A pre?x meaning before.
Example: precardiac (in front of the heart); prepatellar (in front of the patella).
The blood pressure is biphasic, being greatest (systolic pressure) at each heartbeat and falling (diastolic pressure) between beats. The average systolic pressure is around 100 mm Hg in children and 120 mm Hg in young adults, generally rising with age as the arteries get thicker and harder. Diastolic pressure in a healthy young adult is about 80 mm Hg, and a rise in diastolic pressure is often a surer indicator of HYPERTENSION than is a rise in systolic pressure; the latter is more sensitive to changes of body position and emotional mood. Hypertension has various causes, the most important of which are kidney disease (see KIDNEYS, DISEASES OF), genetic predisposition and, to some extent, mental stress. Systolic pressure may well be over 200 mm Hg. Abnormal hypertension is often accompanied by arterial disease (see ARTERIES, DISEASES OF) with an increased risk of STROKE, heart attack and heart failure (see HEART, DISEASES OF). Various ANTIHYPERTENSIVE DRUGS are available; these should be carefully evaluated, considering the patient’s full clinical history, before use.
HYPOTENSION may result from super?cial vasodilation (for example, after a bath, in fevers or as a side-e?ect of medication, particularly that prescribed for high blood pressure) and occur in weakening diseases or heart failure. The blood pressure generally falls on standing, leading to temporary postural hypotension – a particular danger in elderly people.... blood pressure
The haemagglutination inhibition test This, and the subsequent tests to be mentioned, are known as immunological tests. They are based upon the e?ect of the urine from a pregnant woman upon the interaction of red blood cells, which have been sensitised to human gonadotrophin, and anti-gonadotrophin serum. They have the great practical advantage of being performed in a test-tube or even on a slide. Because of their ease and speed of performance, a result can be obtained in two hours.
Enzyme-linked immunosorbent assay (ELISA) This is the basis of many of the pregnancy-testing kits obtainable from pharmacies. It is a highly sensitive antibody test and can detect very low concentrations of human chorionic gonadotrophin. Positive results show up as early as ten days after fertilisation – namely, four days before the ?rst missed period.
Ultrasound The fetal sac can be detected by ULTRASOUND from ?ve weeks, and a fetal echo at around six or seven weeks (see also PRENATAL SCREENING OR DIAGNOSIS).... pregnancy tests
The term is also used for the symptoms or signs with which a patient ?rst brings to a doctor.... presentation
There are 3 types of such conditions.
In the 1st, there are no tumours present but the condition carries an increased risk of cancer.
In the 2nd, there are noncancerous tumours that tend to become cancerous or are associated with the development of cancerous tumours elsewhere.
The 3rd type comprises disorders which have irregular features from the beginning but do not always become fully cancerous.... precancerous
The hormones may cause a premature growth spurt followed by early fusion of the bones. As a result, affected children may initially be tall but, if untreated, final height is often greatly reduced.
The child’s pattern of pubertal development is assessed by a doctor. Blood tests are performed to measure hormone levels. Ultrasound scanning of the ovaries and testes, and CT scanning of the adrenal glands or brain, may also be carried out, depending on the underlying cause suspected.
Treatment is of the underlying cause, and hormone drugs may be given to delay puberty and increase final height.... precocious puberty
A normal pregnancy lasts around 40 weeks from the first day of the woman’s last menstrual period. It is divided into 3 stages (trimesters) of 3 months each. For the first 8 weeks of pregnancy, the developing baby is called an embryo; thereafter it is called a fetus.
In the 1st trimester the breasts start to swell and may become tender. Morning sickness is common. The baby’s major organs have developed by the end of this stage. During the 2nd trimester, the mother’s nipples enlarge and darken and weight rises rapidly. The baby is usually felt moving by 22 weeks. During the 3rd trimester, stretch marks and colostrum may appear, and Braxton Hick’s contractions may be felt. The baby’s head engages at about 36 weeks.
Common, minor health problems during pregnancy include constipation, haemorrhoids, heartburn, pica, swollen ankles, and varicose veins. Other common disorders include urinary tract infections, stress incontinence (see incontinence, urinary), and candidiasis.Complications of pregnancy and disorders that affect it include antepartum haemorrhage; diabetic pregnancy; miscarriage; polyhydramnios; pre-eclampsia; prematurity; and Rhesus incompatibility. (See also childbirth; fetal heart monitoring; pregnancy, multiple.)... pregnancy
It consists of the encouragement of good oral hygiene, fluoride treatment, and scaling.... preventive dentistry
Habitat: Throughout the country, ascending to an altitude of about 1,050 m in the outer Himalayas.
English: Indian Wild Liquorice, Jequirity, Crab's Eye, Precatory Bean.Ayurvedic: Gunjaa, Gunjaka, Chirihintikaa, Raktikaa, Chirmi- ti, Kakanti, Kabjaka, Tiktikaa, Kaakananti, Kaakchinchi. (Not to be used as a substitute for liquorice.)Unani: Ghunghchi, Ghamchi.Siddha/Tamil: Kunri.Folk: Chirmiti, Ratti.Action: Uterine stimulant, abortifa- cient, toxic. Seeds—teratogenic. A paste of seeds is applied on vitiligo patches.
