Is mode of delivery associated with postpartum depression at 6 weeks: a prospective cohort study W Sword, a C Kurtz Landy, b L Thabane, c,d S Watt, e P Krueger, f D Farine, g G Foster c,d a School of Nursing, McMaster University, Hamilton, ON, Canada b School of Nursing, York University, Toronto, ON, Canada c Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, ON, Canada d Biostatistics Unit, St Joseph’s Healthcare, Hamilton, ON, Canada e School of Social Work, McMaster University, Hamilton, ON, Canada f Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada g Department of Obstetrics and Gynaecology, Mount Sinai Hospital and University of Toronto, Toronto, ON, Canada Correspondence: Dr W Sword, School of Nursing 3H48B, McMaster University, 1200 Main Street West, Hamilton, ON L8N 3Z5, Canada. Email sword@mcmaster.ca Accepted 10 February 2011. Published Online 13 April 2011. Objective To examine the relationship between delivery mode and postpartum depression at 6 weeks following hospital discharge. Design A prospective cohort study. Setting Eleven hospitals in Ontario, Canada. Sample A total of 2560 women ‡16 years of age who delivered singleton, live infants at term. Methods Women completed a questionnaire in hospital and 74% (n = 1897) participated in a structured telephone interview 6 weeks after discharge. Additional data were extracted from labour and delivery records. Generalised estimating equations (GEEs) were used to investigate factors associated with postpartum depression. Main outcome measure Women were screened for depression at 6 weeks following hospital discharge using the Edinburgh Postnatal Depression Scale (EPDS). A score of ‡12 on the EPDS was used as a measure of the primary outcome, depression. Results Mode of delivery was not independently associated with postpartum depression, and did not factor into the main-effects model. The multivariable analysis identified 11 predictor variables for depression: young maternal age (OR 5.27; 95% CI 2.73–10.15); maternal hospital readmission (OR 3.02; 95% CI 1.46–6.24); non-initiation of breastfeeding (OR 2.02; 95% CI 0.99–4.11); good, fair, or poor self-reported postpartum health (OR 1.82; 95% CI 1.19–2.80); urinary incontinence (OR 1.79; 95% CI 1.06–3.03); multiparity (OR 1.59; 95% CI 1.22– 2.08); low mental health functioning (OR 1.20; 95% CI 1.15– 1.25); low subjective social status (OR 1.16; 95% CI 1.02–1.33); high number of unmet learning needs in hospital (OR 1.12; 95% CI 1.03–1.22); low social support (OR 1.06; 95% CI 1.03–1.09); and low physical health functioning (OR 1.03; 95% CI 1.003– 1.055). An exploratory interaction model revealed that caesarean section was associated with higher odds of becoming depressed in Canadian-born women, but that in women born outside of Canada it was associated with a lower risk of becoming depressed. Conclusions Delivery mode had no significant impact on the development of postpartum depression in the main-effects model. However, it may interact with place of birth and other unmeasured factors to create a risk for depression. Keywords Caesarean section, delivery mode, postpartum depression, risk factors. Please cite this paper as: Sword W, Kurtz Landy C, Thabane L, Watt S, Krueger P, Farine D, Foster G. Is mode of delivery associated with postpartum depression at 6 weeks: a prospective cohort study. BJOG 2011;118:966–977. Introduction Depression in women during their childbearing years is a major public health concern. 1,2 Because childbirth is a complex life event associated with numerous biopsychoso- cial changes, it may trigger psychiatric disorders in women with predisposing genetic or psychosocial vulnerabilities. 3 Although the Diagnostic and Statistical Manual for Mental Disorders (DSM IV) specifies postpartum depression as occurring within 4 weeks of childbirth, researchers and cli- nicians have expanded the definition to include depression without psychotic features present within the first year following childbirth. 4 A systematic review of the prevalence and incidence of perinatal depression indicated that as 966 ª 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology ª 2011 RCOG DOI: 10.1111/j.1471-0528.2011.02950.x www.bjog.org Maternal medicine