accommodation type: Accommodation chargeable status elected by a patient on admission to hospital i.e. public or private status.
admitted patient: A patient who undergoes a hospital’s admission process to receive treatment and/or care. This treatment and/or care is provided over a period of time and can occur in hospital and/or in the person’s home (for hospital-in-the-home patients).
age-specific rate: A rate for a specific age group. The numerator and denominator relate to the same age group.
age standardisation: A method of removing the influence of age when comparing populations with different age structures. This is usually necessary because the rates of many diseases vary strongly (usually increasing) with age. The age structures of the different populations are converted to the same ‘standard’ structure, and then the disease rates that would have occurred with that structure are calculated and compared.
age structure: The relative number of people in each age group in a population.
amniotic fluid embolism: A rare obstetric emergency in which it is postulated that amniotic fluid, fetal cells, hair or other debris enter the maternal circulation, causing cardiorespiratory collapse.
antenatal: The period covering conception up to the time of birth. Synonymous with prenatal.
antepartum fetal death: Fetal death occurring before the onset of labour.
antepartum haemorrhage: Bleeding from the uterus that occurs during pregnancy or early in labour but before birth.
Apgar score: Numerical score used to indicate the baby’s condition at 1 minute and at 5 minutes after birth. Between 0 and 2 points are given for each of 5 characteristics: heart rate, breathing, colour, muscle tone and reflex irritability. The total score is between 0 and 10.
augmentation of labour: Intervention after the spontaneous onset of labour to assist the progress of labour.
baby’s length of stay: Number of days between date of birth and date of separation from the hospital of birth (calculated by subtracting the date of birth from the date of separation).
birth: An event in which a baby comes out of the uterus after a pregnancy of at least 20 weeks gestation or weighing 400 grams or more.
birth status: Status of the baby immediately after birth (stillborn or liveborn).
birthweight: The first weight of the baby (stillborn or liveborn) obtained after birth (usually measured to the nearest 5 grams and obtained within 1 hour of birth).
breech presentation: A fetal presentation in which the buttocks are at the opening of the uterus. In a frank breech, the legs are straight up in front of the body. In a complete breech the legs are folded, but the feet are above the buttocks. In an incomplete breech, the feet are below the buttocks.
body mass index (BMI): The most commonly used method of assessing whether a person is normal weight, underweight, overweight or obese (see obesity). It is calculated by dividing the person’s weight (in kilograms) by their height (in metres) squared; that is, kg ÷ m2. For both men and women, underweight is a BMI below 18.5, acceptable weight is from 18.5 to less than 25, overweight is from 25 to less than 30, and obese is 30 and over. Sometimes overweight and obese are combined, and is defined as a BMI of 25 and over.
caesarean section: A method of birth in which a surgical incision is made into the mother’s uterus via the abdomen to directly remove the baby.
cardiovascular: The heart and/or major blood vessels.
chorioamnionitis: An inflammation, usually from infection, of the membranes surrounding the fetus.
coincidental maternal deaths: deaths from unrelated causes that happen to occur in pregnancy or the puerperium.
congenital: A condition that is recognised at birth, or that is believed to have been present since birth, including conditions that are inherited or caused by environmental factors.
congenital abnormality: A defect present at birth.
diabetes (diabetes mellitus): A chronic condition in which the body cannot properly use its main energy source, the sugar glucose. This is due to a relative or absolute deficiency in insulin. Insulin, a hormone produced by the pancreas, helps glucose enter the body’s cells from the bloodstream and then be processed by them. Diabetes is marked by an abnormal build-up of glucose in the blood and can have serious short- and long-term effects.
direct maternal deaths: deaths resulting from obstetric complications of the pregnant state (pregnancy, labour and puerperium) from interventions, omissions, incorrect treatment or from a chain of events resulting from any of the above.
duration of pregnancy: The duration of pregnancy in completed weeks calculated from the date of the first day of a woman’s last menstrual period and her baby’s date of birth, or via ultrasound, or derived from clinical assessment during pregnancy or from examination of the baby after birth.
early neonatal death: Death of a liveborn baby within 7 days of birth.
episiotomy: An incision of the perineum and vagina to enlarge the vulval orifice.
factor-specific rate of perinatal mortality: The perinatal mortality rate applied to subpopulations with different characteristics for a given factor. For example, the factor ‘maternal age’ can be used to calculate the perinatal mortality rate for different maternal age groups. For women aged 25–29, the numerator is the number of stillbirths for women aged 25–29 and the denominator is the number of total births for women aged 25–29.
