Maternal age and socioeconomic differences in antenatal and postpartum depression

Abstract Background Low socioeconomic status increases the risk of perinatal depression, but the role of maternal risk factors in this inequality is unclear. We examined the contribution of maternal risk factors to socioeconomic differences in perinatal depression, investigating whether interventions should target certain age and socioeconomic groups. Methods We conducted a register-based study in Finland using the Finnish Medical Birth Register, Hospital Discharge Register, and Statistics Finland data on 932 671 women who gave birth from 2000 to 2015. Socioeconomic status was categorised according to the Classification of Socioeconomic Groups 1989 in Statistics Finland. We computed multivariable logistic regression models to estimate socioeconomic differences in perinatal depression and calculate the contribution of maternal risk factors to these associations. We measured interactions on both multiplicative and additive scales. Results Adjusted odds ratios for antenatal and postpartum depression were highest among women under 20 years of age. Compared with upper-level employees, women in manual occupations, students, and long-term unemployed women showed increased risks of antenatal and postpartum depression. Socioeconomic differences were mainly attributed to marital status, smoking, and maternal obesity. Interaction analyses indicated positive additive interactions in women aged 25-29 years and 35 years or older with lower socioeconomic status levels for antenatal and postpartum depression, whereas negative interactions were observed among teenage mothers. Conclusions The associations of socioeconomic status with perinatal depression were mainly explained by marital status, smoking, and maternal obesity. Primordial risk factors prevention should be reinforced at the population level from the beginning of the reproductive years. Simultaneously, individual-level intervention is needed among women with high absolute risk in the mid and later reproductive years. Key messages • Socioeconomic differences in perinatal depression are largely explained by modifiable maternal risk factors, particularly marital status, smoking, and maternal obesity. • To reduce inequalities in perinatal depression, early prevention at the population level should be combined with targeted interventions for high-risk women in their mid and later reproductive years.