Maternal medical conditions
Diabetes and hypertension (high blood pressure) are significant sources of maternal illness and death. Pregnant women with pre-existing or gestational diabetes or pre-existing or gestational hypertension disorders have increased risk of developing adverse outcomes in pregnancy (AIHW 2023a).
Diabetes
Diabetes affecting pregnancy can be pre-existing (that is, type 1 or type 2) or may arise because of the pregnancy (gestational diabetes).
The type and severity of complications differs according to the type of diabetes experienced in pregnancy and can have both short-term and long-term implications (AIHW 2023a). For more information on diabetes in pregnancy, see Maternal medical conditions in Australia's mothers and babies.
International research suggests severe COVID-19 infection during pregnancy is related to an increased risk of gestational diabetes (Wei et al. 2021).
During March 2020, peak Australian diabetes organisations temporarily changed the recommended guidelines for the screening and diagnosis of gestational diabetes (AIHW 2023b), which may have led to underdiagnosed cases of gestational diabetes (Kevat 2023).
According to a preliminary study of pregnant women in Queensland, changes to guidelines were not associated with increased frequency of adverse perinatal outcomes, except for a potential increase in caesarean delivery (Meloncelli et al. 2023).
Figure 14 presents data on diabetes during pregnancy. Data exclude Victoria for data quality reasons. This may have an impact on the results in this section, as Victoria was significantly impacted by the COVID-19 pandemic relative to most Australian jurisdictions.
Figure 14: Proportion of women who gave birth, by maternal diabetes status and state and territory of birth, 2015 to 2021
Line graph shows maternal diabetes status by state and territory of birth between 2015 and 2021.
Between 2015 and 2019, the proportion of women who had gestational diabetes increased year-on-year (from 9.4% in 2015 to 13.5% in 2019), with further increases in 2020 (14.3%) and 2021 (15.2%). Between 2015 and 2021, the proportion of women who had pre-existing diabetes remained relatively stable between 1.0% and 1.2%.
It was not possible to undertake linear regression modelling for diabetes status due to high variability between years of data. For more information on modelling the trend over time, see Methods.
Hypertension
Hypertension (high blood pressure) affecting pregnancy can be pre-existing (that is, chronic) or may arise or worsen because of the pregnancy (gestational hypertension or pre-eclampsia).
Complications of hypertension can affect the short-term and long-term health of both mother and baby (AIHW 2023a; Queensland Health 2021). For more information on hypertension during pregnancy, see Maternal medical conditions in Australia's mothers and babies.
International research is currently mixed on whether COVID-19 infection during pregnancy is related to an increased risk of pre-eclampsia and gestational hypertension (Örtqvist et al. 2023; Smith et al. 2023; Wei et al. 2021).
Uncertainty remains around whether the increased uptake of telehealth services led to underdiagnosis of hypertensive conditions (Thirugnanasundralingam et al. 2023).
In Australia, there is some research to suggest that the COVID-19 pandemic restrictions might have been associated with higher rates of gestational hypertension (Rolnik et al. 2021), but less is known about pre-existing hypertension.
Figure 15 presents data on hypertension during pregnancy. Data exclude Victoria for data quality reasons. This may have an impact on the results in this section, as Victoria was significantly impacted by the COVID-19 pandemic relative to most Australian jurisdictions.
Figure 15: Proportion of women who gave birth, by maternal hypertension status and state and territory of birth, 2015 to 2021
Line graph shows maternal hypertension status by state and territory of birth between 2015 and 2021.
Between 2015 and 2019, the proportion of women who had gestational hypertension decreased from 3.7% in 2015 to 3.3% in 2019. Modelling showed that this was an annual decrease of 0.1 percentage points. The observed proportion of women who had gestational hypertension was 3.4% in 2020 and 3.2% in 2021, which was higher than the predicted proportions based on the modelling (3.2% in 2020 and 3.1% in 2021). This equated to around 880 more women with gestational hypertension during pregnancy than predicted in 2020 and 2021 combined.
