual ectopic.
Women who have had an ectopic pregnancy should be offered an early ultrasound scan to establish the site of any future pregnancies. In severe pre-eclampsia and some intracranial conditions space-occupying lesions, benign intracranial hypertension , papilloedema may be present. Oedema of the extremities affects 80 per cent of term pregnancies. Its presence should be noted, but it is not a good indicator for pre-eclampsia as it is so common.
This can be very painful if there is excessive oedema, and when there is it is so obvious that testing for pitting is not necessary. More importantly, facial oedema should be commented upon. These are most easily checked at the ankle.
The presence of more than three beats of clonus is pathological see Chapter 10, Pre-eclampsia and other disorders of placentation. Presentation skills Part of the art of taking a history and performing an examination is to be able to pass this information on to others in a clear and concise format. It is not necessary to give a full list of negative findings; it is enough to summarize negatives such as: Adapt your style of presentation to meet the situation.
A very concise presentation is needed for a busy ward round. In an examination, a full and thorough presentation may be required. Be very aware of giving sensitive information in a ward setting where other patients may be within hearing distance. Was it normal? Have there ever been any that were abnormal? If yes, what treatment has been undertaken?
History of maternity care in the UK Many of the changes have been driven by political and consumer pressure. Only recently has any good quality research been conducted into which aspects of care actually make a difference to women and their babies.
In the United Kingdom, we are in the enviable position of being able to receive quality maternity care, free at the point of need. This is not so for the majority of women across the world. Despite signing up to ambitious targets for the reduction of maternal mortality, the global community is failing to achieve reductions in mortality, making pregnancy and childbirth a life-threatening challenge for millions of women.
Up until this point, successive governments had paid little attention to maternal or child health. The introduction of the NHS provided for maternity services to be available to all without cost.
As part of these arrangements, a specified fee was paid to the general practitioner GP depending on whether he or she was on the obstetric list. This encouraged a large number of GPs to take an interest in maternity care, reversing the previous trend to leave this work to the midwives.
This failed to take into account prematurity and poor education as reasons for decreased visits and increased mortality. However, antenatal care became established, and with increased professional contact came the drive to continue to improve outcomes with an emphasis on mortality maternal and perinatal , without always establishing the need for or safety of all procedures or interventions for all women.
The ability to see into the pregnant uterus in with ultrasound brought with it a revolution in antenatal care. This new intervention became quickly established and is now so much part of current antenatal care that the fact that its use in improving the outcome for low-risk women was never proven has been little questioned.
Women themselves were pushing to at least be allowed the choice to deliver in hospital. It made a number of recommendations. Among these were: An increasing number of patients should be delivered in large units; selection of patients should be improved for smaller consultant units and isolated GP units; home deliveries should be phased out further. This report and the subsequent reports Maternity Care in Action, Antenatal and Intrapartum Care, and Postnatal and Neonatal Care led to a policy of increasing centralization of units for delivery and consequently care.
Thus home deliveries are now very infrequent events, with most regions reporting less than 2 per cent of births in the community, the majority of these being unplanned. The gradual decline in maternal and perinatal mortality was thought to be due in greater part to this move, although proof for this was lacking.
Indeed, the decline in perinatal mortality was least in those years when hospitalization increased the most. As other new technologies became available, such as continuous fetal monitoring and the ability to induce labour, a change in practice began to establish these as the norm for most women.
In England and Wales between and , the induction rate rose from During the s, with increasing consumer awareness, the unquestioning acceptance of unproven technologies was challenged.
Women, led by the more vociferous groups such as the National Childbirth Trust NCT , began to question not only the need for any intervention but also the need to come to the hospital at all.
The professional bodies also began to question the effectiveness of antenatal care. The government set up an expert committee to review policy on maternity care and to make recommendations. This committee produced the document Changing Childbirth Department of Health, Report of the Expert Maternity Group, , which essentially provided downloadrs and providers with a number of action points aiming to improve choice, information and continuity for all women.
Nevertheless, this landmark report did provide a new impetustoexaminetheprovisionofmaternitycareinthe UK and enshrine choice as a concept in maternity care.
