BACKGROUND

Depression is much commoner in women than men (Weissman, 1995). The high prevalence of depression in women is most likely due to a combination of gender-related differences in cognitive styles, certain biologic factors and a higher incidence of psychosocial and economic stresses in women (Korstein,1997). Depression during the perinatal period is common and it is debated if it is of a different type. Perinatal depression is often divided into antenatal and postnatal depression.

Postnatal Depression: Depression up to one year after delivery is called postpartum depression or postnatal depression. Postnatal depression is a mental and behavioural disorder associated with the puerperium, typically commencing within 6 weeks of delivery according to the International Classification of Disease-ICD-10(World Health Organisation, 1992). It is characterised by episodes of irritability, guilt, exhaustion, anxiety, sleep disorders and somatic symptoms which have a disabling effect on mothers, children and families of sufferers, following childbirth (Green et al., 1990). The cause of postpartum depression remains unclear with diverse researchers suggesting a multi-factorial aetiology (Ross et al., 2004). However, epidemiological studies strongly support the importance of psychosocial variables (O'Hara & Swain 1996, Beck 2001). In particular, a recent meta-analysis of 84 studies showed several risk factors including low levels of social support, stressful life events, childcare stress, low self esteem, low income, and marital dissatisfaction (Beck 2001). Buuljen (2007) concluded that one of the most notable explanations for PND was the lack of social support.

Social support: Social support is defined as help in difficult life situations. Social support is a concept that is generally understood in an intuitive sense, as the help from other people in a difficult life situations. There are different types and sources of social support. House described four main categories of social support: emotional, appraisal, informational and instrumental (House, 1981). Based on Barrera's (1981,2000) theoretical model, social support in the perinatal period can be defined as activities directed at assisting pregnant women and new mothers in mastering emotional distress, sharing tasks, giving advice, and teaching parenting skills, including the provision of material aid.

Social support seems to be one of the most important protective factors against depression in women at all periods of their lives; lack of social support has been consistently associated with depression in women of childbearing age. In order to understand better the relationship between social support and postnatal depression in women, I did a systematic review.

Social support and postnatal depression: In my sytematic review I was able to identify 20 papers that used a longitudinal design to assess the association between social support in pregnancy and postnatal depression. Among those that measured social support during the antenatal period, Brugha et al (1998), Glasser et al (2000), Bernazzani at al (1997) and Webster at al (2000) measured social support at less than 28 weeks of gestation; whereas Rahman et al (2003) and Chee et al (2008) took their measurements at the third trimester, between thirty four to forty weeks of gestations. Brugha et al (1998), Glasser et al (2000) and Webster et al (2000) found strong association between low social support at antenatal period and high EPDS score at postnatal period. Rahman et al (2003) found that support related to childcare by at least one of family member was associated with less PND, and the finding was almost similar to the study done by Chee et al (2000) when she found low instrumental support was associated with less PND but not for emotional support. Therefore from the studies we noticed that the measurement of social support was quite general when it was measured at early gestations, but when it was measured at late gestations the authors started to focus on type of social support.

Therefore my proposed study will be base on the objectives below.

OBJECTIVES

1. To study the association between social support in pregnancy and postnatal depression

2. To investigate the association between different types of social support in pregnancy and postnatal depression

3. To study if other psychological and social factors in pregnancy may contribute to postnatal depression in the presence of good social support.

METHODOLOGY

The proposed project will benefit from the rich and extensive longitudinal data obtained by Avon Longitudinal Study of Parents and Children (ALSPAC). ALSPAC is an ongoing population based study. This study will investigate the importance of social support in the ALSPAC mothers during pregnancy and the postnatal period.

Measures:

1. Depressive symptoms (mothers); antenatal and postnatal

2. Social support and social network measures

3. Personality

4. Religiosity

5. Locus of control

6. Life events

Analysis plan:

We will use complete datasets for the variables of interest. Initially I will perform a descriptive analysis of the main variables of interest during pregnancy and one year of postnatal period. I will then perform some basic cross-tabulations between social support measures during pregnancy and postnatal depression. Chi-square tests for these associations will be estimated. I will then examine the possible influence of confounding variables such as personality and life events. After this descriptive phase I will perform multivariate regression analysis to examine the association between postnatal depression and social support in pregnancy before and after adjusting for possible confounders. Potential moderating and mediating factors will also be examined. Finally I will explore applying other statistical approaches using more sophisticated models such as structural equation modelling.