Association of a serotonin transporter gene polymorphism (5-HTTLPR) and stressful life events with postpartum depressive symptoms: a population-based study

Abstract

We conducted a cross-sectional study nested within a cohort study with 276 postpartum women to evaluate the role of a serotonin transporter gene polymorphism (5-HTTLPR) and the stressful life events (SLE) on the risk of postpartum depression (PPD) symptoms in a community sample. Participants were assessed between 45 and 90 days after delivery with the Edinburgh Postnatal Depression Scale (EPDS) and the Mini International Neuropsychiatric Interview (MINI). Data regarding socio-demographic variables, alcohol consumption, tobacco smoking and SLE occurring during pregnancy, were also collected. In the adjusted analysis, the women carrying the long (L) allele (LL) who experienced SLE showed higher prevalence ratios (PR) for PPD symptoms (EPDS ≥13) than those with two copies of the short (S) allele (SL) (PR = 9.91; 95% confidence interval: 1.70–57.87). In contrast, a trend of association was found between prior history of major depressive disorder (MDD) and the S allele carrier status (p = 0.07). No association was found between the formal diagnosis of current MDD and the 5-HTTLPR genotypes. In line with previous reports, we find in this sample that the L allele carrier status was associated with a heighten risk of depressive symptoms in postpartum when SLE were experienced during pregnancy.

• 5-HTTLPR
• postpartum depression
• serotonin transporter gene polymorphism
• stressful life events

Current knowledge in the topic

• In general population, it has been shown that individuals carrying the 5-HTTLPR S allele who had experienced adverse life events exhibited an increased risk for MDD, compared with carriers of the L allele.

• The role of 5-HTTLPR polymorphism in PPD population was investigated, giving rise to mixed results.

• Depressive symptoms in early postpartum were associated with the presence of the L allele in some studies, but not in others.

What this study adds

• Our study is in line with the finding that the depressive symptoms in postpartum period might be related to the L allele carrier status.

• The occurrence of stressful life events during the pregnancy heightens the risk of MDD in women with L allele in our sample.

• There was a trend of association between past episodes of depression and the carriers of the S allele, suggesting that depressive symptoms that occurred in postpartum have a distinct etiopathogenesis from peripartum recurrence in women with prior history of MDD.