Product of conception—gestational age, completed weeks N[N]

Identifying and definitional attributes
Metadata item type:	Data Element
Short name:	Gestational age
METEOR identifier:	298105
Registration status:	Health, Superseded 02/08/2017 Tasmanian Health, Superseded 03/07/2020
Definition:	The age of a product of conception in completed weeks.
Data Element Concept:	Product of conception—gestational age
Value Domain:	Total weeks N[N]

Value domain attributes
Representational attributes
Representation class:	Total
Data type:	Number
Format:	N[N]
Maximum character length:	2
	Value	Meaning
Supplementary values:	99	Not stated/unknown
Unit of measure:	Completed weeks

Data element attributes
Collection and usage attributes
Guide for use:	Gestational age is the best clinical estimate of the duration of pregnancy at a specific point in time, based on the first day of the last menstrual period, ultrasound or physical examination of the baby. Gestational age is conventionally expressed in completed weeks. When gestational age is calculated using the first day of the last normal menstrual period, the first day is counted as day zero and not day one. Therefore, a 25 week, 5 day fetus is considered a 25 week fetus (25+0, 25+1, 25+2, 25+3, 25+4, 25+5, 25+6). When ultrasound is used to date a pregnancy, the earliest ultrasound examination should be used and should preferably be between 6 and 10 weeks gestation. Scans performed beyond 24 weeks gestation are unlikely to be reliable in estimating gestational age and should not be used for this purpose. The duration of gestation can be determined from the first day of the last normal menstrual period, from ultrasound or clinical assessment. For the purpose of the national collection, gestational age is expressed in completed weeks. The World Health Organization identifies the following categories: pre-term: less than 37 completed weeks (less than 259 days) of gestation; term: from 37 completed weeks to less than 42 completed weeks (259 to 293 days) of gestation; and post-term: 42 completed weeks or more (294 days or more) of gestation.
Comments:	Gestational age is a key marker in pregnancy and an important risk factor for neonatal outcomes.
Source and reference attributes
Submitting organisation:	National Perinatal Data Development Committee
Origin:	International Classification of Diseases and Related Health Problems, 10 Revision, WHO, 1992
Reference documents:	American Academy of Pediatrics 2004. Policy statement Age terminology during the perinatal period. Paediatrics 114:5 November.
Relational attributes
Related metadata references:	Supersedes Female (pregnant)—estimated gestational age, total weeks NN Health, Superseded 02/12/2009 Has been superseded by Product of conception—gestational age, completed weeks N[N] Health, Superseded 12/12/2018 See also Pregnancy—estimated duration (at the first visit for antenatal care), completed weeks N[N] Health, Superseded 02/08/2017 Indigenous, Superseded 22/10/2018 Tasmanian Health, Superseded 03/07/2020 See also Pregnancy—estimated duration, total weeks N[N] WA Health, Standard 04/03/2014
Implementation in Data Set Specifications: All attributes +	Perinatal NMDS 2010-2011 Health, Superseded 21/12/2010 DSS specific attributes + Implementation start date: 01/07/2010 Implementation end date: 30/06/2011 DSS specific information: The first day of the last menstrual period (LMP) is required to estimate gestational age, which is a key outcome of pregnancy and an important risk factor for neonatal outcomes. Although the date of the LMP may not be known, or may sometimes be erroneous, estimation of gestational age based on clinical assessment may also be inaccurate. Both methods of assessing gestational age are required for analysis of outcomes. This item is collected for the mother only. Perinatal NMDS 2011-12 Health, Superseded 07/03/2012 DSS specific attributes + Implementation start date: 01/07/2011 Implementation end date: 30/06/2012 DSS specific information: The first day of the last menstrual period (LMP) is required to estimate gestational age, which is a key outcome of pregnancy and an important risk factor for neonatal outcomes. Although the date of the LMP may not be known, or may sometimes be erroneous, estimation of gestational age based on clinical assessment may also be inaccurate. Both methods of assessing gestational age are required for analysis of outcomes. This item is collected for the mother only. Perinatal NMDS 2012-13 Health, Superseded 07/02/2013 DSS specific attributes + Implementation start date: 01/07/2012 Implementation end date: 30/06/2013 DSS specific information: The first day of the last menstrual period (LMP) is required to estimate gestational age, which is a key outcome of pregnancy and an important risk factor for neonatal outcomes. Although the date of the LMP may not be known, or may sometimes be erroneous, estimation of gestational age based on clinical assessment may also be inaccurate. Both methods of assessing gestational age are required for analysis of outcomes. This item is collected for the mother only. Perinatal NMDS 2013-14 Health, Superseded 07/03/2014 DSS specific attributes + Implementation start date: 01/07/2013 Implementation end date: 30/06/2014 DSS specific information: The first day of the last menstrual period (LMP) is required to estimate gestational age, which is a key outcome of pregnancy and an important risk factor for neonatal outcomes. Although the date of the LMP may not be known, or may sometimes be erroneous, estimation of gestational age based on clinical assessment may also be inaccurate. Both methods of assessing gestational age are required for analysis of outcomes. This item is collected for the mother only. Perinatal NMDS 2014-18 Health, Superseded 02/08/2017 DSS specific attributes + Implementation start date: 01/07/2014 Implementation end date: 30/06/2018 DSS specific information: The first day of the last menstrual period (LMP) is required to estimate gestational age, which is a key outcome of pregnancy and an important risk factor for neonatal outcomes. Although the date of the LMP may not be known, or may sometimes be erroneous, estimation of gestational age based on clinical assessment may also be inaccurate. Both methods of assessing gestational age are required for analysis of outcomes. This item is collected for the mother only. Tasmanian Perinatal Data Set - 2016 Tasmanian Health, Standard 30/01/2017 DSS specific attributes + Implementation start date: 01/07/2016 Implementation end date: 30/06/2017 Tasmanian Perinatal Data Set - 2019 Tasmanian Health, Superseded 23/06/2020 DSS specific attributes + Implementation start date: 01/07/2019 Implementation end date: 30/06/2020