The most recent government document on maternity care, Maternity Matters, aims to address inequalities in maternity care provision and uptake and is essentially a document for commissioners to assess maternity care in their area and to ensure that safe and effective care is available to all women. The pendulum has swung back, with the government now moving towards increased choices for women including birth at home or in a stand- alone midwifery unit.
Coordination of research: This has led to the evaluation of each aspect of antenatal, intrapartum and post-natal care, and allowed each to be meticulously examined on the The National Screening Committee is responsible for developing standards and strategies for the implementation of these.
The provision of national standards means that new tests are critically evaluated before being offered to populations. Conditions for which screening is currently not recommended, such as group B streptococcus carriage, are regularly reviewed against current evidence.
Antenatal screening is now offered for: Newborn screening includes: These include developing guidelines, setting standards for the provision of care, training and revalidation, audit and research. They are reviewed three- yearly and are accessible to all on the college website www. Concentrating particularly on the randomized controlled trial design, and using meta-analysis, obstetric practice has been scrutinized to an extent unique in medicine.
Now the collaboration covers all branches of medicine. It is serially updated to keep up with published work and represents an enormous body of information available to the clinician. Involvement of professional bodies and consumer groups in maternity care Maternity care is considered so important that many clinical, political and consumer bodies are now involved in how it is provided.
National Institute for Health and Clinical Excellence As can be seen from the above, maternity care has been the subject of political debate for the last years. More recently, attention has been paid to differences in standards of health care across the UK. The National Institute for Health and Clinical Excellence NICE has evaluated maternity care in great detail and has published a number of important guidelines, covering antenatal, intrapartum and post-natal care.
Trusts are judged by their ability to provide care to the standards set out in these guidelines. The process of guideline development is rigorous and stakeholders are consulted at each stage of development. The guidelines are available through the NICE website www. National Screening Committee Screening has formed a part of antenatal care since its inception.
Antenatal care is essentially screening in It has provided interesting data for the trends in Caesarean section across the UK.
CMACE produce national and local audits and reports into a wide range of maternal and child health issues. From an obstetric perspective, the most important is the triennial report on maternal mortality. These standards provide important drivers to organizations such as the Clinical Negligence Scheme for Trusts in setting standards for levels of care and performance by hospitals.
Revalidation and continuing professional development Revalidation of professionals is increasingly important. In order to be maintained on the General Medical Council Register, all doctors will need to produce evidence that they are keeping up to date within their chosen specialty.
Part of the revalidation process involves the coordination and documentation of education and professional developmental activity. The RCOG plays the major role in this important task. Training The college also has an important role in ensuring quality of training of doctors wishing to become consultants.
It is recognized that with the limitations on working time that have come into force as a result of the European Working Time Directive, and a government initiative to limit total time in training, junior doctors now work many fewer hours than previously.
Training has changed from an apprenticeship to a much more structured programme. Additionally there is a longer, two to three years, training scheme in maternal and fetal medicine, aimed at those who wish to train to become sub-specialists in this area. The audit came about as a result of concern regarding the increasing Caesarean 0 1 2 3 4 5 6 7 8 Ratepermaternities Triennium Venous thromboembolism after CS Figure 2.
As individual hospitals cannot hope to meet the cost of huge settlements, sometimes running into millions of pounds, an insurance scheme has been established. The amount any individual hospital has to pay to the scheme is graded from level 0 to 3. The insurance premium is discounted by 10 per cent for a level 1 However, many groups are making efforts to canvass the opinions of those rarely heard, such as teenagers and women who speak little or no English.
Choice is now being sought by consumers in a way never experienced before. Maternity care: In the worst areas sub-Saharan Africa there were deaths per live births, giving women in these areas a one in 26 risk of not surviving childbirth.
At the Millennium Summit in , the international community set improving maternal health as one of the eight Millennium Development Goals. The aim was to reduce the maternal mortality ratio MMR by three-quarters by To achieve this, a 5. The survey has shown that maternal mortality has fallen at less than 1 per cent per year. In , it was decided to assess obstetrics separately, as many trusts were failing on the obstetric standards only. The standards set by CNST are stringent.
