Effect of a Nonoptimal Cervicovaginal Microbiota and Psychosocial Stress on Recurrent Spontaneous Preterm Birth.

· CST IV, a nonoptimal microbiota, is associated with increased odds of recurrent spontaneous preterm birth.. · Adjustment for perceived stress amplified associations between CST IV and recurrent spontaneous preterm birth.. · Identification of modifiable psychosocial factors may unveil novel nonpharmacologic interventions to decrease recurrent preterm birth..