Along with other therapeutic applications, The Ayurvedic Pharmacopoeia of India has indicated the use of seeds in baldness.Seeds contain abrin, a toxalbumin, indole derivatives, anthocyanins, ste- rols, terpenes. Abrin causes agglutination of erythrocytes, haemolysis and enlargement of lymph glands. A non- toxic dose of abrin (1.25 mcg/kg body weight), isolated from the seeds of red var., exhibited a noticeable increase in antibody-forming cells, bone marrow cellularity and alpha-esterase-positive bone marrow cells.Oral administration of agglutinins, isolated from the seeds, is useful in the treatment of hepatitis and AIDS.The seed extract exhibited antischis- tosomal activity in male hamsters.The methanolic extract of seeds inhibited the motility of human spermatozoa.The roots contain precol, abrol, gly- cyrrhizin (1.5%) and alkaloids—abra- sine and precasine. The roots also contain triterpenoids—abruslactone A, methyl abrusgenate and abrusgenic acid.Alkaloids/bases present in the roots are also present in leaves and stems.A. fruticulosus Wall. Ex Wight and Arn. synonym A. pulchellus Wall., A. laevigatus E. May. (Shveta Gunjaa) is also used for the same medicinal purposes as A. precatorius.Dosage: Detoxified seed—1-3 g powder. Root powder—3-6 g. (API Vols. I, II.)... abrus precatoriusThe other dangers of administering drugs in pregnancy are the teratogenic effects (see TERATOGENESIS). It is understandable that a drug may interfere with a mechanism essential for growth and result in arrested or distorted development of the fetus and yet cause no disturbance in the adult, in whom these di?erentiation and organisation processes have ceased to be relevant. Thus the e?ect of a drug upon a fetus may di?er qualitatively as well as quantitatively from its e?ect on the mother. The susceptibility of the embryo will depend on the stage of development it has reached when the drug is given. The stage of early di?erentiation – that is, from the beginning of the third week to the end of the tenth week of pregnancy – is the time of greatest susceptibility. After this time the risk of congenital malformation from drug treatment is less, although the death of the fetus can occur at any time.... drugs in pregnancy
For more prolonged arti?cial ventilation it is usual to use a specially designed machine or ventilator to perform the task. The ventilators used in operating theatres when patients are anaesthetised and paralysed are relatively simple devices.They often consist of bellows which ?ll with fresh gas and which are then mechanically emptied (by means of a weight, piston, or compressed gas) via a circuit or tubes attached to an endotracheal tube into the patient’s lungs. Adjustments can be made to the volume of fresh gas given with each breath and to the length of inspiration and expiration. Expiration is usually passive back to the atmosphere of the room via a scavenging system to avoid pollution.
In intensive-care units, where patients are not usually paralysed, the ventilators are more complex. They have electronic controls which allow the user to programme a variety of pressure waveforms for inspiration and expiration. There are also programmes that allow the patient to breathe between ventilated breaths or to trigger ventilated breaths, or inhibit ventilation when the patient is breathing.
Indications for arti?cial ventilation are when patients are unable to achieve adequate respiratory function even if they can still breathe on their own. This may be due to injury or disease of the central nervous, cardiovascular, or respiratory systems, or to drug overdose. Arti?cial ventilation is performed to allow time for healing and recovery. Sometimes the patient is able to breathe but it is considered advisable to control ventilation – for example, in severe head injury. Some operations require the patient to be paralysed for better or safer surgical access and this may require ventilation. With lung operations or very unwell patients, ventilation is also indicated.
Arti?cial ventilation usually bypasses the physiological mechanisms for humidi?cation of inspired air, so care must be taken to humidify inspired gases. It is important to monitor the e?cacy of ventilation – for example, by using blood gas measurement, pulse oximetry, and tidal carbon dioxide, and airways pressures.
Arti?cial ventilation is not without its hazards. The use of positive pressure raises the mean intrathoracic pressure. This can decrease venous return to the heart and cause a fall in CARDIAC OUTPUT and blood pressure. Positive-pressure ventilation may also cause PNEUMOTHORAX, but this is rare. While patients are ventilated, they are unable to breathe and so accidental disconnection from the ventilator may cause HYPOXIA and death.
Negative-pressure ventilation is seldom used nowadays. The chest or whole body, apart from the head, is placed inside an airtight box. A vacuum lowers the pressure within the box, causing the chest to expand. Air is drawn into the lungs through the mouth and nose. At the end of inspiration the vacuum is stopped, the pressure in the box returns to atmospheric, and the patient exhales passively. This is the principle of the ‘iron lung’ which saved many lives during the polio epidemics of the 1950s. These machines are cumbersome and make access to the patient di?cult. In addition, complex manipulation of ventilation is impossible.
Jet ventilation is a relatively modern form of ventilation which utilises very small tidal volumes (see LUNGS) from a high-pressure source at high frequencies (20–200/min). First developed by physiologists to produce low stable intrathoracic pressures whilst studying CAROTID BODY re?exes, it is sometimes now used in intensive-therapy units for patients who do not achieve adequate gas exchange with conventional ventilation. Its advantages are lower intrathoracic pressures (and therefore less risk of pneumothorax and impaired venous return) and better gas mixing within the lungs.... intermittent positive pressure (ipp)
Pregnancy lasts about 280 days and is calculated from the ?rst day of the last menstrual period – see MENSTRUATION. Pregnancy-testing kits rely on the presence of the hormone beta HUMAN CHORIONIC GONADOTROPHIN (b HCG) which is excreted in the woman’s urine as early as 30 days from the last menstrual period. The estimated date of delivery can be accurately estimated from the size of the developing fetus measured by ULTRASOUND (see also below) between seven and 24 weeks. ‘Term’ refers to the time that the baby is due; this can range from 38 weeks to 41 completed weeks.
Physical changes occur in early pregnancy – periods stop and the abdomen enlarges. The breasts swell, with the veins becoming prominent and the nipples darkening. About two in three women will have nausea with a few experiencing such severe vomiting as to require hospital admission for rehydration.
