Preterm birth as a risk factor for postpartum depression: A systematic review and meta-analysis

Highlights

• Mothers of preterm infants are at higher risk for postpartum depression.

• Findings supported the association between preterm birth and postpartum depression.

• Methodological heterogeneity among studies might have impacted on results.

• Integrative models are needed to provide consistent evidence of such association.

Abstract

Background

This systematic review aimed to critically analyze the studies that explored preterm birth as risk factor for postpartum depression in the last 10 years.

Methods

Two independent researchers performed a systematic review of indexed studies in PubMed/Medline, Web of Science and PsycInfo database. The PRISMA for reporting systematic review model was used to conduct data extraction. A meta-analysis was performed including a sub-group of studies.

Results

The final sample consisted of 26 studies and 12 were included in the meta-analysis. Most of the studies supported the association between preterm birth (PTB) and postpartum depression (PPD). However, 8 studies did not find such association and, even among studies with positive findings, results were heterogeneous, given the methodological discrepancies among the studies. The meta-analysis provided evidence of higher risk for PPD among mothers of preterm infants in assessments performed up to 24 weeks after childbirth.

Limitations

Most of the studies did not consider the role of important confounding variables, such as previous history of depression. Heterogeneity of assessment tools and cut-off scores were also considered a limitation.

Conclusions

Further prospective population-based studies with an integrative approach of PPD are needed to provide consistent evidence of such association. Important confounding variables and biological measures implicated in PPD should be considered. Our findings highlight the importance of maternal mental health care in this target population, as preterm birth experience seem to affect both babies and mothers. We encourage PPD assessment for mothers of preterm infants, especially in the early postpartum period.

Introduction

Postpartum depression (PPD) has received greater attention lately, as it has been recognized as one of the most common morbidity in the perinatal period (O'Hara and Wisner, 2014). Besides it´s prevalence, estimated around 15%, PPD is considered a devastating morbidity, as it affects not only mother´s health (Gavin et al., 2005), but also might impact on child's development and parenting behaviors (Flynn et al., 2004). PPD´s etiology is still not totally clear, and, therefore, efforts towards identification of predictors are relevant. Predicting women at risk for PPD is a growing field of research, contributing to prevention and early detection (Guintivano et al., 2018). So far three meta-analyses considered risk factors for PPD (Beck, 2001, O'hara and Swain, 1996, Robertson et al., 2004). Depression and anxiety during pregnancy, personal or familiar history of depression, stressful life events and low social support have been strongly associated to postpartum depressive symptomatology (Robertson et al., 2004). However, neither of these meta-analyses assessed preterm birth as an independent predictor for PPD; prematurity was considered among other obstetrical variables that were found to be small risk factor for PPD (Robertson et al., 2004).

Preterm birth (PTB) is one the most frequent obstetric complication in the peripartum period. It is considered a global public health issue, as it is the leading cause of neonatal deaths worldwide (Blencowe et al., 2012) and responsible for great financial cost to public health systems. According to a recent review, the economic cost in USA related to preterm birth was around U$ 26 billion dollars (Frey and Klebanoff, 2016). Preterm delivery is associated to many unfavored outcomes to both mother and infant, such as increased psychological distress for parents (Carson et al., 2015, Singer et al., 1999) and child cognitive impairment (Bhutta et al., 2002, Oudgenoeg-Paz et al., 2017). PTB is defined by the World Health Organization as the childbirth before the 37th week of gestation is complete. It is stratified in three degrees of severity, according to gestational age (GA) at birth: extremely preterm (GA < 28 weeks), very preterm (GA = 28–32 weeks), moderate to late preterm (GA = 32–37 weeks) (World Health Organization, 2012). It is known that the earlier the gestational age at birth, greater the risks of neonatal mortality (Mathews et al., 2013) and morbidities (Stoll et al., 2010). Rates of preterm birth worldwide is 11.1%, ranging from 5% in some European countries to 18% in several African countries (Blencowe et al., 2012).

Both PPD and PTB are relevant health issues in the peripartum period and their associations have been previously explored, providing inconsistent results. While some studies have found preterm birth to be a risk factor for PPD (Drewett et al., 2004, Kersting et al., 2004) others have not found such association (Forman et al., 2000). One systematic review investigated studies published until 2008 on prevalence and risk factors associated to postpartum depressive symptoms in mothers of premature or low birth weight (LBW) infants (Vigod et al., 2010). The study concluded that mothers of preterm infants are at higher risk of depression than mothers of full-term infants in the immediate postpartum period, continued throughout the first year postpartum for mothers of very-low-birth-weight infants (Vigod et al., 2010). Authors highlighted the methodological variability among the studies included in the review. Important limitations were presented as many studies assessed relatively small samples (n < 50), and only two controlled for gestational depression (Vigod et al., 2010). Besides, this systematic review included studies without comparison group, which also might have limited the interpretation of results. In general, the increasing interest in this field is represented by the great number of studies published recently on the association between PTB and PPD. It is noteworthy that recent studies have assessed greater sample of mothers and used more robust analytical approach.

Thus, this systematic review aimed to critically analyze the studies that explored preterm birth as risk factor for postpartum depression in the last 10 years. We hypothesized that the association between PTB and PPD will be confirmed, but methodological differences among the studies might impact on results.