Cumulative life stressors and stress response to threatened preterm labour as birth date predictors

Preterm birth represents one of the main causes of neonatal morbimortality and a risk factor for neurodevelopmental disorders. Appropriate predictive methods for preterm birth outcome, which consequently would facilitate prevention programs, are needed. We aim to predict birth date in women with a threatened preterm labour (TPL) based on stress response to TPL diagnosis, cumulative life stressors, and relevant obstetric variables.

A prospective cohort of 157 pregnant women with TPL diagnosis between 24 and 31 weeks gestation formed the study sample. To estimate the stress response to TPL, maternal salivary cortisol, α-amylase levels, along with anxiety and depression symptoms were measured. To determine cumulative life stressors, previous traumas, social support, and family functioning were registered. Then, linear regression models were used to examine the effect of potential predictors of birth date.

Lower family adaptation, higher Body Mass Index (BMI), higher cortisol levels and TPL diagnosis week were the main predictors of birth date. Gestational week at TPL diagnosis showed a non-linear interaction with cortisol levels: TPL women with middle- and high-cortisol levels before 29 weeks of gestation went into imminent labour.

A combination of stress response to TPL diagnosis (salivary cortisol) and cumulative life stressors (family adaptation) together with obstetric factors (TPL gestational week and BMI) was the best birth date predictor. Therefore, a psychosocial therapeutic intervention program aimed to increase family adaptation and decrease cortisol levels at TPL diagnosis as well as losing weight, may prevent preterm birth in symptomatic women.