Antenatal care The aim of antenatal care is to ensure a safe outcome for both mother and child; it is provided by midwives (see MIDWIFE) and doctors. Formal antenatal care began in Edinburgh in the 1930s with the recognition that all aspects of pregnancy – normal and abnormal – warranted surveillance. Cooperation between general practitioners, midwives and obstetricians is now established, with pregnancies that are likely to progress normally being cared for in the community and only those needing special intervention being cared for in a hospital setting.
The initial visit (or booking) in the ?rst half of pregnancy will record the history of past events and the results of tests, with the aim of categorising the patients into normal or not. Screening tests including blood checks and ultrasound scans are a routine part of antenatal care. The ?rst ultrasound scan is done at about 11 weeks to date the pregnancy, with a further one done at 20 weeks – the anomaly scan – to assess the baby’s structure. Some obstetric units will check the growth of the baby with one further scan later in the pregnancy or, in the case of twin pregnancies (see below), many scans throughout. The routine blood tests include checks for ANAEMIA, DIABETES MELLITUS, sickle-cell disease and THALASSAEMIA, as well as for the blood group. Evidence of past infections is also looked for; tests for RUBELLA (German measles) and SYPHILIS are routine, whereas tests for human immunode?ciency virus (see AIDS/ HIV below) and HEPATITIS are being o?ered as optional, although there is compelling evidence that knowledge of the mother’s infection status is bene?cial to the baby.
Traditional antenatal care consists of regular appointments, initially every four weeks until 34 weeks, then fortnightly or weekly. At each visit the mother’s weight, urine and blood pressure are checked, and assessment of fetal growth and position is done by palpating the uterus. Around two-thirds of pregnancies and labours are normal: in the remainder, doctors and midwives need to increase the frequency of surveillance so as to prevent or deal with maternal and fetal problems.
Common complications of pregnancy
Some of the more common complications of pregnancy are listed below.
As well as early detection of medical complications, antenatal visits aim to be supportive and include emotional and educational care. Women with uncomplicated pregnancies are increasingly being managed by midwives and general practitioners in the community and only coming to the hospital doctors should they develop a problem. A small number will opt for a home delivery, but facilities for providing such a service are not always available in the UK.
Women requiring more intensive surveillance have their management targeted to the speci?c problems encountered. Cardiologists will see mothers-to-be with heart conditions, and those at risk of diabetes are cared for in designated clinics with specialist sta?. Those women needing more frequent surveillance than standard antenatal care can be looked after in maternity day centres. These typically include women with mildly raised blood pressure or those with small babies. Fetal medicine units have specialists who are highly skilled in ultrasound scanning and specialise in the diagnosis and management of abnormal babies still in the uterus. ECTOPIC PREGNANCY Chronic abdominal discomfort early in pregnancy may be caused by unruptured ectopic pregnancy, when, rarely, the fertilised OVUM starts developing in the Fallopian tube (see FALLOPIAN TUBES) instead of the uterus. The patient needs hospital treatment and LAPAROSCOPY. A ruptured ectopic pregnancy causes acute abdominal symptoms and collapse, and the woman will require urgent abdominal surgery. URINARY TRACT INFECTIONS These affect around 2 per cent of pregnant women and are detected by a laboratory test of a mid-stream specimen of urine. In pregnancy, symptoms of these infections do not necessarily resemble those experienced by non-pregnant women. As they can cause uterine irritability and possible premature labour (see below), it is important to ?nd and treat them appropriately. ANAEMIA is more prevalent in patients who are vegetarian or on a poor diet. Iron supplements are usually given to women who have low concentrations of HAEMOGLOBIN in their blood (less than 10.5 g/dl) or who are at risk of becoming low in iron, from bleeding, twin pregnancies and those with placenta previa (see below). ANTEPARTUM HAEMORRHAGE Early in pregnancy, vaginal bleedings may be due to a spontaneous or an incomplete therapeutic ABORTION. Bleeding from the genital tract between 24 completed weeks of pregnancy and the start of labour is called antepartum haemorrhage. The most common site is where the PLACENTA is attached to the wall of the uterus. If the placenta separates before delivery, bleeding occurs in the exposed ‘bed’. When the placenta is positioned in the upper part of the uterus it is called an abruption. PLACENTA PRAEVIA is sited in the lower part and blocks or partly blocks the cervix (neck of the womb); it can be identi?ed at about the 34th week. Ten per cent of episodes of antepartum bleeding are caused by placenta previa, and it may be associated with bleeding at delivery. This potentially serious complication is diagnosed by ultrasound scanning and may require a caesarean section (see below) at delivery. INCREASED BLOOD PRESSURE, associated with protein in the urine and swelling of the limbs, is part of a condition known as PRE-ECLAMPSIA. This occurs in the second half of pregnancy in about 1 in 10 women expecting their ?rst baby, and is mostly very mild and of no consequence to the pregnancy. However, some women can develop extremely high blood pressures which can adversely affect the fetus and cause epileptic-type seizures and bleeding disorders in the mother. This serious condition is called ECLAMPSIA. For this reason a pregnant woman with raised blood pressure or PROTEIN in her urine is carefully evaluated with blood tests, often in the maternity day assessment unit. The condition can be stopped by delivery of the baby, and this will be done if the mother’s or the fetus’s life is in danger. If the condition is milder, and the baby not mature enough for a safe delivery, then drugs can be used to control the blood pressure. MISCARRIAGE Also called spontaneous abortion, miscarriage is the loss of the fetus. There are several types:
threatened miscarriage is one in which some vaginal bleeding occurs, the uterus is enlarged, but the cervix remains closed and pregnancy usually proceeds.
inevitable miscarriage usually occurs before the 16th week and is typi?ed by extensive blood loss through an opened cervix and cramp-like abdominal pain; some products of conception are lost but the developing placental area (decidua) is retained and an operation may be necessary to clear the womb.
missed miscarriages, in which the embryo dies and is absorbed, but the decidua (placental area of uterine wall) remains and may cause abdominal discomfort and discharge of old blood.