Fetal alcohol spectrum disorder (FASD): A range of adverse physical, learning and behavioural effects on a child due to their being exposed to alcohol in the womb during their mother’s pregnancy.
fetal death (stillbirth): Death, before the complete expulsion or extraction from its mother, of a product of conception of 20 or more completed weeks of gestation or of 400 grams or more birthweight. Death is indicated by the fact that, after such separation, the fetus does not breathe or show any other evidence of life, such as beating of the heart, pulsation of the umbilical cord or definite movement of voluntary muscles.
fetal death rate: Number of fetal deaths per 1,000 total births (fetal deaths plus live births).
fetus papyraceous and fetus compressus: Products of conception recognisable as a deceased fetus.
first degree laceration: Graze, laceration, rupture or tear of the perineal skin during delivery that may be considered to be slight or that involves fourchette, labia, vagina or vulva.
first-time mother: See primipara.
first trimester: Before 14 weeks gestational age.
forceps: Handheld, hinged obstetric instrument applied to the fetal head to assist birth.
fourth degree laceration: Perineal laceration, rupture or tear, as in third degree laceration, occurring during delivery and also involving anal mucosa or rectal mucosa.
gestational age: Duration of pregnancy in completed weeks, calculated from the date of the first day of a woman’s last menstrual period and her baby’s date of birth; or via ultrasound; or derived from clinical assessment during pregnancy or from examination of the baby after birth.
gestational diabetes: A form of diabetes that is first diagnosed during pregnancy (gestation). It may disappear after pregnancy, but signals a high risk of diabetes occurring later on.
gestational hypertension: A form of hypertension that is first diagnosed during pregnancy (gestation).
haemorrhage (bleeding): The escape of blood from a ruptured blood vessel, externally or internally.
high blood pressure/hypertension: Definitions vary but a well-accepted one is from the World Health Organization (WHO): a systolic blood pressure of 140 mmHg or more or a diastolic blood pressure of 90 mmHg or more, or [the person is] receiving medication for high blood pressure.
hospital episode: Synonymous with admission and separation; that is, an episode of hospital care starts with the formal admission process and ends with the formal separation process. An episode of care can be completed by the patient being discharged or transferred to another hospital or care facility, by the patient dying, or by a portion of a hospital stay beginning or ending in a change of type of care (for example, from acute to rehabilitation).
hospital sector: Whether a patient was admitted to a public or a private hospital. In Western Australia, some private hospitals admit public women, hence the number of women who elect private accommodation type might be lower than the number of women admitted to private hospitals. Care must be taken when interpreting these numbers.
hospitalisation: See hospital episode.
ICD-10-AM: See International Statistical Classification of Diseases and Related Health Problems.
incidence: The number of new cases (of an illness, disease or event) occurring during a given period.
Indigenous: A person of Aboriginal and/or Torres Strait Islander descent who identifies as an Aboriginal and/or Torres Strait Islander.
indirect maternal deaths: deaths resulting from previous existing diseases or diseases that developed during pregnancy, and which were not due to a direct obstetric cause, but were aggravated by the physiologic effects of pregnancy.
induction of labour: Intervention to stimulate the onset of labour.
instrumental delivery: Vaginal delivery using forceps or vacuum extraction.
International Statistical Classification of Diseases and Related Health Problems: The World Health Organization’s internationally accepted classification of death and disease. The 10th Revision (ICD-10) is currently in use. The 10th revision, Australian Modification (ICD-10-AM) is currently in use in Australian hospitals for admitted patients.
intrapartum fetal death: Fetal death occurring during labour.
intrauterine growth restriction: A fetus whose estimated weight is below the 10th percentile for its gestational age.
labour: The physiological process by which a vaginal birth occurs that commences at the onset of regular uterine contractions that act to produce progressive cervical dilatation, and is distinct from spurious labour or pre-labour rupture of membranes.
late neonatal death: Death of a liveborn baby after 7 completed days and before 28 completed days.
live birth: The complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of the pregnancy, which, after such separation, breathes or shows any other evidence of life, such as beating of the heart, pulsation of the umbilical cord or definite movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached; each product of such a birth is considered liveborn (WHO definition).
low birthweight: Weight of a baby at birth that is less than 2,500 grams.
maternal age: Mother’s age in completed years at the birth of her baby.
