Birthweight: The first weight of a liveborn or stillborn baby obtained after birth.
Birthweight adjusted for gestational age: A baby may be small due to being pre-term (born early), or due to being small for gestational age (either due to genetic factors, or because it is the subject of a growth restriction within the uterus). Adjusting birthweight for gestational age allows for differences in a baby’s growth status and maturity to be taken into account when examining their health outcomes at birth. Data on birthweight adjusted for gestational age are limited to liveborn singleton babies. Babies are defined as being small for gestational age if their birthweight is below the 10th percentile for their gestational age and sex, as determined by national percentiles. Babies are defined as being large for gestational age if their birthweight is above the 90th percentile for their gestational age and sex.
Congenital anomaly: An atypical bodily structure or function that exists at or before birth, although it may not be detected until later in life. It may have significant medical, social or cosmetic outcomes for an individual and typically requires medical intervention. See Table 4 for brief descriptions of the anomalies included in this report.
Fetal death (stillbirth): Death prior to 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. The 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.
Gestational age: 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.
Infant death: Death of a liveborn child under 1 year of age.
Live birth: A live birth is defined by the World Health Organization to be the complete expulsion or extraction from the mother of a baby, 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 the 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. The NPDC has birthweight and gestational age conditions for those included in the collection as a ‘live birth’ or ‘stillbirth’. The very small number of live births occurring before 20 weeks’ gestation and weighing less than 400 grams are not included in the NPDC. Data for babies whose gestational age and birthweight were not recorded are also not included. Live births and stillbirths may include termination of pregnancy after 20 weeks. Terminations of pregnancy performed at 20 or more weeks of gestation may be included and recorded either as stillbirths or, in the event of showing evidence of life, as live births. There are variations in legislation regarding termination of pregnancy between states and territories, and recording of terminations is likely to be incomplete.
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.
Minor congenital anomalies: These are congenital anomalies that do not pose significant health issues to the baby and have limited social or cosmetic consequences. These types of anomalies were excluded from NCADC reporting.
Neonatal death: Death of a liveborn baby within 28 days of birth.
Parity: Number of previous pregnancies resulting in live births or fetal deaths, excluding the current pregnancy. In this report, categories include ‘primiparous’ for the first pregnancy, or ‘multiparous’, for one or more previous pregnancies.
Perinatal death: A fetal or neonatal death of at least 20 weeks’ gestation or at least 400 grams birthweight.
Plurality: The number of births resulting from a pregnancy. In this report, categories include ‘singleton’ for single births, and ‘multiple’ for the births of twins, triplets, quadruplets, quintuplets, sextuplets and other.
Post-neonatal death: Death of a liveborn baby more than 28 days after birth and less than one year after birth.
Post-term birth: Birth at 42 or more completed weeks of gestation.
Pre-term birth: Birth before 37 completed weeks of gestation.
Stillbirth: A fetal death prior to 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.
Termination of pregnancy: The intentional expulsion of a product of conception from the uterus either by medication or instrumentation, with the intention being the death of the embryo or fetus. This includes induction of labour without expectation of fetal survival, for example, in the case of severe pre-eclampsia at pre-viable gestations or prolonged rupture of membranes with severe infection.