In this study, we examined maternal mood symptoms, and psychosocial and behavioral factors in pregnancy with five neonate outcomes. The first main finding is that mood symptoms are not significantly related to neonatal outcomes, or marginally related as in the case of anxiety and low Apgar score at 5 minutes. The second finding is that psychosocial and behaviors factors as well as primiparous status are strongly associated with neonatal outcomes, especially SGA.
We found that antenatal depression is not related to SGA/PTB/LBW/low Apgar score that is in agreement with prior studies (16, 18, 58, 59), but in contrast to others (12, 60, 61). The major reasons for the divergent findings may be related to differences in the measurement of depression, gestational age, settings, and the samples. For example, a study with 791 women in the US assessed depression using the Center for Epidemiological Studies Depression Scale (CESD) in their early pregnancy (around 10 weeks gestation) (61). Studies found that CESD tends to produce higher scores and more false-positive results in symptomatic pregnant and postpartum women (62-64). In this diverse sample of 38.1% Caucasian, 28.6% Asian or Pacific Island, 21.0% Hispanic, and 6.8% African American women, a positive association between depression and PTB was found. Similar findings were reported in a study including 959 Chinese women in late pregnancy using the Beck Depression Inventory to assess women’s depressive status (65). Berle et al. (58) found a negative association between depression and PTB in 680 Norwegian women at 16 weeks gestation by the Hospital Anxiety and Depression Rating Scale. In addition, the positive relationship between antenatal depression and neonatal outcomes in developing countries was proposed to be related to low socioeconomic status in women who face a greater challenge of comorbid risk factors (e.g., maternal undernutrition) (66, 67). A meta-analysis of 29 studies (68) investigated possible moderators of neonatal outcomes, and found the country in which the study was conducted (developed or developing country) was a significant moderator of the association between antenatal depression and LBW. However, Goedhart et al. (2010) conducted a study of 8,050 women at 12 weeks of pregnancy in Holland, and found a positive relationship between perinatal depression and neonatal outcomes. Furthermore, in a study by Nasreen et al. (11), 720 women from two rural subdistricts of the developing country of Bangladesh were assessed in their third trimester using the EPDS to determine depressive status, and a significant relationship between antenatal depression and LBW was found while controlling for poverty and maternal nutritional status. The mechanism of impact of antenatal depression on neonatal outcomes is not well understood, and more research is required.
Among the mood symptoms, elevated anxiety was associated with low Apgar score at 5-minutes although this did not survive signficance when adjusting for maternal age and marital status. Anxiety is closely related to stress, and a higher level of stress was associated with low Apgar score (1-minute) in our study. Potential causal pathways through which prenatal anxiety and stress may lead to adverse neonatal outcomes have been proposed. One potential mechanism was identified as changes in maternal hypothalamic–pituitary–adrenal (HPA) axis activity. Increased maternal HPA axis activity has been observed during the perinatal period (69). However, experiencing elevated levels of anxiety and stress during pregnancy may contribute to an increase in stress hormones, such as cortisol and catecholamines (70). The release of stress hormones has also been found to cause changes in immunologic functioning and uterine blood flow during human pregnancy, thus increasing vulnerability to preterm birth, SGA, and low BW (71-76). However, not all studies found such an association (16, 58), which might be related to the timing of when antenatal anxiety and stress were measured in pregnancy, and what instruments were utilized (77, 78) while others suggest that the mechanisms of the association between stress and neonatal outcomes need to be further investigated (79, 80).
To the best of our knowledge, this is the first study to report the relationship between antenatal MI and neonatal outcomes, and we did not find a significant relationship. It may be that MI affects neonatal outcomes through depression, anxiety, or stress since MI is related to depression, anxiety, and stress as reported in clinical samples (19, 81) and perinatal women (21, 82). To date, the possible role of antenatal MI in fetal intrauterine development remains unexplored. More studies are required in order to understand the relationship between antenatal MI and neonatal outcomes.
The association between lack of social support during pregnancy and poor neonatal outcomes has been documented according to a systematic review (83). Our findings further support and extend previous evidence on the effect of low social support on the occurrence of adverse neonatal outcomes. During early pregnancy, women experience tremendous changes physically and psychologically which require major adjustments, and social support plays a crucial role to help women cope with the transition to motherhood (84, 85). Lack of social support from partner, family and/or friends can be reflected on lack of social stability and social participation, which has a very negative impact on the psychological well-being of pregnant women (86, 87). While the mechanism of the association between antenatal social support and neonatal outcomes is not fully understood, some proposed that effects of social support on neonatal outcomes maybe by increasing maternal stress, probably via the pathway of biological stress systems including HPA axis activity (88, 89).
Smoking was a risk factor for SGA in the current study, which replicated previous studies (90-92). Antenatal cigarette smoking leads to fetal exposure to nicotine, which crosses the placenta and leads to a 15% higher concentration than in maternal blood (93, 94). Nicotine interferes with normal placental function, and reduces uterine blood flow by an average of 30 to 49%, which causes a deprivation of nutrients and oxygen, resulting in fetal hypoxia and malnutrition, and may lead to intrauterine growth restriction (93, 95).
Our study found that being primiparous was associated with LBW and SGA, which is consistent with some studies (96). A meta-analysis of 41 studies found that being primiparous increased a woman’s risk of having a baby with LBW and SGA (96). Parity influences the growth of the placenta and its efficiency, which is related to uterine blood flow, oxygen availability, nutrient exchange, and endocrine regulation of the fetus (97, 98).
There were several limitations to the current study. First, although this is a relatively large sample, the participants were predominantly Caucasian, married, with post-secondary education, and higher family income, which limits the generalization of the findings. According to the 2016 Census of Canada (99), Aboriginal people accounted for 15.6% of the total population of Saskatchewan compared with 7.2% in this sample. Second, the measure of depression, anxiety, MI, and other psychosocial and behaviour variables relied on participants’ subjective report, which could be influenced by women’s current thoughts, feelings, and consideration of social desirability particularly, reporting antenatal smoking, alcohol consumption, and drug use (100, 101). Third, MI holds a temporal property since mood fluctuations can change from moment to moment, which is unlikely to be recalled accurately, such as which day and what time during the day it occurred (102). Two recent studies reported that paper-and-pen measures of MI do not agree with smartphone measured MI (103, 104). Finally, the VAS used to assess antenatal MI is not previously validated. Due to a lack of validated instruments in measuring perinatal MI, studies often utilize non-validated measures (105, 106). There is a need for validating existing instruments in perinatal women or developing assessment tools that are specifically relevant to perinatal MI.