maternal death: the death of a woman while pregnant or within 42 days of the end of pregnancy, irrespective of the duration of the pregnancy. Maternal deaths are divided into two categories, direct and indirect.
maternal deaths, not further classified: deaths considered to be related to the pregnancy or its management, but could not be further classified as either ‘direct’ or ‘indirect’.
maternal mortality ratio (MMR): the incidence of maternal death for a defined place and time, using direct and indirect deaths combined (excluding coincidental deaths), over the number of women who gave birth.
mode of separation: Status at separation of patient (discharge/transfer/death) and place to which patient is released (where applicable).
mother’s length of stay: Number of days between admission date (during the admission resulting in a birth) and separation date (from the hospital where birth occurred). The interval is calculated by subtracting the date of admission from the date of separation.
multipara: a pregnant woman who has had at least one previous pregnancy resulting in a live birth or stillbirth.
National Minimum Data Set (NMDS): A minimum set of data elements agreed for mandatory collection and reporting at a national level.
neonatal death: Death of a liveborn baby within 28 days of birth.
neonatal mortality rate: Number of neonatal deaths per 1,000 live births.
normal weight: Defined for population studies as a body mass index of 18.5–24.9.
non-Indigenous: People who have indicated that they are not of Aboriginal or Torres Strait Islander descent.
non-obstetric haemorrhage: Haemorrhage in pregnancy from blood vessels other than those in the genital tract; most commonly haemorrhage from a ruptured blood vessel in the brain or in the abdomen (the splenic artery).
obesity: Marked degree of overweight, defined for population studies as a body mass index of 30 or over.
obstetric haemorrhage: Haemorrhage from the female genital tract associated with pregnancy and birth.
other Australians: People who have declared they are not of Aboriginal or Torres Strait Islander descent, and those for whom their Indigenous status is unknown. Compare with Indigenous.
overweight: Defined for population studies as a body mass index of 25.0–29.9.
parity: Number of previous pregnancies resulting in live births or stillbirths, excluding the current pregnancy.
perinatal: Pertaining to or occurring in the period shortly before or after birth (usually up to 28 days after).
perinatal death: A fetal or neonatal death of at least 20 weeks gestation or at least 400 grams birthweight.
perinatal mortality rate: Number of perinatal deaths per 1,000 total births (fetal deaths plus live births).
perinatal mortality review committees (PMRCs): State and territory-based multidisciplinary committees that review perinatal deaths to ascertain the underlying and contributory cause/s of death.
perineal status: State of the perineum following birth. Perineal status is categorised as intact, first, second, third, or fourth degree laceration, episiotomy, or as another type of perineal laceration, rupture or tear.
Perineum: The area of skin between the vagina and the anus, and the underlying fibro-muscular perineal body which is an important part of the support structures of the uterus and vagina.
peripartum hysterectomy: A pregnancy-associated hysterectomy that occurs immediately after the birth of a baby (live birth or stillbirth) of at least 20 weeks’ gestation or weighing at least 400 grams at birth, or in the postpartum period, that is up to 6 weeks after birth. See also pregnancy-associated hysterectomy.
plurality: Number of births resulting from a pregnancy.
postneonatal death: Death of a liveborn baby after 28 days and within 1 year of birth.
postpartum haemorrhage: Primary postpartum haemorrhage is excessive bleeding from the genital tract after childbirth, occurring within 24 hours of birth. Secondary postpartum haemorrhage is excessive bleeding from the genital tract after childbirth, occurring between 24 hours and 6 weeks post-partum.
post-term birth: Birth at 42 or more completed weeks of gestation.
presentation at birth: The part of the fetus that presents first at birth.
pre-eclampsia: A multi-system disorder unique to human pregnancy characterised by hypertension and involvement of one or more other organ systems and/or the fetus. Proteinuria is the most commonly recognised additional feature after hypertension but should not be considered mandatory to make the clinical diagnosis.
pre-term birth: Birth before 37 completed weeks of gestation.
pregnancy-associated hysterectomy: The surgical removal of the uterus performed either:
- in pregnancy, for example in association with an abortion or termination of pregnancy, including in early pregnancy
- immediately after a woman has given birth, or
- in the postpartum period, up to 6 weeks after birth.
