Infant Mortality Rate (imr): From 1 Different Sources
The number of deaths of infants under one year of age. The IMR in any given year is calculated as the number of deaths in the ?rst year of life in proportion to every 1,000 registered live births in that year. Along with PERINATAL MORTALITY, it is accepted as one of the most important criteria for assessing the health of the community and the standard of the social conditions of a country.
The improvement in the infant mortality rate has occurred mainly in the period from the second month of life. There has been much less improvement in the neonatal mortality rate – that is, the number of infants dying during the ?rst four weeks of life, expressed as a proportion of every 1,000 live births. During the ?rst week of life the main causes of death are asphyxia, prematurity, birth injuries and congenital abnormalities. After the ?rst week the main cause of death is infection.
Social conditions also play an important role in infant mortality. In England and Wales the infant mortality rate in 1930–32 was: Social Class I (professional), 32·7; Social Class III (skilled workers), 57·6; Social Class V (unskilled workers), 77·1. Many factors come into play in producing these social variations, but overcrowding is undoubtedly one of the most important.
1838–9 146 1950–52 30 1851–60 154 1960–62 22 1900–02 142 1970–72 18 1910–12 110 1980–82 12 1920–22 82 1990–92 7 1930–32 67 1996 6·2 1940–42 59 1999 5.8 2000 5.6
It is thus evident that for a reduction of the infant mortality rate to the minimum ?gure, the following conditions must be met. Mothers and potential mothers must be housed adequately in healthy surroundings, particularly with regard to safe water supplies and sewage disposal. The pregnant and nursing mother must be ensured an adequate diet. E?ective antenatal supervision must be available to every mother, as well as skilled supervision during labour (see PREGNANCY AND LABOUR). The newborn infant must be adequately nursed and fed and mothers encouraged to breast feed. Environmental and public-health measures must be taken to ensure adequate housing, a clean milk supply and full availability of medical care including such protective measures as IMMUNISATION against diphtheria, measles, poliomyelitis and whooping-cough. (See also PERINATAL MORTALITY.)
Death. Used to describe the relation of deaths to the population in which they occur.... mortality
In 2003, 695,500 live births were registered in the United Kingdom; 38 per cent occurred outside marriage. Overall, total fertility is falling slowly. The number of births per 1,000 women aged over 40 years has been rising, and in 1999 was 8.9 per cent. In Great Britain in 2003, 193,817 legal abortions were performed under the Abortion Act 1967.... birth rate
The proportion of deaths in a specified population. The death rate is calculated by dividing the number of deaths in a population in a year by the midyear resident population. Death rates are often expressed as the number of deaths per 100 000 persons. The rate may be restricted to deaths in specific age, race, sex, or geographic groups or deaths from specific causes of death (specific rate), or it may be related to the entire population (crude rate).... death rate
See “death rate”.... mortality rate
The number of fatal cases of specific disease, divided by total number of known cases and it is usually expressed as percent. Case fatality is one index of disease severity and is of more interest in acute than in chronic disease.... case fatality rate
See ESR.... erythrocyte sedimentation rate
The number of live births that occur in a year for every 1,000 women of childbearing age (this is usually taken as 15–44 years of age). The fertility rate in the UK (all ages) was 54.9 in 2002 (UK Health Statistics, 2001 edition, The Stationery O?ce).... fertility rate
A quotient, with the number of cases of a specified disease diagnosed or reported during a stated period of time as the numerator, and the number of persons in the population in which they occurred as the denominator.... incidence rate
A baby who is under one year old.... infant
A measure of the frequency of a phenomenon. In epidemiology, demography and vital statistics, a rate is an expression of the frequency with which an event occurs in a defined population. Rates are usually expressed using a standard denominator such as 1000 or 100 000 persons. Rates may also be expressed as percentages. The use of rates rather than raw numbers is essential for comparison of experience between populations at different times or in different places, or among different classes of persons.... rate
See ESR.... sedimentation rate
Each of the two KIDNEYS ?lters a large volume of blood – 25 per cent of cardiac output, or around 1,300 ml – through its two million glomeruli (see GLOMERULUS) every minute. The glomeruli ?lter out cell, protein, and fat-free ?uid which, after reabsorption of certain chemicals, is excreted as urine. The rate of this ultra?ltration process, which in health is remarkably constant, is called the glomerular ?ltration rate (GFR). Each day nearly 180 litres of water plus some small molecular-weight constituents of blood are ?ltrated. The GFR is thus an indicator of kidney function. The most widely used measurement is CREATININE clearance and this is assessed by measuring the amount of creatinine in a 24-hour sample of urine and the amount of creatinine in the plasma; a formula is applied that gives the GFR.... glomerular filtration rate (gfr)
quotient using as the numerator, the number of persons sick or portraying a certain condition, in a stated population, at a particular time, regardless of when that illness or condition began, and as the denominator, the number of persons in the population in which they occurred.... prevalence rate
A measure of the relative contribution to total mortality by a specific cause and these are expressed as number of deaths assigned to the state cause in a calendar year per 1000 total deaths in that year.... proportional mortality rate (pmr)
The newborn infant may be fed naturally from the breast, or arti?cially from a bottle.