THERAPEUTIC ABORTION is performed on more than 170,000 women annually in England and Wales. Sometimes the woman may not have arranged the procedure through the usual health-care channels, so that a doctor may see a patient with vaginal bleeding, abdominal discomfort or pain, and open cervix – symptoms which suggest that the decidua and a blood clot have been retained; these retained products will need to be removed by curettage.
Septic abortions are now much less common in Britain than before the Abortion Act (1967) permitted abortion in speci?ed circumstances. The cause is the passage of infective organisms from the vagina into the uterus, with Escherichia coli and Streptococcus faecalis the most common pathogenic agents. The woman has abdominal pain, heavy bleeding, usually fever and sometimes she is in shock. The cause is usually an incomplete abortion or one induced in unsterile circumstances. Antibiotics and curettage are the treatment. INTRAUTERINE GROWTH RETARDATION describes a slowing of the baby’s growth. This can be diagnosed by ultrasound scanning, although there is a considerable margin of error in estimates of fetal weight. Trends in growth are favoured over one-o? scan results alone. GESTATIONAL DIABETES is a condition that is more common in women who are overweight or have a family member with diabetes. If high concentrations of blood sugar are found, e?orts are made to correct it as the babies can become very fat (macrosomia), making delivery more di?cult. A low-sugar diet is usually enough to control the blood concentration of sugars; however some women need small doses of INSULIN to achieve control. FETAL ABNORMALITIES can be detected before birth using ultrasound. Some of these defects are obvious, such as the absence of kidneys, a condition incompatible with life outside the womb. These women can be o?ered a termination of their pregnancy. However, more commonly, the pattern of problems can only hint at an abnormality and closer examination is needed, particularly in the diagnosis of chromosomal deformities such as DOWN’S (DOWN) SYNDROME (trisomy 21 or presence of three 21 chromosomes instead of two).
Chromosomal abnormalities can be de?nitively diagnosed only by cell sampling such as amniocentesis (obtaining amniotic ?uid – see AMNION – from around the baby) done at 15 weeks onwards, and chorionic villus sampling (sampling a small part of the placenta) – another technique which can be done from 12 weeks onwards. Both have a small risk of miscarriage associated with them; consequently, they are con?ned to women at higher risk of having an abnormal fetus.
Biochemical markers present in the pregnant woman’s blood at di?erent stages of pregnancy may have undergone changes in those carrying an abnormal fetus. The ?rst such marker to be routinely used was a high concentration of alpha-fetol protein in babies with SPINA BIFIDA (defects in the covering of the spinal cord). Fuller research has identi?ed a range of diagnostic markers which are useful, and, in conjunction with other factors such as age, ethnic group and ultrasound ?ndings, can provide a predictive guide to the obstetrician – in consultation with the woman – as to whether or not to proceed to an invasive test. These tests include pregnancy-associated plasma protein assessed from a blood sample taken at 12 weeks and four blood tests at 15–22 weeks – alphafetol protein, beta human chorionic gonadotrophin, unconjugated oestriol and inhibin A. Ultrasound itself can reveal physical ?ndings in the fetus, which can be more common in certain abnormalities. Swelling in the neck region of an embryo in early pregnancy (increased nuchal thickness) has good predictive value on its own, although its accuracy is improved in combination with the biochemical markers. The e?ectiveness of prenatal diagnosis is rapidly evolving, the aim being to make the diagnosis as early in the pregnancy as possible to help the parents make more informed choices. MULTIPLE PREGNANCIES In the UK, one in 95 deliveries is of twins, while the prevalence of triplets is one in 10,000 and quadruplets around one in 500,000. Racial variations occur, with African women having a prevalence rate of one in 30 deliveries for twins and Japanese women a much lower rate than the UK ?gure. Multiple pregnancies occur more often in older women, and in the UK the prevalence of fertility treatments, many of these being given to older women, has raised the incidence. There is now an o?cial limit of three eggs being transferred to a woman undergoing ASSISTED CONCEPTION (gamete intrafallopian transfer, or GIFT).
Multiple pregnancies are now usually diagnosed as a result of routine ultrasound scans between 16 and 20 weeks of pregnancy. The increased size of the uterus results in the mother having more or worse pregnancy-related conditions such as nausea, abdominal discomfort, backache and varicose veins. Some congenital abnormalities in the fetus occur more frequently in twins: NEURAL TUBE defects, abnormalities of the heart and the incidence of TURNER’S SYNDROME and KLINEFELTER’S SYNDROME are examples. Such abnormalities may be detected by ultrasound scans or amniocentesis. High maternal blood pressure and anaemia are commoner in women with multiple pregnancies (see above).
