Date of Award

January 2016

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Nicola L. Hawley


The role that psychosocial factors play in determining birth weight has been thought to play an analogous role as physical insults during pregnancy. In particular, maternal social support and stress have been studied separately with respect to their association with low birth weight (LBW), with more recent studies examining their interaction. The latter case has found that the level of social support reported by participants can modify the association between perceived levels of stress and LBW status. However, much of the research conducted to study and establish this relationship has mostly taken place within the high income countries (HIC) of Western Europe or the US. The current study takes place in Johannesburg, South Africa in 1990, which is dissimilar to these previous contexts which operated within mostly stable political and social systems. Objective: Examine whether an association between stress and LBW exists and if social support is an effect modifier or confounder of this relationship for this study population. Method: From the Birth to Twenty birth cohort, 1591 infants had birth weight recorded and their respective mothers self-reported social support and levels of stress in pregnancy, along with their demographic information. Also, information on the infant included sex, gestational age, Apgar score, and Caesarian delivery. Results: The adjusted logistic regression between stress and LBW did not find any significant associations (OR 0.90 95% CI 0.64-1.27). Similarly, social support and LBW were not found to be significantly associated (OR 1.09 0.81-1.47). The full model with stress and LBW testing for moderation or confounding by social support was unable to establish social support as an effect modifier or confounder of the relationship between stress and LBW. Conclusions: The findings of this study were not able to positively affirm the association between stress and LBW or the moderating effects of social support within this sample population. The lack of significant association may be due to a true lack of association between stress and LBW in this population. However, the lack of precision also maintains the possibility that a relationship may exist between stress and LBW, with or without moderation by social support. Further conclusive studies are needed to definitively establish the association between stress, social support, and LBW with greater precision in a LMIC setting.


This is an Open Access Thesis.