Results endorse findings from other LAMI countries that the prevalence of depressed mood is higher in economically deprived populations than in rich contexts. Depressed mood was present for 39% of women in the present study, compared with 7.4% to 12.8% found in high income countries, depending on the trimester of pregnancy [32
]. It is also higher than the prevalence found in several other LAMI countries such as Nigeria, Pakistan and Brazil, where prevalence rates are 10.8% [33
], 25% [34
] and 20% [35
] respectively. The prevalence for postnatal depression in Cape Town peri-urban settlements is 34.7% [5
], suggesting that the prevalence of distress throughout the time surrounding childbirth is high.
The strongest predictors of depressed mood in pregnancy were lack of emotional support from women's partners, relationship violence, a household income below R2000 per month, and young age. The association between poor partner support and maternal depression is consistent with research from many countries both pre and postnatally [36
]. Similarly, research from several LAMI countries finds violence to be associated with depressed mood both in pregnancy [35
], and in the postnatal period [8
]. In South Africa, this association is concerning because domestic violence against women is highly prevalent [41
], and especially so in populations where poverty is endemic [42
The association between household income and depressed mood is evidence of a relationship between economic deprivation and depression. Although no longer significant after controlling for other variables, being unemployed, being poorly educated and receiving no financial support from the baby's father were also associated with depressed mood in the bivariate analysis. Housing type as formal or informal and household services, however, were not. It might be that because economic disadvantage was endemic to the entire population, that we were not fully able to examine the role of these variables.
Having an unplanned pregnancy was not associated with depressed mood in pregnancy, although it has been found to be associated with postnatal depression in South African peri-urban settlements [37
]. Smoking in pregnancy and alcohol use were not associated with depressed mood in the multivariate model, although both reached significance in the bivariate analysis. This is consistent with research from several countries, where an association between depression and substance abuse is well documented [32
]. In addition to Fetal Alcohol Syndrome, co-morbid alcohol use and mental disorders have been shown to have other negative consequences for infant health, with women diagnosed with co-morbid substance use disorders and psychiatric disorders being more likely to deliver low birth weight and preterm infants than those with either of these conditions alone [43
]. Furthermore, women with higher levels of depression often continue to use alcohol despite knowing they are pregnant and clinician advice against such use [44
], which has critical implications for infant health in South Africa where we have the highest rate of Fetal Alcohol Syndrome in the world [45
]. Smoking in pregnancy also places unborn infants at greater risk for late foetal and neonatal mortality, and low birth weight [47
]. The crude association between substance use and depressed mood supports the argument that effective treatment of co-occurring conditions should involve the integration of mental health and substance abuse treatment services in a cohesive and unitary system of care [48
To the best of our knowledge, this is the first study in South Africa to examine the prevalence and correlates of depressed mood in pregnancy. However, several important limitations should be noted. This study lacked clinical validation of the EPDS, and is therefore subject to error that arises from false positives and negatives inherent when using screening tools. The cross sectional design of this study does not allow us to ascertain causality, and longitudinal prospective research is needed in South Africa to fully understand the nature of social factors in antenatal depression, and the impact of antenatal depression on maternal and child health. Future research might examine threatening life events and extreme societal stressors, which were not investigated in the current study, but have been found to influence maternal depression [36
]. Finally, research examining the relationship between antenatal depression and child health in South Africa is needed.
The WHO has advised that health policy integrate mental health care into primary health care settings [50
]. Although further research is needed to establish the scalability and effectiveness of interventions for depression in community contexts, this study provides an important step in documenting the need for antenatal screening for depression. Pregnancy is a time in many women's lives when they are most likely to access the health system by way of antenatal care, and is therefore a plausible time to implement screening and intervention. Given the high prevalence of antenatal distress, early intervention may have important child health implications. Antenatal depression heightens the risk of postpartum depression, and both antenatal and postnatal depression impact on child outcomes. While maternal mental health is currently a low priority in the health care practises of most LAMI countries, the findings of this paper highlight the importance of addressing mental health in antenatal care.