Social stress predicts preterm birth in twin pregnancies.

OBJECTIVE: To investigate whether stress, anxiety and depression predict preterm birth in twin pregnancies.

METHODS: A prospective cohort study with a convenience sample of women pregnant with dichorionic, diamniotic twins. They were interviewed at 24-28 weeks using the Life Events and Difficulties Schedule and the Hospital Anxiety and Depression Scale. Corticotrophin-releasing hormone, ACTH and cortisol levels were assessed at 28 weeks. The main outcome was premature delivery; there were 42 preterm and 73 term births.

RESULTS: Preterm births (<37 weeks) were predicted by higher levels of social stress: 24/42 (57.1%) of women labouring prematurely and 14/73 (19.2%) of those giving birth at term had experienced a severe life event and/or marked social difficulty in the preceding year (<0.001). In logistic regression controlling for age, anxiety and depression, the experience of a severe life event during the year preceding the interview (OR =15.6; 95%CI: 3.0 to 80.8) and a marked difficulty in a close relationship (OR = 17.8; 95%CI: 1.7 to 192) were the factors predicting preterm birth. Levels of CRH, cortisol and ACTH at 28 weeks were not associated with preterm birth. Of the women whose pregnancy lasted less than 34 weeks (early preterm birth) 15/16 had experienced a severe life event and/or marked social difficulty compared to a third (9/26) of those delivering at 34-36 weeks (late preterm birth) and 14/73 of women whose pregnancy reached term (p < .001).

CONCLUSION: Experience of severe social stress predicts preterm birth in twin pregnancies.