The growth rates of multiple fetuses vary, but the di?erence between them and single fetuses are not that great until the later stages of pregnancy. Preterm labour is commoner in multiple pregnancies: the median length of pregnancy is 40 weeks for singletons, 37 for twins and 33 for triplets. Low birth-weights are usually the result of early delivery rather than abnormalities in growth rates. Women with multiple pregnancies require more frequent and vigilant antenatal assessments, with their carers being alert to the signs of preterm labour occurring. CEPHALOPELVIC DISPROPORTION Disparity between the size of the fetus and the mother’s pelvis is not common in the UK but is a signi?cant problem in the developing world. Disparity is classi?ed as absolute, when there is no possibility of delivery, and relative, when the baby is large but delivery (usually after a dif?cult labour) is possible. Causes of absolute disparity include: a large baby – heavier than 5 kg at birth; fetal HYDROCEPHALUS; and an abnormal maternal pelvis. The latter may be congenital, the result of trauma or a contraction in pelvic size because of OSTEOMALACIA early in life. Disproportion should be suspected if in late pregnancy the fetal head has not ‘engaged’ in the pelvis. Sometimes a closely supervised ‘trial of labour’ may result in a successful, if prolonged, delivery. Otherwise a caesarean section (see below) is necessary. UNUSUAL POSITIONS AND PRESENTATIONS OF THE BABY In most pregnant women the baby ?ts into the maternal pelvis head-?rst in what is called the occipito-anterior position, with the baby’s face pointing towards the back of the pelvis. Sometimes, however, the head may face the other way, or enter the pelvis transversely – or, rarely, the baby’s neck is ?exed backwards with the brow or face presenting to the neck of the womb. Some malpositions will correct naturally; others can be manipulated abdominally during pregnancy to a better position. If, however, the mother starts labour with the baby’s head badly positioned or with the buttocks instead of the head presenting (breech position), the labour will usually be longer and more di?cult and may require intervention using special obstetric forceps to assist in extracting the baby. If progress is poor and the fetus distressed, caesarean section may be necessary. HIV INFECTION Pregnant women who are HIV positive (see HIV; AIDS/HIV) should be taking antiviral drugs in the ?nal four to ?ve months of pregnancy, so as to reduce the risk of infecting the baby in utero and during birth by around 50 per cent. Additional antiviral treatment is given before delivery; the infection risk to the baby can be further reduced – by about 40 per cent – if delivery is by caesarean section. The mother may prefer to have the baby normally, in which case great care should be taken not to damage the baby’s skin during delivery. The infection risk to the baby is even further reduced if it is not breast fed. If all preventive precautions are taken, the overall risk of the infant becoming infected is cut to under 5 per cent.
Premature birth This is a birth that takes place before the end of the normal period of gestation, usually before 37 weeks. In practice, however, it is de?ned as a birth that takes place when the baby weighs less than 2·5 kilograms (5••• pounds). Between 5 and 10 per cent of babies are born prematurely, and in around 40 per cent of premature births the cause is unknown. Pre-eclampsia is the most common known cause; others include hypertension, chronic kidney disease, heart disease and diabetes mellitus. Multiple pregnancy is another cause. In the vast majority of cases the aim of management is to prolong the pregnancy and so improve the outlook for the unborn child. This consists essentially of rest in bed and sedation, but there are now several drugs, such as RITODRINE, that may be used to suppress the activity of the uterus and so help to delay premature labour. Prematurity was once a prime cause of infant mortality but modern medical care has greatly improved survival rates in developing countries.
Labour Also known by the traditional terms parturition, childbirth or delivery, this is the process by which the baby and subsequently the placenta are expelled from the mother’s body. The onset of labour is often preceded by a ‘show’ – the loss of the mucus and blood plug from the cervix, or neck of the womb; this passes down the vagina to the exterior. The time before the beginning of labour is called the ‘latent phase’ and characteristically lasts 24 hours or more in a ?rst pregnancy. Labour itself is de?ned by regular, painful contractions which cause dilation of the neck of the womb and descent of the fetal head. ‘Breaking of the waters’ is the loss of amniotic ?uid vaginally and can occur any time in the delivery process.
Labour itself is divided into three stages: the ?rst is from the onset of labour to full (10 cm) dilation of the neck of the womb. This stage varies in length, ideally taking no more than one hour per centimetre of dilation. Progress is monitored by regular vaginal examinations, usually every four hours. Fetal well-being is observed by intermittent or continuous monitoring of the fetal heart rate in relation to the timing and frequency of the contractions. The print-out is called a cardiotocograph. Abnormalities of the fetal heart rate may suggest fetal distress and may warrant intervention. In women having their ?rst baby (primigravidae), the common cause of a slow labour is uncoordinated contractions which can be overcome by giving either of the drugs PROSTAGLANDIN or OXYTOCIN, which provoke contractions of the uterine muscle, by an intravenous drip. Labours which progress slowly or not at all may be due to abnormal positioning of the fetus or too large a fetus, when prostaglandin or oxytocin is used much more cautiously.
The second stage of labour is from full cervical dilation to the delivery of the baby. At this stage the mother often experiences an irresistible urge to push the baby out, and a combination of strong coordinated uterine contractions and maternal e?ort gradually moves the baby down the birth canal. This stage usually lasts under an hour but can take longer. Delay, exhaustion of the mother or distress of the fetus may necessitate intervention by the midwife or doctor. This may mean enlarging the vaginal opening with an EPISIOTOMY (cutting of the perineal outlet – see below) or assisting the delivery with specially designed obstetric forceps or a vacuum extractor (ventouse). If the cervix is not completely dilated or open and the head not descended, then an emergency caesarean section may need to be done to deliver the baby. This procedure involves delivering the baby and placenta through an incision in the mother’s abdomen. It is sometimes necessary to deliver by planned or elective caesarean section: for example, if the placenta is low in the uterus – called placenta praevia – making a vaginal delivery dangerous.
The third stage occurs when the placenta (or afterbirth) is delivered, which is usually about 10–20 minutes after the baby. An injection of ergometrine and oxytocin is often given to women to prevent bleeding.