They cover: Within each standard is a wide range of organizational and clinical standards. Trusts are assessed at least every two years. Improvements in maternity care are therefore linked to financial incentive, and measurable improvements in many units have been brought about as managers realize the importance of improving standards of care. Consumer groups There are now more consumer and support groups in existence than ever before. As well as providing support and advice for women, often at times of great need, they also allow women to have a louder voice in the planning and provision of maternity care.
When these committees work well, they can provide essential consumer input into service delivery at a local level. Consumers should make up at least one-third of the membership of the MSLCs. Interestingly, it was this drive that led to the demise of many local units, the centralization of obstetric services and a huge reduction in the numbers of home deliveries, something that consumer groups are now trying to reverse.
Many groups have been criticized as being unrepresentative of the whole population. This will continue to be so, as disenfranchised groups are less Sisterhood methods have been employed, whereby cohorts of women are questioned about the survival of their adult sisters. This method has an advantage of reducing the sample size. It is less useful in areas of lower fertility where women have fewer than four pregnancies and where there is substantial migration of populations. Other types of data collection include reproductive age mortality surveys and census data.
Surveys tend to be more accurate, but are very time-consuming and expensive. Census data tend to be of lesser quality, but can capture data from larger populations. It is recognized, therefore, that data collected for analysis of worldwide maternal mortality are estimates based on the best available sources. Figure 2. Measuring maternal deaths In the UK, we tend to take for granted our ability to collect accurate data.
However, for the international community this is a major issue. In addition to the MMR and the MMRate, it is possible to calculate the adult lifetime risk of maternal mortality for women in the population Table 2. Table 2. Number of maternal deaths during a given time period per livebirths during the same time period Maternal mortality rate: Number of maternal deaths in a given period per women of reproductive age during the same time period Adult lifetime risk of maternal death: However, the practicalities of data collection mean that many civil data sets are incomplete.
Where civil data collection is not available, household surveys are often used. Three-quarters of maternal deaths are due to a complication directly attributable to the pregnancy, such as haemorrhage or hypertension. The remaining quarter of deaths are due to conditions that may be worsened by the pregnancy, such as heart disease.
First class delivery: HSMO, CNST standards for maternity services: Cochrane Library: Department of Health. Changing childbirth. Report of the Expert Maternity Group. HMSO, Maternity Matters: DOH, Most of the common complications of childbirth do not cause death within a short time. If facilities for transfer of women are available, there can be a dramatic effect on maternal mortality. The most life- threatening complication at delivery is haemorrhage.
In the WHO advocated the presence of a skilled attendant at every delivery. Reaching the Millennium Goal will not be achieved at the present slow rate of change. Political pressure on governments to improve health care for women will continue to need to be high on the worldwide agenda. Other direct causes include ectopic pregnancy, embolism, anaesthesia- related causes.
Indirect causes include anaemia, malaria, heart disease. Maternal systems adapt as pregnancy progresses to accommodate the increasing demands of fetal growth and development.
Management of both healthy and diseased pregnancy necessitates knowledge of the physiology of normal pregnancy.
Understanding these adaptations enable clinicians to identify abnormal changes that lead to complications, as well as recognize changes that mimic disease, and understand altered responses to stress. This chapter outlines maternal physiological adaptations to pregnancy, indicating the potential for misinterpretation of clinical signs and providing explanations for the changes that occur.
Most pregnant women report symptoms of pregnancy by the end of the sixth week after the last menstrual period. Following implantation, the maternal adaptation to pregnancy can be categorized based on the following functions: Increased availability of metabolic substrates and hormones is achieved by increases in dietary intake, as well as endocrine changes that increase the availability of substrates like glucose.
Transport capacity is enhanced by increases in cardiac output, facilitating both the transport of substrates to the placenta, and fetal waste products to maternal organs for disposal.