Breast feeding Unless there is a genuine contraindication, every baby should be breast fed. The nutritional components of human milk are in the ideal proportions to promote the healthy growth of the human newborn. The mother’s milk, especially colostrum (the ?uid secreted before full lactation is established) contains immune cells and antibodies that increase the baby’s resistance to infection. From the mother’s point of view, breast feeding helps the womb to return to its normal size and helps her to lose excess body fat gained during pregnancy. Most importantly, breast feeding promotes intimate contact between mother and baby. A ?nal point to be borne in mind, however, is that drugs taken by a mother can be excreted in her milk. These include antibiotics, sedatives, tranquillisers, alcohol, nicotine and high-dose steroids or vitamins. Fortunately this is rarely a cause of trouble. (See also main entry on BREAST FEEDING.)
Arti?cial feeding Unmodi?ed cows’ milk is not a satisfactory food for the human newborn and may cause dangerous metabolic imbalance. If breast feeding is not feasible, one of the many commerciallly available formula milks should be used. Most of these are made from cows’ milk which has been modi?ed to re?ect the composition of human milk as closely as possible. For the rare infant who develops cows’-milk-protein intolerance, a milk based on soya-bean protein is indicated.
Feeding and weight gain The main guide as to whether an infant is being adequately fed is the weight. During the ?rst days of life a healthy infant loses weight, but should by the end of the second week return to birth weight. From then on, weight gain should be approximately 6oz. (170g) each week.
The timing of feeds reffects social convention rather than natural feeding patterns. Among the most primitive hunter-gatherer tribes of South America, babies are carried next to the breast and allowed to suckle at will. Fortunately for developed society, however, babies can be conditioned to intermittent feedings.
As the timing of breast feeding is ?exible – little or no preparation time being required – mothers can choose to feed their babies on demand. Far from spoiling the baby, demand feeding is likely to lead to a contented infant, the only necessary caution being that a crying baby is not always a hungry baby.
In general, a newborn will require feeding every two to four hours and, if well, is unlikely to sleep for more than six hours. After the ?rst months, a few lucky parents will ?nd their infant sleeping through the night.
Weaning Weaning on to solid foods is again a matter of individuality. Most babies will become dissatis?ed with a milk-only diet at around six months and develop enthusiasm for cereal-based weaning foods. Also at about this time they enjoy holding objects and transferring them to their mouths – the mouth being an important sense organ in infants. It is logical to include food items that they can hold, as this clearly brings the baby pleasure at this time. Introduction of solids before the age of four months is unusual and best avoided. The usual reason given for early weaning is that the baby appears hungry, but this is unlikely to be the case; crying due to COLIC, for example, is more probable. Some mothers take the baby’s desire to suck – say, on their ?nger – as a sign of hunger when this is, in fact, re?ex activity.
Delaying the start of weaning beyond nine months is nutritionally undesirable. As weaning progresses, the infant’s diet requires less milk. Once established on a varied solid diet, breast and formula milks can be safely replaced with cows’ milk. There is, however, no nutritional contraindication to continued breast feeding until the mother wishes to stop.
It is during weaning that infants realise they can arouse extreme maternal anxiety by refusing to eat. This can lead to force-feeding and battles of will which may culminate in a breakdown of the mother-child relationship. To avoid this, parents must resist the temptation to coax the child to eat. If the child refuses solid food, the meal should be taken away with a minimum of fuss. Children’s appetites re?ect their individual genetic structure and a well child will eat enough to grow and maintain satisfactory weight gain. If a child is not eating properly, weight gain will be inadequate over a prolonged period and an underlying illness is the most likely cause. Indeed, failure to thrive is the paediatrician’s best clue to chronic illness.
Advice on feeding Many sources of con?icting advice are available to new parents. It is impossible to satisfy everyone, and ultimately it is the well-being of the mother and infant and the closeness of their relationship that matter. In general, mothers should be wary of rigid advice. An experienced midwife, health visitor or well-baby-clinic nursing sister are among the most reliable sources of information.
