Psychosocial stress in pregnancy and preterm birth: associations and mechanisms.
OBJECTIVE
Psychosocial stress during pregnancy (PSP) is a risk factor of growing interest in the etiology of preterm birth (PTB). This literature review assesses the published evidence concerning the association between PSP and PTB, highlighting established and hypothesized physiological pathways mediating this association.


METHODS
The PubMed and Web of Science databases were searched using the keywords "psychosocial stress", "pregnancy", "pregnancy stress", "preterm", "preterm birth", "gestational age", "anxiety", and "social support". After applying the exclusion criteria, the search produced 107 articles.


RESULTS
The association of PSP with PTB varied according to the dimensions and timing of PSP. Stronger associations were generally found in early pregnancy, and most studies demonstrating positive results found moderate effect sizes, with risk ratios between 1.2 and 2.1. Subjective perception of stress and pregnancy-related anxiety appeared to be the stress measures most closely associated with PTB. Potential physiological pathways identified included behavioral, infectious, neuroinflammatory, and neuroendocrine mechanisms.


CONCLUSIONS
Future research should examine the biological pathways of these different psychosocial stress dimensions and at multiple time points across pregnancy. Culture-independent characterization of the vaginal microbiome and noninvasive monitoring of cholinergic activity represent two exciting frontiers in this research.
Gabriel D
GD
Shapiro
William D
WD
Fraser
Martin G
MG
Frasch
Jean R
JR
Séguin
D001007:Anxiety / Q000523:psychology; D005260:Female; D005865:Gestational Age; D006728:Hormones; D006801:Humans; D007239:Infections; D007249:Inflammation / Q000150:complications; D008019:Life Style; D008425:Maternal Behavior; D064307:Microbiota; D009422:Nervous System Diseases / Q000150:complications; D009490:Neurosecretory Systems; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000523:psychology*; D012307:Risk Factors; D012944:Social Support; D013315:Stress, Psychological / Q000150:complications*
D006728:Hormones