It is usually an emergency life-saving procedure to arrest massive obstetric haemorrhage. Hysterectomy may include removal of the cervix and ovaries, fallopian tubes and lymph nodes and lymph channels. The uterus may be removed through the abdominal wall or through the vagina and in some cases the procedure may be performed laparoscopically. Menstruation ceases after hysterectomy.
primary caesarean section: Caesarean section to a mother with no previous history of caesarean section.
primipara: Pregnant woman who has had no previous pregnancy resulting in a live birth or stillbirth.
principal diagnosis: The diagnosis established after study to be chiefly responsible for occasioning an episode of admitted patient care, an episode of residential care or an attendance at the health care establishment.
procedure: A clinical intervention that is surgical in nature, carries a procedural risk, carries an anaesthetic risk, requires specialised training and/or requires special facilities or equipment available only in an acute care setting.
puerperium: The time after childbirth, lasting approximately 6 weeks, during which the anatomical and physiological changes brought about by pregnancy resolve and a woman adjusts to the new or expanded responsibilities of motherhood and non-pregnancy life.
rate: A number (the numerator) divided by another number (the denominator). The numerator is commonly the number of events in a specified time. The denominator is the population ‘at risk’ of the event. Rates (crude, age-specific and age-standardised) are generally multiplied by a number such as 100,000 to create whole numbers.
resuscitation of baby: Active measures taken shortly after birth to assist the baby’s ventilation and heartbeat, or to treat depressed respiratory effort and to correct metabolic disturbances.
second degree laceration: Perineal laceration, rupture or tear, as in first degree laceration, occurring during delivery and also involving pelvic floor, perineal muscles or vaginal muscles.
separation: The term used to refer to the episode of admitted patient which can be a total hospital stay (from admission to discharge, transfer or death) or a portion of a hospital stay beginning or ending in a change of type of care (for example, from acute to rehabilitation). See also hospital episode.
special care nursery/neonatal intensive care unit (SCN/NICU): A facility dedicated to the care of neonates requiring care and sophisticated technological support.
spontaneous labour: Onset of labour without intervention.
spontaneous vaginal birth: Birth without intervention in which the baby’s head is the presenting part.
stillbirth: See fetal death (stillbirth).
teenage mother: Mother aged younger than 20 at the birth of her baby.
term birth: Birth at 37–41 completed weeks of gestation.
third degree laceration: Perineal laceration, rupture or tear, as in second degree laceration, occurring during delivery and also involving the anal floor, rectovaginal septum or sphincter not otherwise specified.
thromboembolism: Obstruction of a blood vessel (most frequently the pulmonary blood vessels) by a blood clot that has become dislodged from another site in the circulation.
total births: The combined number of live births and stillbirths.
unclassified death: maternal death from unspecified or undetermined cause occurring during pregnancy, labour and delivery, or the puerperium.
underweight: Defined for population studies as a body mass index less than 18.5.
vacuum extraction: Assisted birth using traction or rotation on a suction cap applied to the baby’s head.
Definitions for medical conditions
The following definitions are from Harris et al. 2011.
abnormal placentation: See placenta praevia, placental abruption, placenta accreta, placenta percreta and placenta increta.
antepartum haemorrhage: Bleeding from the uterus during a pregnancy in which the placenta appears to be normally situated, particularly after the 28th week and before the first stage of labour.
atony (as in ‘uterine atony’): Decreased or absent muscle tone.
intrapartum haemorrhage: Copious bleeding during labour, usually caused by abruption placentae or placenta praevia.
leoimyoma: A benign tumour of smooth muscle.
morbidly adherent placenta: See placenta accreta, placenta increta and placenta percreta.
placenta accreta: A placenta that invades the uterine muscle making separation from the muscle difficult. Note the term ‘placenta accreta’ is widely used to refer to all cases of placenta accreta/increta/percreta (unless specified).
placenta increta: A placenta that invades the uterine muscle and passes through the wall of the uterus into the abdominal cavity and adheres to adjacent abdominal organs, such as the bladder or bowel. See also placenta accreta.
placenta percreta: A placenta that invades the uterine muscle and passes through the wall of the uterus into the abdominal cavity. See also placenta accreta.
placenta praevia: A condition of pregnancy in which the placenta is implanted abnormally in the uterus so that it impinges on, or covers, the internal opening of the uterine cervix.
placental abruption (abruptio placentae): Separation of the placenta implanted in normal position in a pregnancy of 20 weeks or more or during labour before delivery of the fetus.
Harris P, Nagy S & Vardaxis N (eds) 2011. Mosby’s dictionary of medicine, nursing and health professions. 2nd Australian and New Zealand edition. Chatswood, NSW: Elsevier Australia.