Protein Fat per Sugar Calories per cent cent per cent per cent
Human milk 1·1 4·2 7·0 70 Cows’ milk 3·5 3·9 4·6 66
Composition of human and cows’ milk... infant feeding
A measure of the use of facilities, most often inpatient health facility use, determined by dividing the number of patient days by the number of bed days (or places) available, on average, per unit of time, multiplied by 100.... occupancy rate
The proportion of female mosquitoes that have laid eggs at least once. Use for age-grading a mosquito population.... parous rate
Review by a government or private agency of a hospital’s or health service’s budget and financial data, performed for the purpose of determining if the rates are reasonable of the rates and evaluating proposed rate increases.... rate review
A method of paying health care providers in which the government establishes payment rates for all payers for various categories of health service.... rate setting
The proportion of a hospital’s patients (or a subset, such as those with asthma) who are readmitted to the hospital following discharge with the same diagnosis. It is used as a performance measure where a higher rate indicates lower quality of care.... readmission rate
The number of completed or returned survey instruments (questionnaires, interviews, etc) divided by the total number of persons who would have been surveyed if all had participated. Usually expressed as a percentage.... response rate
The proportion of female mosquitoes that have sporozoites in the salivary gland.... sporozoite rate
See sudden infant death syndrome (SIDS).... death, sudden infant
A description of a baby whose muscles lack normal tension or tone (see hypotonia in infants).... floppy infant
the number of people from a specified population with a specified disease or condition admitted to hospitals in a given geographical area over a specified time period.... admission rate
see occupational mortality.... comparative mortality figure
the total number of events (e.g. cases of lung cancer) expressed as a rate per 1000 population. When factors such as age structure or sex of populations can significantly affect the rates (as in *mortality or *morbidity rates) it is more meaningful to compare age/sex specific rates using one or more age groups of a designated sex (e.g. lung cancer in males aged 55–64 years). More complex calculations, which take account of the age and sex structure of a population as a whole, can produce *standardized rates and *standardized mortality ratios (SMR).... crude rate
(GFR) the rate at which substances are filtered from the blood of the glomeruli into the Bowman’s capsules of the *nephrons. It is calculated by measuring the *clearance of specific substances (e.g. creatinine) and is an index of renal function. See eGFR.... glomerular filtration rate
see case fatality rate.... hospital fatality rate
see intensity-modulated radiotherapy.... imrt
(IMR) the number of deaths of children under one year of age per 1000 live births in a given year. Included in the IMR are the neonatal mortality rate (calculated from deaths occurring in the first four weeks of life) and postneonatal mortality rate (from deaths occurring from four weeks). Neonatal deaths are further subdivided into early (first week) and late (second, third, and fourth weeks). In prosperous countries neonatal deaths account for about two-thirds of infant mortalities, the majority being in the first week (in the UK the major cause is prematurity and related problems). The IMR is usually regarded more as a measure of social affluence than a measure of the quality of antenatal and/or obstetric care; the latter is more truly reflected in the *perinatal mortality rate.... infant mortality rate
the number of deaths due to complications of pregnancy, childbirth, and the puerperium per 100,000 live births (see also stillbirth). In 1952 concern about maternal mortality resulted in Britain in the setting up of a triennial *confidential enquiry into every such death to identify any shortfall in resources or care. The first triennial report was published in 1985. Since 2014 reports have been produced annually by MBRRACE-UK (Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries Across the UK). Levels of *maternal deaths are currently low: a report published in 2017 (covering 2013–15) counted 202 obstetric-related deaths (8.76 per 100,000 live births). Thromboembolism was the commonest direct cause of death (30 deaths, 1.13 per 100,000 live births), while heart disease was the commonest indirect cause of death (54 deaths, 2.34 per 100,000 live births).... maternal mortality rate
see infant mortality rate.... neonatal mortality rate
(PEFR) the maximum rate at which a person can forcibly expel air from the lungs at any time, expressed usually in litres per minute (occasionally in litres per second). A low value can help diagnose asthma in the correct clinical context, and differences between the morning and evening values can also be a feature of poor control of asthma. There is a place for PEFR in the monitoring of acute exacerbations of chronic pulmonary obstructive disease (COPD) but not in the diagnosis of COPD.... peak expiratory flow rate
(PNM) the total number of babies born dead after 24 weeks gestation (*stillbirths) and of live-born babies that die in the first week of life, regardless of gestational age at birth (early neonatal deaths), per 1000 live births and stillbirths. See infant mortality rate. See also confidential enquiries.... perinatal mortality rate
see fertility rate.... reproduction rate
(RR) breathing rate: the number of breaths per minute. Normally between 6 and 12, it increases after exercise and in cases of *respiratory distress and decreases after head injury and opioid overdosage.... respiratory rate
(SMR) the ratio of observed mortality rate to expected mortality rate (calculated using indirect standardization), expressed as an integer where 100 represents agreement between observed and expected rates. See standardized rates.... standardized mortality ratio
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