For more information on modelling the trend over time, see Methods.
In 2020 and 2021, despite the slightly higher than expected proportion of mothers with gestational hypertension, there was no increase in the proportion of babies with adverse outcomes among mothers with gestational hypertension such as pre-term birth, low birthweight, Apgar score of less than 7 or admission to SCN or NICU, compared with previous years.
AIHW (Australian Institute of Health and Welfare) (2023a) Australia’s mothers and babies, AIHW, Australian Government.
AIHW (Australian Institute of Health and Welfare) (2023b) Diabetes: Australian facts, AIHW, Australian Government.
Kevat DAS (2023) ‘Diagnosing gestational diabetes during the COVID-19 pandemic: a glimpse into the future?’, Med J Aust, 219(10):462-463, doi:10.5694/mja2.52143.
Meloncelli NJL, Barnett AG, Cameron CM, McIntyre D, Callaway LK, d’Emden MC and de Jersey SJ (2023) ‘Gestational diabetes mellitus screening and diagnosis criteria before and during the COVID-19 pandemic: A retrospective pre-post study’, Med J Aust, doi:10.5694/mja2.52129.
Örtqvist AK Magnus MC, Dahlqvist E, Söderling J, Johansson K, Sandström A, Håberg SE and Stephansson O (2023) ‘Association between SARS-CoV-2 infection and newly diagnosed hypertension during pregnancy: prospective, population based cohort study’, BMJ, 2(1).
Queensland Health (2021) Hypertension and pregnancy, Queensland Health website.
Rolnik DL, Matheson A, Liu Y, Chu S, McGannon C, Mulc B, Malhotra A, Palmer KR, Hodges RJ and Mol BW (2021) ‘Impact of COVID-19 pandemic restrictions on pregnancy duration and outcome in Melbourne, Australia’, Ultrasound Obstet Gynecol, 58:677-687, doi:10.1001/uog.23753.
Smith ER, Oakley E, Grandner GW, Ferguson K, Farooq F, Afshar Y, Ahlberg M, Ahmadzia H, Akelo V, Aldrovandi G, Tippett Barr BA, Bevilacqua E, Brandt JS, Broutet N, Fernández Buhigas I, Carrillo J, Clifton R, Conry J, Cosmi E, Crispi F, Crovetto F, Delgado-López C, Divakar H, Driscoll AJ, Favre G, Flaherman VJ, Gale C, Gil MM, Gottlieb SL, Gratacós E, Hernandez O, Jones S, Kalafat E, Khagayi S, Knight M, Kotloff K, Lanzone A, Le Doare K, Lees C, Litman E, Lokken EM, Laurita Longo V, Madhi SA, Magee LA, Martinez-Portilla RJ, McClure EM, Metz TD, Miller ES, Money D, Moungmaithong S, Mullins E, Nachega JB, Nunes MC, Onyango D, Panchaud A, Poon LC, Raiten D, Regan L, Rukundo G, Sahota D, Sakowicz A, Sanin-Blair J, Söderling J, Stephansson O, Temmerman M, Thorson A, Tolosa JE, Townson J, Valencia-Prado M, Visentin S, von Dadelszen P, Adams Waldorf K, Whitehead C, Yassa M and Tielsch JM; (2023) ‘Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis’, BMJ Glob Health, 8(1):9495, doi:10.1136/bmjgh-2022-009495
Thirugnanasundralingam K, Davies-Tuck M, Rolnik DL, Reddy M, Mol BW, Hodges R, Palmer KR (2023) ‘Effect of telehealth-integrated antenatal care on pregnancy outcomes in Australia: an interrupted time-series analysis’, The Lancet: Digital Health, 5(11):798-811.
Wei SQ, Bilodeau-Bertrand M, Liu S and Auger N (2021) ‘The impact of COVID-19 on pregnancy outcomes: a systematic review and meta-analysis’, CMAJ, 193(16):540-548, doi:10.1503/cmaj.202604.