Implementation in Indicators:	Used as Numerator Australian Atlas of Healthcare Variation: Caesarean section for selected women giving birth for the first time, 2012-2014 Australian Commission on Safety and Quality in Health Care, Standard 07/06/2017 Australian Health Performance Framework: PI 3.1.6–Proportion of babies born with low birthweight, 2019 Health, Superseded 01/12/2020 National Core Maternity Indicators: PI 04-Apgar score of less than 7 at 5 minutes for births at or after term (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 04—Apgar score of less than 7 at 5 minutes for births at or after term (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 05-Induction of labour for selected women giving birth for the first time (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 05—Induction of labour for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 06-Caesarean section for selected women giving birth for the first time (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 06—Caesarean section for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 07-Normal (non-instrumental) vaginal birth for selected women giving birth for the first time (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 07—Normal (non-instrumental) vaginal birth for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 08-Instrumental vaginal birth for selected women giving birth for the first time (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 08—Instrumental vaginal birth for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 10-Small babies among births at or after 40 weeks gestation (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 10—Small babies among births at or after 40 weeks gestation (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2020 Health, Superseded 17/12/2021 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2017 Health, Superseded 30/01/2018 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2018 Health, Superseded 19/06/2019 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2019 Health, Superseded 13/03/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2020 Health, Standard 13/03/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2021 Health, Standard 16/09/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2022 Health, Standard 24/09/2021 National Indigenous Reform Agreement: PI 09—Antenatal care, 2016 Indigenous, Superseded 01/07/2016 National Indigenous Reform Agreement: PI 09—Antenatal care, 2017 Indigenous, Superseded 06/06/2017 National Indigenous Reform Agreement: PI 09-Antenatal care, 2018 Indigenous, Superseded 31/07/2018 National Indigenous Reform Agreement: PI 09-Antenatal care, 2019 Indigenous, Superseded 23/08/2019 National Indigenous Reform Agreement: PI 09-Antenatal care, 2020 Indigenous, Standard 23/08/2019 Used as Denominator Australian Health Performance Framework: PI 3.1.6–Proportion of babies born with low birthweight, 2019 Health, Superseded 01/12/2020 Caesarean section at less than 37, 38 and 39 completed weeks gestation without medical or obstetric indication, 2017 Australian Commission on Safety and Quality in Health Care, Standard 27/04/2021 Caesarean section or induction of labour at less than 37, 38 and 39 completed weeks gestation without medical or obstetric indication, 2017 Australian Commission on Safety and Quality in Health Care, Standard 27/04/2021 Early planned caesarean section without medical or obstetric indication, 2015 Australian Commission on Safety and Quality in Health Care, Standard 13/12/2018 National Core Maternity Indicators: PI 04-Apgar score of less than 7 at 5 minutes for births at or after term (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 04—Apgar score of less than 7 at 5 minutes for births at or after term (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 04–Apgar score of less than 7 at 5 minutes for births at or after term, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 05–Induction of labour for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 05-Induction of labour for selected women giving birth for the first time (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 05—Induction of labour for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 06–Caesarean section for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 06—Caesarean section for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 07–Non-instrumental vaginal birth for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 07—Normal (non-instrumental) vaginal birth for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 08–Instrumental vaginal birth for selected females giving birth for the first time, 2020 Health, Superseded 17/12/2021 National Core Maternity Indicators: PI 08—Instrumental vaginal birth for selected women giving birth for the first time (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 10-Small babies among births at or after 40 weeks gestation (2013) Health, Superseded 02/02/2016 National Core Maternity Indicators: PI 10—Small babies among births at or after 40 weeks gestation (2016) Health, Superseded 06/09/2018 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2018 Health, Superseded 19/06/2019 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2019 Health, Superseded 16/09/2020 National Core Maternity Indicators: PI 10–Small babies among births at or after 40 weeks gestation, 2020 Health, Superseded 17/12/2021 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2017 Health, Superseded 30/01/2018 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2018 Health, Superseded 19/06/2019 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2019 Health, Superseded 13/03/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2020 Health, Standard 13/03/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2021 Health, Standard 16/09/2020 National Healthcare Agreement: PI 01–Proportion of babies born of low birth weight, 2022 Health, Standard 24/09/2021 National Indigenous Reform Agreement: PI 07—Proportion of babies born of low birthweight, 2017 Indigenous, Superseded 06/06/2017 National Indigenous Reform Agreement: PI 07-Proportion of babies born of low birthweight, 2018 Indigenous, Superseded 31/07/2018 National Indigenous Reform Agreement: PI 07-Proportion of babies born of low birthweight, 2019 Indigenous, Superseded 23/08/2019 National Indigenous Reform Agreement: PI 07-Proportion of babies born of low birthweight, 2020 Indigenous, Standard 23/08/2019 National Indigenous Reform Agreement: PI 09—Antenatal care, 2016 Indigenous, Superseded 01/07/2016 National Indigenous Reform Agreement: PI 09—Antenatal care, 2017 Indigenous, Superseded 06/06/2017 National Indigenous Reform Agreement: PI 09-Antenatal care, 2018 Indigenous, Superseded 31/07/2018 National Indigenous Reform Agreement: PI 09-Antenatal care, 2019 Indigenous, Superseded 23/08/2019 National Indigenous Reform Agreement: PI 09-Antenatal care, 2020 Indigenous, Standard 23/08/2019