Pain relief in labour varies according to the mother’s needs. For uncomplicated labours, massage, reassurance by a birth attendant, and a warm bath and mobilisation may be enough for some women. However, some labours are painful, particularly if the woman is tired or anxious or is having her ?rst baby. In these cases other forms of analgesia are available, ranging from inhalation of NITROUS OXIDE GAS, injection of PETHIDINE HYDROCHLORIDE or similar narcotic, and regional local anaesthetic (see ANAESTHESIA).
Once a woman has delivered, care continues to ensure her and the baby’s safety. The midwives are involved in checking that the uterus returns to its normal size and that there is no infection or heavy bleeding, as well as caring for stitches if needed. The normal blood loss after birth is called lochia and generally is light, lasting up to six weeks. Midwives o?er support with breast feeding and care of the infant and will visit the parents at home routinely for up to two weeks.
Some complications of labour All operative deliveries in the UK are now done in hospitals, and are performed if a spontaneous birth is expected to pose a bigger risk to the mother or her child than a specialist-assisted one. Operative deliveries include caesarean section, forceps-assisted deliveries and those in which vacuum extraction (ventouse) is used. CAESAREAN SECTION Absolute indications for this procedure, which is used to deliver over 15 per cent of babies in Britain, are cephalopelvic disproportion and extensive placenta praevia, both discussed above. Otherwise the decision to undertake caesarean section depends on the clinical judgement of the specialist and the views of the mother. The rise in the proportion of this type of intervention (from 5 per cent in the 1930s to its present level of over 23 per cent
P
of the 600,000 or so annual deliveries in England) has been put down to defensive medicine
– namely, the doctor’s fear of litigation (initiated often because the parents believe that the baby’s health has suffered because the mother had an avoidably di?cult ‘natural’ labour). In Britain, over 60 per cent of women who have had a caesarean section try a vaginal delivery in a succeeding pregnancy, with about two-thirds of these being successful. Indications for the operation include:
absolute and relative cephalopelvic disproportion.
placenta previa.
fetal distress.
prolapsed umbilical cord – this endangers the viability of the fetus because the vital supply of oxygen and nutrients is interrupted.
malpresentation of the fetus such as breech or transverse lie in the womb.
unsatisfactory previous pregnancies or deliveries.
a request from the mother.
Caesarean sections are usually performed using regional block anaesthesia induced by a spinal or epidural injection. This results in loss of feeling in the lower part of the body; the mother is conscious and the baby not exposed to potential risks from volatile anaesthetic gases inhaled by the mother during general anaesthesia. Post-operative complications are higher with general anaesthesia, but maternal anxiety and the likelihood that the operation might be complicated and di?cult are indications for using it. A general anaesthetic may also be required for an acute obstetric emergency. At operation the mother’s lower abdomen is opened and then her uterus opened slowly with a transverse incision and the baby carefully extracted. A transverse incision is used in preference to the traditional vertical one as it enables the woman to have a vaginal delivery in any future pregnancy with a much smaller risk of uterine rupture. Women are usually allowed to get up within 24 hours and are discharged after four or ?ve days. FORCEPS AND VENTOUSE DELIVERIES Obstetric forceps are made in several forms, but all are basically a pair of curved blades shaped so that they can obtain a purchase on the baby’s head, thus enabling the operator to apply traction and (usually) speed up delivery. (Sometimes they are used to slow down progress of the head.) A ventouse or vacuum extractor comprises an egg-cup-shaped metal or plastic head, ranging from 40 to 60 mm in diameter with a hollow tube attached through which air is extracted by a foot-operated vacuum pump. The instrument is placed on the descending head, creating a negative pressure on the skin of the scalp and enabling the operator to pull the head down. In mainland Europe, vacuum extraction is generally preferred to forceps for assisting natural deliveries, being used in around 5 per cent of all deliveries. Forceps have a greater risk of causing damage to the baby’s scalp and brain than vacuum extraction, although properly used, both types should not cause any serious damage to the baby.
Episiotomy Normal and assisted deliveries put the tissues of the genital tract under strain. The PERINEUM is less elastic than the vagina and, if it seems to be splitting as the baby’s head
moves down the birth canal, it may be necessary to cut the perineal tissue – a procedure called an episiotomy – to limit damage. This is a simple operation done under local anaesthetic. It should be done only if there is a speci?c indication; these include:
to hasten the second stage of labour if the fetus is distressed.
to facilitate the use of forceps or vacuum extractor.
to enlarge a perineum that is restricted because of unyielding tissue, perhaps because of a scar from a previous labour. Midwives as well as obstetricians are trained
to undertake and repair (with sutures) episiotomies.
(For organisations which o?er advice and information on various aspects of childbirth, including eclampsia, breast feeding and multiple births, see APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELF-HELP.)... pregnancy and labour
Habitat: The sub-tropical Himalayas and in Assam, extending southwards through West Bengal, Bihar, Orissa into Deccan Peninsula. Roots are usually confused with those of Clerodendrum serratum and are sold as Bhaarangi.
Siddha/Tamil: Siru Thekku.Folk: Gethiaa, Ghantu Bhaarangi. Baaman-haati (Bengal). Fruits are known as Bhuumi-jambu, Phin Jaamun. The root is known as Bhaarangamuula; in Andhra Pradesh, Gandu Bhaarangi.Action: Root and leaves—given in asthma, rheumatism.
The root contains several diterpe- noids. Quinonemethide (bharangin) is reported from the plant. controlling the activity of the adreno- corticotropic hormone.Dosage: Leaf, root bark—50- 100 ml decoction, powder—1-3 g. (CCRAS.)... premna herbaceaHabitat: Indian and Andaman Coasts, plains of Assam and Khasi hills.