The placenta regulates maternal—fetal exchange by 10—12 weeks gestation, but transfer occurs through other mechanisms before this. Volume homeostasis Maternal blood volume expands during pregnancy to allow adequate perfusion of vital organs, including the placenta and fetus, and to anticipate blood loss associated with delivery. The rapid expansion of blood volume begins at 6—8 weeks gestation and plateaus at 32—34 weeks gestation.
This expanded extracellular fluid volume accounts for between 8 and 10kg of the average maternal weight gain during pregnancy. Reductions in pCO2 activate compensatory buffering mechanisms so that potentially hazardous alkalosis is prevented. An increase in the concentration of carbonic anhydrase within maternal erythrocytes has been reported. Palpitations are common and usually represent sinus tachycardia. Arterial blood gas values differ in pregnant compared to non-pregnant women. The increased oxygen consumption coupled with the decreased FRC decreases maternal oxygen reserve and predisposes the pregnant woman to hypoxaemia and hypocapnia during periods of respiratory depression or apnoea.
Around one-third of the increase is necessary for the metabolic demands of placenta and fetus. In consequence. Arterial gases Progesterone has respiratory stimulant properties and the greatly increased levels in pregnancy are thought to be responsible for increasing alveolar ventilation through increasing tidal volume.
Premature atrial and ventricular ectopic beats are common in pregnancy and the peripheral pulse is increased in volume. Binding of 2. The latter can also cause decreased venous return to the heart. They may also occur as increased awareness of the heart beating either regularly or in association with extrasystoles. This increases the availability of oxygen within the tissues. The reduction in pCO2 has implications for acid—base balance. The mechanisms responsible are uncertain.
A mean diastolic blood pressure of Increases in both heart rate and stroke volume contribute. Stroke volume.
After Chamberlain and Broughton Pipkin. As blood pressure does not rise in pregnancy. At delivery. Clinical physiology in obstetrics. A progressive increase in heart rate continues until the third trimester of pregnancy.
The cardiac output is elevated at the onset of labour to over 7. Cardiovascular system venous pressure is also unchanged. In normal pregnancy. An 11 per cent fall in mean arterial blood pressure at rest has been shown by 15 weeks gestation.
Changes in the left ventricular size and volume mean the apex beat is more forceful. This increase is due to the uterine contractions each of which squeezes — mL of blood into the maternal circulation.
The increase in cardiac output is caused partly by an increase in heart rate. A 70 per cent reduction in peripheral resistance has been demonstrated by 8 weeks gestation. Accurate determination of diastolic pressure is therefore very important. The first heart sound is loud and sometimes split.
The third heart sound is frequently misinterpreted as a diastolic murmur. During pregnancy. Delayed gastric motility and prolonged gastrointestinal transit time may also lead to constipation and alter the bioavailability of medications. Salivary oestrogen levels are increased.
Gut As gestation advances. Mechanical factors. An ejection systolic murmur can be heard in 96 per cent of apparently normal pregnant women. The main salivary changes in pregnancy include variations in pH and composition. Gastric motility decreases further during labour and emptying remains delayed during the puerperium.
Elevated circulating oestrogen and progesterone levels are implicated in increasing vascular permeability and decreasing immune resistance. Ausculatory changes in pregnancy are well documented. While teeth usually retain their structure. Gastrointestinal changes Oral The physiological changes of pregnancy include effects on mucous membranes.
As a result of all of these changes. Increased tooth mobility.
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Elevated progesterone levels reduce lower oesophageal sphincter tone and increase the placental production of gastrin. Liver The liver. The hormone levels of pregnancy also affect the response of the periodontal tissues to bacterial colonization. The calyces. Despite chronic vasodilatation. Portal vein pressure is increased in late pregnancy. The kidneys and urinary tract function remains normal. This physical change. Renal parenchymal volumes also increase during pregnancy.
Levels fall after delivery.
Obstetrics by Ten Teachers, 19E
By the third trimester. GFR then falls by about 20 per cent in the third trimester. Although hepatic protein production increases. By 6 weeks postpartum. The kidneys and urinary tract Anatomic changes The kidneys increase in size in normal pregnancy.
