This scoping review found scarce and predominantly small-scale studies assessing the impact of maternal mental health problems on perinatal and childhood outcomes among Indigenous populations, although it is established that mental health issues disproportionately affect ethnic minorities and marginalised individuals. Although the evidence mainly came from studies that used the same population databases (5 of 7), maternal substance abuse disorder appears linked with poor infant/child outcomes, with similar associations for perinatal and childhood outcomes. However, the associations with the other common mental health problems remain under-investigated and therefore conclusions cannot be made.
Poor mental health is a common issue among the Indigenous population in general [38, 39], is typically intergenerational in nature and likely to involve complex layers of determinants [24]. Indigenous women are also at greater risk of perinatal mental health problems, including depression and anxiety, compared with non-Indigenous women [9, 40]. Despite this, surprisingly, we found only three studies that examined the link between maternal depression and anxiety and perinatal (preterm birth, birth weight) and infant behavioural outcomes, with mixed findings [27, 29, 31]. Two of the studies that reported null findings for the associations between maternal depression and anxiety, and perinatal outcomes, had limited statistical power. The other study found negative associations between maternal depression and child internalising and externalising behaviours, consistent with the evidence for the mainstream population [41].
Given the higher burden of mental health problems in Indigenous women and the common findings in the broader literature of a negative association between maternal mental health problems and a range of child outcomes [42, 43], there is a clear and critical need to establish an evidence base on the topic for the Australian Indigenous population. Such evidence will assist the development of targeted interventions that support a disruption of the intergenerational perpetuation of mental health disorders. Future epidemiological studies are also required to investigate whether maternal mental health problems have a differential effect on child outcomes for Indigenous and non-Indigenous populations. Such quantitative empirical studies should ideally recruit community-based representative samples and employ locally validated and reliable mental health assessment tools. These tools, especially when developed by or in consultation with Indigenous peoples and communities, will more likely reflect the concept of mental health (and broader construct of social and emotional wellbeing) within the holistic notion of Indigenous wellbeing than standard measurement tools [44–46]. For instance, based on recent systematic reviews [44, 47], the Edinburgh Postnatal Depression Scale (the most commonly used screening tool) was found rarely validated for use with Indigenous women, particularly for Australian Indigenous women. So, it may not be suitable for identifying mental health problems among Indigenous mothers. Thus, to estimate the actual burden and impact of mental health problems in this population, particularly in women of reproductive age, the development (or adaptation of standard measures) and utilization of culturally appropriate measurement tools are warranted.
Consistent with the overwhelming evidence in the general population, this review revealed that maternal substance abuse is associated with poor perinatal and child outcomes. Although the specific mechanism for the observed association between perinatal maternal substance use disorders and child negative physical and mental health outcomes is not fully understood, there are numerous plausible explanations. One suggested mechanism, particularly for adverse mental and behavioural outcomes in children is that maternal smoking and alcohol use during pregnancy can cross the placenta and significantly impact the developing brain and lead to poorer neurodevelopmental trajectories later in life [48]. In addition, epigenetic mechanisms are implicated in recent studies to indicate that maternal substance use during pregnancy can adversely affect children’s brain development and increase the risk of developing a wide range of mental and behaviours problems [49]. Maternal substance use during pregnancy can cause DNA methylation and histone modifications without altering the DNA sequence [50, 49, 51]. Maternal substance use disorders are also often linked with separations/divorce and undesirable changes in family functioning such as negative parent-child interactions [52, 53], which impact the normal brain development of children and increase the risk of mental and behavioural problems in later life [53–56].
Limitations
To our knowledge, this is the first scoping review that systematically evaluated the impact of maternal perinatal mental health problems on perinatal and childhood outcomes among Indigenous populations. We included any study type without time restriction. However, some relevant studies could have been excluded as our electronic search results were restricted to records published in the English language. Due to the limited number of studies, we could not examine whether the impact of maternal mental health problems differs by severity and onset, which underscores the need for better designed prospective cohort studies to establish this important evidence base.