Gestational diabetes mellitus (GDM) is increasing along with obesity (Hunt and Schuller 2007) and type 2 diabetes mellitus (T2DM) (Sicree et al. 2009; Australian Institute of Health and Welfare 2010b), with Indigenousa populations particularly affected (Naqshbandi et al. 2008). GDM causes serious complications in pregnancy, birth (HAPO Study Cooperative Research Group 2008; Coustan et al. 2010) and the longer term (Dyck et al. 2010), for both women and their infants. Compared to non-Indigenous women, Indigenous women have a higher risk of GDM (Steinhart et al. 1997; Dyck 2005; Young et al. 2002), at a younger age (Yue et al. 1996; Benjamin et al. 1993), and there is a much higher rate of both diagnosed and undiagnosed T2DM in pregnancy (Australian Institute of Health and Welfare 2010b). Women diagnosed with GDM have a very high risk of developing T2DM postpartum, compared to women who do not have GDM (Kim 2002; Bentley-Lewis et al. 2008; Chodick et al. 2010; Bellamy et al. 2009; Heikes et al. 2008), and Indigenous women experience the highest risk (Yue et al. 1996; Kim 2002). The emergence of diabetic disorders among young child-bearing women represents an ominous ‘tipping point’ (Canadian Diabetes Association 2011) in the diabetes epidemic (Yue et al. 1996), as exposure to diabetes in-utero also significantly compounds the health risks for the next generation (Dyck et al. 2010; Osgood et al. 2011), and GDM becomes an additional driver for T2DM (Bhattarai 2009; Osgood et al. 2011). T2DM is a serious metabolic disorder, characterised by hyperglycaemia and, if left undetected and untreated, increases the risk of serious complications in subsequent pregnancies, including congenital abnormalities (Bower et al. 1992; Farrell et al. 2002), and can lead to heart disease, stroke, kidney failure, limb amputations and blindness (Australian Institute of Health and Welfare 2010a). T2DM is a major cause of death and disability among Aboriginal people (Australian Bureau of Statistics 2008) and directly contributes to health disparities in Australia (Australian Bureau of Statistics 2010).
GDM includes pre-existing diabetes that has not been diagnosed before pregnancy, or temporarily glucose intolerance expedited by growth hormones in pregnancy (American Diabetes Association 2009). The increased insulin demands of pregnancy can ‘unmask’ (Lee et al. 2007) abnormalities in beta-cell function (Brown and Trost 2003; Moran et al. 2010), forewarning of the risk of progression to T2DM (Bilhartz et al. 2011). Most importantly, it offers a unique ‘window of opportunity’ for public health strategies because young women with no other identified conditions usually have frequent scheduled contacts with health-care providers for pregnancy care, often for the first time since early childhood. Pregnant women are also often highly motivated to adapt their lifestyles to improve the health of their infant (Kalra et al. 2011), with any effective support potentially benefitting the whole family (McBride et al. 2003; Orleans et al. 2000). The postpartum period also offers unique opportunities for women to reduce their risk (Schwarz et al. 2010; Liu et al. 2010) and the long-term risk for their infant (Owen et al. 2006; Pettitt et al. 1997), through breastfeeding.
Evidence about the risks of GDM (Coustan et al. 2010) has led to changes to international (International Association of Diabetes and Pregnancy Study Groups 2010) and national screening guidelines (Teh et al. 2011; Nankervis et al. 2013). The major changes include: offering screening in early pregnancy for women at high risk of T2DM, in addition to 24–28 weeks’ as is currently recommended; separating ‘probable’ undiagnosed T2DM from GDM; and changing the diagnostic thresholds for GDM. These changes are likely to significantly increase the prevalence of GDM in Australia (Round et al. 2010; Moses et al. 2011; Lindsay 2011; Morikawa et al. 2010; Leiberman et al. 2011; Flack et al. 2010; O’Sullivan et al. 2011), and have particular implications for Aboriginala women, who are categorised as having a high risk of T2DM (Chamberlain et al. 2011). While there are potential benefits, there are key criteria for introducing population-based screening, which specify that the benefits must outweigh the risks and inconvenience (Wilson and Jungner 1968), and that effective prevention, treatment and follow-up (postpartum) are provided (Australian Health Ministers’ Advisory Council 2008).
Despite the clear evidence of an increased risk of developing T2DM (Steinhart et al. 1997; Dyck et al. 2010; Young et al. 2002; McGrath et al. 2007), there are few studies investigating rates of postpartum T2DM screening for Aboriginal women with GDM (Chamberlain et al. 2013). Low rates of postpartum screening for T2DM have been reported for non-Indigenous women in Australia (Russell 2006; Morrison et al. 2009; Kim 2007; Sterne et al. 2011) and internationally (Pierce et al. 2011; Tovar et al. 2011; Keely et al. 2010), as well as Indigenous women in Canada (Shah et al. 2011; Mohamed and Dooley 1998), New Zealand (McGrath et al. 2007) and the United States (Steinhart et al. 1997). A review of postpartum diabetes screening reported rates ranging from 34% to 73%, with marked variations by race/ethnicity (Tovar et al. 2011b). One study reported low rates of postpartum screening for Aboriginal women in far north Queensland, however the region is confined to remote areas only and numbers were too small to assess trends (Davis et al. 2013). These low rates of postpartum T2DM screening are in stark contrast to high rates of postpartum screening for cervical cancer (Sterne et al. 2011), with one study reporting only 37% of eligible women underwent a postpartum Oral Glucose Tolerance Test (OGTT), while 94% underwent a postpartum papanicolaou test (Smirnakis 2005), which is also perceived as an unpleasant test for many women.