Oestrogen mediates the adaptation of the uterine smooth muscle to pregnancy. As GFR increases without alterations in the production of creatinine and urea. Potassium metabolism remains unchanged.
Glucose reabsorption occurs secondarily to the absorption of sodium and therefore other factors contributing to volume homeostasis and sodium retention may also be involved in the physiological glycosuria of pregnancy.
The increase in GFR may be partially responsible.
The average plasma urea level of 3. The lower segment is the part of the uterus and upper cervix which lies between the attachment of the peritoneum of the uterovesical pouch superiorly and the level of the internal cervical os inferiorly. Plasma urate concentrations decrease by over 25 per cent from 8 weeks gestation. High levels of maternal oestradiol and progesterone induce both hyperplasia and hypertrophy of the myometrium.
The growing size of the uterine contents is an important stimulus. Sodium balance is maintained. It is thinner. Early morning urine is more alkaline than in non-pregnant women. Creatinine clearance increases by 25 per cent at 4 weeks gestation and by 45 per cent at 9 weeks.
There is also increased renal excretion of various nutrients. Prostaglandins induce a remodelling of cervical collagen in late gestation. Deposition of fat around glandular tissue occurs. These are apparent initially as Braxton Hicks. Steroid hormones also have an effect on signalling pathways.
As these junctions mature. Lactation is initiated by early suckling. With increasing gestation. The retraction of the thick intermediate layer IL of muscle with increasing gestation thins the lower segment As well as changes in the size and number of myometrial cells. This has the effect of drawing the anatomical internal cervical os A further from the histological internal cervical os H. These intercellular gap junctions allow changes in membrane potential to spread rapidly from one cell to another.
Prolactin is essential for the stimulation of milk secretion and during pregnancy prepares the alveoli for milk production. This discharge has a more acid pH than non-pregnant vaginal secretions 4. Reproductive organs pregnancy.
Towards the end of pregnancy. Although prolactin concentration increases throughout pregnancy. This becomes visible on the ectocervix and is called an ectropion. Released during labour as well.
Pituitary gland The pituitary gland enlarges during normal pregnancy and concentrations of prolactin reach levels during pregnancy that are fold higher than in the non-pregnant state. Oestrogen has a stimulatory role in this process and hPL is inhibitory. Many physiological adaptations to pregnancy are organized by the maternal brain.
Afferent signals to posterior pituitary increasing oxytocin release. Oxytocin causes contraction of the myoepithelial cells surrounding the glandular ducts.
Therefore prolactin production by the. This results in the release of prolactin and oxytocin. Oxytocin released from the posterior pituitary causes contraction in myoepithelial cells surrounding the alveoli and small ducts.
Afferent signals to anterior pituitary increasing prolactin release. Endocrinology Complex endocrinological changes occur in pregnancy. The endocrinological mechanisms that regulate prolactin production in the non-pregnant state. Prolactin induces milk production by the glandular tissue of the breast. Suckling induces afferent signals to the anterior and posterior pituitary.
Other hormones exert their actions indirectly. Free T4 fT4. The increased GFR of pregnancy results in an increased renal loss of iodide. They also have effects on many other tissues during pregnancy. Sex steroid hormones are produced in large quantities by the placenta and fetus. Uterus and placenta Many pregnancy-specific peptides are produced within the uterus. During normal pregnancy. Increased prolactin production is essential for lactation as already discussed but also acts in the brain to reduce responses to stress.
This leads to increased production of total T3 tri-iodothyronine and T4 thyroxine. Both oestrogen and progesterone have effects on the myometrium. In contrast to prolactin. Human chorionic gonadotrophin has a major role during early pregnancy in maintaining the function of the corpus luteum.
Concentrations of oestrogens and progesterone increase substantially from early pregnancy. However the physiological changes of pregnancy. The best known is hCG. A progressive increase in maternal circulating concentrations of cortisol throughout normal pregnancy has been noticed from as early as Endocrinology anterior pituitary gland continues despite intrauterine production from cells within the decidua.
It is likely that hPL is also involved in suppressing hGH release. This is followed by a fall in fT4 concentration with advancing gestation.
