First trimester is defined as within the first 13 weeks of pregnancy.
Births include both live births and stillbirths of at least 20 weeks gestation or 400 grams birth weight.
The percentages of women who gave birth and had at least one antenatal visit in the first trimester are calculated at Medicare Local catchment and Medicare Local peer group levels for:
- All women who gave birth during the two calendar years from 1 January 2010 to 31 December 2011
- Aboriginal and Torres Strait Islander women who gave birth during the two calendar years from 1 January 2010 to 31 December 2011.
Analysis by Medicare Local catchment and Medicare Local peer group is based on Statistical Local Area (SLA) of usual residence of the mother, irrespective of where the birth occurred.
Women who gave birth at any time during the two calendar years from 1 January 2010 to 31 December 2011 are included. Therefore, women who gave birth more than once during the two-year period are counted for each birth.
Women whose gestation at first antenatal visit was unknown or not stated are excluded.
Australian non-residents and residents of external territories are excluded.
State and territory differences in definitions and methods used for data collection affect the comparability of these data across state and territory jurisdictions and lower levels of geography within these jurisdictions. The following caveats apply to the data for 2010 and 2011:
In Western Australia, gestational age at the first antenatal visit is reported by birth hospital, therefore data may not be available for women who attend their first antenatal visit outside the birth hospital
In Tasmania, data on duration of pregnancy at the first antenatal visit was not reported by hospitals still using the paper-based form for collection of NPDC data, so these data should be interpreted with caution
In the Australian Capital Territory, the first hospital antenatal clinic visit is often reported as the first antenatal visit and, in many cases, earlier antenatal care provided by the woman’s GP is not reported.