OBJECTIVE: This study aimed to examine how weight and weight changes related to pregnancy were associated with depressive symptoms 11-16 years after childbirth.

METHOD: We followed 16,998 first-time mothers from the Danish National Birth Cohort up till 16 years after birth and estimated associations between depressive symptoms and pre-pregnancy body mass index (BMI) (kg m(-2)), weight changes in different time periods, and BMI-adjusted waist circumference 7 years after birth (WCBMI, cm). Depressive symptoms were estimated by the Center for Epidemiologic Studies Depression 10-item scale. Multiple logistic regression analyses were used to estimate odds ratios (OR) and 95% confidence intervals.

RESULTS: Compared with normal-weight, we found that underweight, overweight and obesity were associated with greater odds of depressive symptoms (1.29, 1.24 and 1.73, respectively). Compared with weight change ±1 BMI unit during the total follow-up period, greater odds for depressive symptoms were observed with weight loss (OR 1.14, 0.96-1.36) or gain of 2-2.99 kg m(-2) (OR 1.11, 0.92-1.33) or gain of ≥3 kg m(-2) (OR 1.68, 1.46-1.94). WCBMI > 2.2 cm was associated with greater odds of depressive symptoms (OR 1.16, 0.99-1.36) than waist circumference as predicted by BMI.

CONCLUSION: Low and high pre-pregnancy BMI, weight changes and WCBMI larger than predicted were associated with more depressive symptoms in midlife.