As a result of the increased tissue mass the energy cost of maintenance. Circulating concentrations of the antinatriuretic hormones aldosterone and deoxycorticosterone increase ten-fold in pregnancy. Maternal plasma ACTH levels are ten-fold higher in labour than when not pregnant. The energy cost of pregnancy includes energy deposited in maternal and fetal tissues. The increased production of angiotensins. Plasma CRH. Another function is to stimulate the fetal adrenal gland both directly and through stimulation of the fetal pituitary to synthesize and release cortisol.
Thus the progression of gestation is linked to the timing of fetal development. The placental regulation of its own metabolism through effects on the fetus. Plasma aldosterone levels rise seven to eight-fold during the first trimester. Cortisol responses to stressors are reduced in pregnant women. Rates of weight gain vary across the trimesters of pregnancy.
Weight gain during pregnancy consists of the products of conception fetus. The lack of diurnal variation of cortisol and the attenuated response to dexamethasone suppression suggest that placental ACTH may have a role in regulating maternal cortisol levels.
Progesterone has natriuretic properties. Cortisol reaches two-to three-fold higher concentrations than in the non-pregnant. The appropriate gestational weight gain for optimal pregnancy outcome is the subject of much debate.
Corticotrophin-releasing hormone CRH is produced by the placenta in the second half of pregnancy. Fetal cortisol drives the placental-fetal adrenal axis through positive feedback that results in increasing oestrogen production over gestation.
ACTH and cortisol concentrations increase several-fold with the onset of labour and delivery. In healthy well-nourished women. Much of the cortisol is bound to cortisolbinding globulin CBG. The increase in gut calcium absorption is a result of increased production of a metabolite of vitamin D3. Whether this results from increased transplacental transfer of glucose or from the growthpromoting characteristics of insulin is unclear. Omega-3 fatty acids Omega-3 fatty acids are essential and can only be obtained from the diet.
There are three potential methods of maternal adaptation: No consistent changes have been reported in circulating concentrations of other agents involved in calcium metabolism.
Metabolism with normal pre-pregnancy BMI 20— Since plasma albumin concentrations decrease during pregnancy. Both the higher concentration of oestrogen and insulin resistance are thought to be responsible for the hypertriglyceridaemia of pregnancy. HDL-cholesterol increases by 12 weeks in response to oestrogen and remains elevated throughout pregnancy. Observational studies have shown either no change or a small decline in maternal storage forms of vitamin D during pregnancy.
An oral glucose tolerance test at this time shows an enhanced response compared to the non-pregnant state. Pregnancy is also associated with alterations in insulin receptor binding. Insulin action in late normal pregnancy is 50—70 per cent lower than in non-pregnant women and insulin resistance is thought to allow shunting of nutrients to the fetus. This pattern changes during the second half of pregnancy.
Carbohydrate metabolism Calcium metabolism Changes in carbohydrate and lipid metabolism occur during pregnancy to ensure a continuous supply of nutrients to the growing fetus. Lipid metabolism Changes in hepatic and adipose metabolism alter circulating concentrations of triacylglycerols. Production of 1. Women with high BMI not only deliver infants with higher birthweights.
During lactation. Requirements in pregnancy have not been established but are presumed to be There is little change in the circulating concentration of unbound ionized calcium.
This change may involve hPL or other growth-related hormones. Several factors affect their development. Montgomery tubercles are small sebaceous glands on the areolae of the breasts that enlarge and hypertrophy during early pregnancy. The underlying cause is uncertain. Linear violaceous bands develop on the abdomen and sometimes on the thighs.
Pigmentation usually regresses after delivery but may persist in less than 10 per cent of those affected. Sebaceous gland activity is increased during the second half of pregnancy with greasy skin.
Docosahexaenoic acid DHA. At present. Growth and increase in the number of naevi have also been reported. Striae persist postpartum but become less evident. There is a recognized association between maternal fatty acid intake in pregnancy and fetal visual and cognitive development. Skin Hyperpigmentation can be localized or generalized and affects almost 90 per cent of pregnant women. This hyperpigmentation results from the deposition of melanin in the epidermis.