English: Headache tree.Ayurvedic: Agnimantha (Kerala), Shriparni, Jayee, Ganikaarikaa, Vaataghni.Siddha/Tamil: MunnaiFolk: Agethaa, Ganiyaari.Action: Carminative, galactagogue. The tender plant is used for neuralgia and rheumatism. A decoction of leaves is used for flatulence and colic.
Aqueous extracts of the plant showed a powerful action on the uterus and gout of the experimental animals, causing a marked increase in their activity.The leaves contain an isoxazole alkaloid premnazole, which was found to reduce granuloma formation in rats (34.62%), its activity was comparable to phenylbutazone (35-36%).Premnazole also reduced GPT and GOT in serum and liver. Studies suggest that premnazole acts probably byFamily: Verbenaceae.Habitat: Peninsular India, Bihar, West Bengal and North-eastern India.
English: Dusky Fire Brand Bark.Ayurvedic: Agnimantha (var.).Siddha/Tamil: Pachumullai, Erumai munnai.Folk: Agethu (var.).Action: Leaves—diuretic, spasmolytic. Stem bark—hypoglycaemic.
The leaves gave a furanoid, prem- nalatin, and flavone glycosides. The stem bark gave iridoid glucosides and geniposidic acid.Premna latifolia var. mucronata C. B. Clarke and Premna barbata Wall. are known as Bakaar and Basota (in Garh- wal). These have been equated with the classical herb Vasuhatta.... premna integrifoliaHabitat: Peninsular India and Bihar up to 1,200 m.
English: Bastard Teak.Ayurvedic: Agnimanth (var.).Siddha/Tamil: Kolakottathekku pinari, Pondanganari.Folk: Gineri (var.).Action: Bark and essential oil of root—used in stomach disorders. Leaf—diuretic, vulnerary; prescribed as a tonic after child birth; used in dropsical affections. Pounded leaves—vulnerary.
The heartwood gave apigenin derivatives. The leaves gave essential oil containing d-and dl-limonene, beta- caryophyllene a sesquiterpene hydrocarbon, a diterpene hydrocarbon and a sesquiterpene tertiary alcohol.The roots and rhizomes of P. veris and P. elatior contain a saponin, yielding a sapogenin, primulagenin A. A fla- vonol glycoside named primulaflavo- noloside has been reported in the flowers of P. veris. The root of P. veris are considered as a substitute for Senega (Polygala senega) roots.Anthocyanidins have been detected in most of the Primula species, also a highly toxic allergenic substance, primin, in the leaves and glandular hairs. The floral and foliar parts of the different genotypes showed presence of kaempferol, quercetin and myricetin.... premna tomentosaULTRASOUND scanning is probably the most widely used diagnostic tool in obstetric practice. It can detect structural abnormalities such as SPINA BIFIDA and CLEFT PALATE and even cardiac and renal problems. A series of scans can assess whether the baby is growing at a normal rate; ultrasound may also be used to assist with other diagnostic tests (e.g. AMNIOCENTESIS – see below).
Tests on the mother’s blood can also diagnose fetal abnormalities. Alphafetoprotein (AFP) is produced by babies and ‘leaks’ into the AMNIOTIC FLUID and is absorbed by the mother. In spina bi?da and other neural-tube defects there is increased leakage of AFP, and a blood test at 16 weeks’ gestation can detect a raised level which suggests the presence of these abnormalities.
The triple test, also performed at 16 weeks, measures AFP and two hormones – HUMAN CHORIONIC GONADOTROPHIN and unconjugated OESTRADIOL – and is used in diagnosing DOWN’S (DOWN) SYNDROME.
Amniocentesis involves inserting a needle through the mother’s abdominal wall into the uterus to remove a sample of amniotic ?uid at 16–18 weeks. Examination of the ?uid and the cells it contains is used in the diagnosis of Down’s syndrome and other inherited disorders. The test carries a small risk of miscarriage.
Chorionic villus sampling may be used to diagnose various inherited conditions. A small amount of tissue from the developing PLACENTA is removed for analysis: this test has the advantages of having a lower incidence of miscarriage than amniocentesis and is carried out at an earlier stage (9–13 weeks).
Analysis of a blood sample removed from the umbilical cord (cordocentesis) may diagnose infections in the uterus, blood disorders or inherited conditions.
Direct observation of the fetus via a viewing instrument called a fetoscope is also used diagnostically and will detect structural abnormalities.
Most tests have a recognised incidence of false positive and negative results and are therefore usually cross-checked with another test. Counselling of the parents about prenatal tests is important. This allows them to make an informed choice which may not necessarily involve terminating the pregnancy if an abnormality is found. (See PREGNANCY AND LABOUR.)... prenatal screening or diagnosis
Presenciah, Presencea, Presenceah, Presenciya, Presenciyah... presencia
Haemophilus vaccine (HiB) This vaccine was introduced in the UK in 1994 to deal with the annual incidence of about 1,500 cases and 100 deaths from haemophilus MENINGITIS, SEPTICAEMIA and EPIGLOTTITIS, mostly in pre-school children. It has been remarkably successful when given as part of the primary vaccination programme at two, three and four months of age – reducing the incidence by over 95 per cent. A few cases still occur, either due to other subgroups of the organism for which the vaccine is not designed, or because of inadequate response by the child, possibly related to interference from the newer forms of pertussis vaccine (see above) given at the same time.
Meningococcal C vaccine Used in the UK from 1998, this has dramatically reduced the incidence of meningitis and septicaemia due to this organism. Used as part of the primary programme in early infancy, it does not protect against other types of meningococci.
