Economic contraction and birth outcomes: an integrative review.

BACKGROUND Previous research has demonstrated an association between economic contraction at both the individual and aggregate level, and adverse health outcomes. Proposed mechanisms include increased psychosocial stress and loss of resources. The aim of this review is to assess the quantity, validity and consistency of empirical evidence examining economic contraction and birth outcomes. METHODS Empirical, English-language articles examining the effects of economic change at either the aggregate or individual level on birthweight, length of gestation, neonatal mortality and the secondary sex ratio were identified using PubMed and ISI Web of Knowledge. Studies were organized by level of analysis and birth outcome and evaluated for internal and external validity. RESULTS One individual-level study reported a strong association between individual shift to inadequate employment and decreased birthweight. Of seven aggregate-level studies on birthweight, five exhibited moderate to strong validity but reported inconsistent findings. Similarly, findings from five studies (four with moderate to strong validity) examining rates of neonatal mortality reported inconsistent findings. Three of four moderate to strong studies reported a reduced secondary sex ratio following economic contraction. CONCLUSIONS Associations between economic contraction and birthweight, neonatal mortality and the secondary sex ratio remain speculative. Consensus on methodology is needed to compare findings across studies. Further research on economic contraction and the secondary sex ratio, as well as individual-level birthweight and length of gestation, is warranted.