Acne may also commence during pregnancy. Pruritus of the abdomen may be an accompanying feature. The linea alba darkens to a brown line along the midline of the abdomen. Women often notice thickening of scalp hair during pregnancy and a prolonged anagen phase has been demonstrated. Striae gravidarum stretch marks occur in most pregnant women.
This shedding may persist for several months postpartum and is most likely precipitated by the sudden hormonal changes at delivery as well as the stress of labour. It is known that these fatty acids are essential for the developing fetus. All of these changes appear to regress after delivery. Pre-existing moles. Seminars in Anesthesia Anesthetic implications of maternal physiological changes during pregnancy.
Applied Physiology. Most are advantageous and allow the mother to cope with the increased physical and metabolic demands of the pregnancy. Wolfe LA. Additional reading Butte NF. Hill CC. Current Problems in Cardiology.
Broughton-Pipkin F. Weissgerber TL. Gorman SR. Chamberlain G. Physiological and biological skin changes in pregnancy. Muallem MM. Sklansky MS. Hansson LO. BJOG Energy requirements during pregnancy and lactation. Rubeiz NG. Reference values for clinical chemistry tests during normal pregnancy. Wallace JM. Public Health Nutrition. Pickinpaugh J. Axelsson O. Physiological adaptation in early human pregnancy: Blackwell Science. King JC. Surgical Clinics of North America Palm M.
Gynaecology by Ten Teachers 20th Edition
Rosen MA. Larsson A. Clinics in Dermatology. Hameed AB. Additional reading Summary Many physiological changes occur with normal pregnancy and these changes impact every organ system. Physiologic changes in pregnancy. Holmes VA. Some have important clinical implications: Haemostasis in normal pregnancy: Biochemical Society Transactions. Fetal growth is dependent on adequate transfer of nutrients and oxygen across the placenta It is important to note.. Fetal hyperinsulinaemia Factors affecting these are discussed below and in Chapter This in itself is dependent on appropriate maternal nutrition and placental perfusion.
In particular. One of the challenges in obstetric practice is to identify potentially growth-restricted fetuses and then. Determinants of fetal birthweight? Determinants of birth weight are multifactorial In the medium term In addition The ultimate birthweight is therefore the result of the interaction between the fetal genome and the maternal uterine environment Other factors are important in determining fetal growth and include.
Other complications to which these growth-restricted babies are more prone include neonatal hypothermia Insulin and thyroxine T4 are required through late gestation to ensure appropriate growth in normal and adverse nutritional circumstances They affect the metabolic rate This chapter provides an overview of the development For example Pre-eclampsia and other disorders of placentation Fetal growth The failure of a fetus to reach its full growth potential.
Other factors relate to fetal. The umbilical circulation carries fetal blood to the placenta for gas and nutrient exchange. Chronic maternal disease may restrict fetal growth. Teenage pregnancy is also associated with FGR. Such diseases are largely those that affect placental function or result in maternal hypoxia. Fetal development control is suboptimal. These conditions are discussed further in Chapter Placental infarction secondary to maternal conditions such as those mentioned above or premature separation as in placental abruption can impair this transfer and hence fetal growth.
Hypertension can lead to placental infarction which impairs its function. The fetal circulation is characterized by four shunts which ensure that the best. The use of drugs is often associated with smoking and alcohol use but there is evidence to suggest that heroin is independently associated with a reduction in birthweight.
This effect may be through toxins. Oxygenated blood is returned to the fetus via Fetal development Cardiovascular system and the fetal circulation The fetal circulation is quite different from that of the adult Figure 4.
South Asian and Afro-Caribbean. The umbilical arteries arise from the caudal end of the dorsal aorta and carry deoxygenated blood from the fetus to the placenta. Heavier and taller mothers tend to have bigger babies and certain ethnic groups lighter babies e. Babies born to mothers who smoke during pregnancy deliver babies up to g lighter than non-smoking mothers. Maternal thrombophilia can also result in placental thrombosis and infarction. These shunts are the: Infection Although relatively uncommon in the UK.