Some of the factors reported as barriers to postpartum screening include; lack of awareness of the need to attend screening, the inconvenience of the OGTT (which requires fasting, consuming a glucose drink, and a number of blood tests over several hours), and the need to attend with small children (Sterne et al. 2011; Bell et al. 2011; Clark and Keely 2012). However, there are likely to be additional barriers for women living in rural and remote areas (Eades et al. 2010). Rural and remote communities face challenges accessing health services due to the rugged and sometimes inaccessible terrain, and they may be required to travel long distances to access specialist services, including an OGTT. However, local services are not likely to incur fees, and individuals are more likely to be personally known to service providers in small communities. Most Aboriginal people now reside in urban areas, where there is comparatively limited research, particularly ‘intervention research’ (Eades et al. 2010), and different barriers which are not well understood (Eades et al. 2010). There may be limited publicly funded health services in regional urban areas, and private services may incur substantial fees. While there may be administrative arrangements to cover costs for health care card holders and/or Aboriginal women, these arrangements may not be well understood by women or healthcare providers in urban areas. While research suggests relatively simple strategies can increase postpartum diabetes screening (Carson et al. 2013), such as: structured systems (Mohamed and Dooley 1998), proactive postpartum care plans (Gabbe et al. 2011), antenatal education (Stasenko et al. 2011), physician reminders (Lega et al. 2011), patient reminders (Korpi-Hyovalti et al. 2012) and registers (Dannenbaum et al. 1999), local circumstances will need to be considered.
Effective lifestyle and breastfeeding support has been shown to reduce the risk of T2DM for non-Indigenous women and their children during (Landon et al. 2009; Crowther et al. 2005) and after pregnancy (Knowler 2002; Tuomilehto 2001; Pan 1997; O’Reilly et al. 2011; van der Pligt et al. 2013). There are no studies reporting effective diet and exercise support for Aboriginal women with GDM (Dyck et al. 1998; Gray-Donald et al. 2000; Klomp et al. 2003; Chamberlain et al. 2013), and studies report a lower sense of self-efficacy about postpartum weight loss among women categorised as ‘low socioeconomic status’ (SES). Breastfeeding support has also been shown to be effective (Karanja et al. 2010) and feasible (Murphy and Wilson 2008) among Indigenous women in the United States (US) and Canada, however no studies have been reported in Australia, despite one study suggesting breastfeeding rates may be lower among Aboriginal women with GDM than those without (Simmons et al. 2005). This is not surprising given women with GDM and their infants are more likely to experience complications which may inhibit breastfeeding (e.g. caesarean section, neonatal hypoglycaemia), and evidence these complications are more likely to have a differential impact on women categorised as ‘low SES’ , as they are more likely to have lower self-confidence and sense of self-efficacy about their ability to breastfeed (Demirtas 2012). While broader strategies addressing environmental determinants have been suggested (O’Dea et al. 2007; Stephenson 1993; Young et al. 2002), no such strategies have yet been reported (Chamberlain et al. 2013). The paucity of good quality ‘intervention research’ to prevent T2DM among Indigenous peoples has similarly been reported (McNamara et al. 2011), highlighting a gap in diabetes research more generally.
Adequate support for women diagnosed with GDM is also important for psychological wellbeing. The diagnosis of any medical condition can be associated with increased psychological stress (Sable and Wilkinson 2000), particularly during pregnancy as women are concerned about the health of their infant (Daniells et al. 2003; Rumbold and Crowther 2002; Langer and Langer 1994; Cosson 2010). While recent studies suggest that a GDM diagnosis may not increase stress among non-Aboriginal women in Australia (Coustan 2010; Rumbold and Crowther 2002), it has been reported among ethnic minority groups (Razee et al. 2010). Furthermore, studies among Indigenous women in the US and Canada, report increased stress (Neufeld 2011) and ‘risk perception’, coupled with low perceptions of ‘self-efficacy’ associated with a GDM diagnosis, despite high levels of knowledge (Jones et al. 2012). Aboriginal women may be more likely to experience additional stressors. For example, they are more likely to live in geographically remote areas and may be required to travel to a major urban city for specialist care and be thousands of miles from family, and they are more likely to know people experiencing serious consequences of T2DM. Effective interventions and postpartum care are critical to improving confidence and self-efficacy with regards to lifestyle and breastfeeding, reducing stress associated with a diagnosis of GDM, and providing appropriate treatment when needed to mitigate the risks to subsequent pregnancies and the long term risks for women.
Research aims and objectives
This paper describes the methods for a retrospective cohort study which aims to evaluate postpartum care for Aboriginal and non-Aboriginal women with GDM in urban, rural and remote regions in far north Queensland from 2004 to 2010. The purpose is to identify barriers and enablers to improve postpartum care for women with GDM, in all geographic regions. Trend analysis over time is also essential for evaluating whether improvements are occurring as changes have been introduced.
More specifically, the objectives are to:
report the proportion of women diagnosed with GDM who receive postpartum T2DM screening as per guidelines (OGTT at 6 weeks, annually and biannually thereafter) (Queensland Health and Royal Flying Doctors Service (Queensland Section) 2009);
report the rate of progression from GDM to T2DM;
investigate the recorded rates of other preventive activities, such as breastfeeding and visits to a dietician or diabetes educator during pregnancy; and
assess the degree to which confounders impact on rates of postpartum T2DM screening, progression to T2DM, breastfeeding, and dietician or diabetes educator consultations.