Varicella vaccine This vaccine, used to protect against varicella (CHICKENPOX) is used in a number of countries including the United States and Japan. It has not been introduced into the UK, largely because of concerns that use in infancy would result in an upsurge in cases in adult life, when the disease may be more severe.
Pneumococcal vaccine The pneumococcus is responsible for severe and sometimes fatal childhood diseases including meningitis and septicaemia, as well as PNEUMONIA and other respiratory infections. Vaccines are available but do not protect against all strains and are reserved for special situations – such as for patients without a SPLEEN or those who are immunode?cient.... yellow fever vaccine is prepared from
This operation was formerly used to treat severe psychiatric disorders; it is very rarely performed now.... lobotomy, prefrontal
uterus (an invasive mole). A molar pregnancy that becomes cancerous is called a choriocarcinoma.
If the dead embryo and placenta are not expelled from the uterus after a miscarriage, the dead tissue is called a carneous mole.... molar pregnancy
Alternatives. Tea: equal parts – Agnus Castus, Ladysmantle, Motherwort, Raspberry leaves, 1-2 teaspoon to each cup boiling water; infuse 5-10 minutes; 1 cup 2-3 times daily.
Tablets/capsules. Cramp bark, Helonias.
Powders. Formula. Combine Blue Cohosh 1; Helonias 2; Black Haw 3. Dose: 500mg (two 00 capsules or one-third teaspoon) thrice daily.
Practitioner. Tincture Viburnum prunifolium BHP (1983), 20ml; Tincture Chamaelirium luteum BHP (1983) 20ml; Tincture Viburnum opulus BHP (1983), 20ml; Tincture Capsicum, fort, BPC 1934, 0.05ml. Distilled water to 100ml. Sig: 5ml tds pc c Aq cal.
Black Cohosh. Liquid Extract Cimicifuja BP 1898, 1:1 in 90 per cent alcohol. Dosage: 0.3-2ml. OR: Tincture Cimicifuja, BPC 1934, 1:10 in 60 per cent alcohol. Dosage: 2-4ml.
Squaw Vine (mother’s cordial) is specific for habitual abortion, beginning soon after becoming pregnant and continuing until the seventh month. Also the best remedy when abortion threatens. If attended by a physician for abortion, a hypodermic of morphine greatly assists; followed by Liquid Extract 1:1 Squaw Vine. Dosage: 2-4ml, 3 times daily.
Liquid extracts. Squaw Vine, 4 . . . Helonias, 1 . . . Black Haw bark, 1 . . . Blue Cohosh, 1. Mix. Dose: One teaspoon every 2 hours for 10 days. Thereafter: 2 teaspoons before meals, 3 times daily. Honey to sweeten, if necessary. (Dr Finlay Ellingwood)
Abortion, to prevent: Cramp bark, (Dr John Christopher)
Evening Primrose. Two 500mg capsules, at meals thrice daily.
Diet: High protein.
Vitamins. C. B6. Multivitamins. E (400iu daily).
Minerals. Calcium. Iodine. Iron. Selenium, Zinc. Magnesium deficiency is related to history of spontaneous abortion; magnesium to commence as soon as pregnant.
Enforced bed rest. ... abortion – to prevent
Gestational diabetes is usually detected in the second half of pregnancy.
The mother does not produce enough insulin to keep blood glucose levels normal.
True gestational diabetes disappears with the delivery of the baby but is associated with an increased risk of developing type 2 diabetes in later life.... diabetic pregnancy
less fluid is produced and the eye becomes soft.... intraocular pressure
may involve counselling or psychotherapy. (See also conversion disorder.)... pregnancy, false
Twins occur in about 1 in 80 pregnancies, triplets in about 1 in 8,000, and quadruplets in about 1 in 73,000.
Multiple pregnancies are more common in women who are treated with fertility drugs or if a number of fertilized ova are implanted during in vitro fertilization.... pregnancy, multiple
Prescription-only medicines are those whose safe use is difficult to ensure without medical supervision.... prescription-only medicine
Problems may also be caused in a developing baby if a pregnant woman drinks alcohol, smokes (see tobaccosmoking), or takes drugs of abuse. The babies of women who use heroin during pregnancy tend to have a low birthweight and a higher death rate than normal during the first few weeks of life. Babies of women who abuse drugs intravenously are at high risk of HIV infection.... pregnancy, drugs in
Some 40 per cent of premature deliveries occur for no known reason. The remainder are due to conditions such as pre-eclampsia, hypertension, diabetes mellitus, long-standing kidney disease, and heart disease. Other causes are antepartum haemorrhage, intrauterine infection, or premature rupture of membranes. A common cause is multiple pregnancy (see pregnancy, multiple).
A premature infant is smaller than a full-term baby, lacks subcutaneous fat, is covered with downy hair (lanugo), and has very thin skin. The baby’s internal organs are also immature. The major complication is respiratory distress syndrome. There is increased risk of brain haemorrhage, jaundice, and hypoglycaemia. The baby has a limited ability to suck and maintain body temperature, and is prone to infection. The earlier a baby is born, the more likely it is to have such problems.
Premature infants are usually nursed in a special baby unit that provides intensive care. The baby is placed in an incubator, and may have artificial ventilation to assist breathing, artificial feeding through a stomach tube or into a vein, and treatment with antibiotic drugs and iron and vitamin supplements. With modern techniques, some infants survive even if they are born as early as 24 weeks’ gestation.... prematurity
In rare cases, the vomiting becomes severe and prolonged. This can cause dehydration, nutritional deficiency, alterations in blood acidity, and weight loss. Immediate hospital admission is then required to replace lost fluids and chemicals by intravenous infusion, to rule out any serious underlying disorder, and to control the vomiting.... vomiting in pregnancy
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