A small proportion of blood oxygenates the liver but the bulk passes through the ductus venosus to bypass the liver and joins the inferior vena cava IVC as it enters the right atrium.
Ventilation of the lungs opens the pulmonary circulation. The ductus is a narrow vessel and high blood velocities are generated within it. Prior to birth. The ductus arteriosus closes functionally within a few days of birth. Premature closure of the ductus has been reported with the administration of cyclooxygenase inhibitors. Deoxygenated blood returning from the head and lower body flows through the right atrium and ventricle and into the pulmonary artery after which it bypasses the lungs to enter the descending aorta via the ductus arteriosus which connects the two vessels.
Only a small portion of blood from the right ventricle passes to the lungs. At birth. Harrington and S. By this means. About 50 per cent goes to the head and upper extremities. This streaming of the ductus venosus blood. The ductus venosus stream passes across the right atrium through a physiological defect in the atrial septum called the foramen ovale to the left atrium. This delay in closure of the ductus arteriosus is most commonly seen in premature infants.
The baby remains cyanosed and can suffer from life-threatening hypoxia. Fetal development adequate breathing. The primitive gut consists of three parts.
Acute complications include hypoxia and asphyxia. The hindgut endoderm develops into the descending colon. In infants delivering preterm. A consequent increased pressure in the left atrium leads to closure of the foramen ovale. While herniated. Respiratory system The lung first appears as an outgrowth from the primitive foregut at about 3—4 weeks postconception and by 4—7 weeks epithelial tube branches and vascular connections are forming.
The foregut endoderm gives rise to the oesophagus. This delay. It occurs in more than 80 per cent of infants born between 23 and 27 weeks. It is a mix of phospholipid and protein. The production of lecithin is enhanced by cortisol. The midgut endoderm gives rise to the distal half of the duodenum. The incidence and severity of RDS can be reduced by administering steroids antenatally to mothers at risk of preterm delivery.
Dilatation of the gas exchanging airspaces. Surfactant prevents the collapse of small alveoli during expiration by lowering surface tension.
Gastrointestinal system The primitive gut is present by the end of the fourth week. Between 5 and 6 weeks. The predominant phospholipid 80 per cent of the total is phosphatidylcholine lecithin. By 26 weeks. By 20 weeks the conductive airway tree and parallel vascular tree is well developed. It typically presents within the first few hours of life with signs of respiratory distress. Inadequate amounts of surfactant result in poor lung expansion and poor gas exchange. Failure of the gut to reenter the abdominal cavity results in the development of an omphalocele and this condition is associated with chromosomal anomaly Figure 4.
Without surgical intervention. Growth-restricted fetuses also have reduced glycogen stores and are therefore more prone to hypoglycaemia within the early neonatal period. Preterm infants have virtually no fat. For example. Atresias exist when there is a segment of bowel in which the lumen is not patent and are most commonly seen in the upper gastrointestinal tract.
The most common fistula is the tracheo-oesophageal fistula TOF. By the sixth week. Some babies with TOF also have other congenital anomalies. The large bowel is filled with meconium at term. Malrotation anomalies can result in volvulus and bowel obstruction. Peristalsis in the intestine occurs from the second trimester. Defecation in utero. Aspiration of meconium-stained liquor by the fetus at birth can result in meconium aspiration syndrome and respiratory distress.
In utero. This peaks at 12—16 weeks and continues until approximately 36 weeks. The larger portion of this diverticulum gives rise to the parenchymal cells hepatocytes and the hepatic ducts. This is aggravated by an incompletely developed alimentary system.
As the fetus continually swallows amniotic fluid. The liver and biliary tree appear late in the third week or early in the fourth week as the hepatic diverticulum.Glory Years Of Bath Rugby. From which complications are such severely growth-restricted infants particularly at risk? If facilities for transfer of women are available. In contrast, levels of alanine transaminase and aspartate transaminase have been shown to be lower in uncomplicated pregnancy when compared to non-pregnant levels.
It is also important that smears are not deferred in women who are at increased risk of cervical disease e.
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