ASPECTOS SENSORIALES

Research has found the incidence of post-natal depression to be greatest in the first three months after birth (O’Hara & Swain, 1996; Pope, 2000; Beck, 2001; Beck & Driscoll, 2006) and it has been suggested that about 4% of women show little improvement after one year (Hauptberger, 1997), with a 20-30% recurrence rate described with subsequent births (O’Hara & Swain, 1996; Pope, 2000).

Reported estimates for the prevalence of PND have varied greatly depending on the design of studies, the recruited sample size, the timing of assessments and the use of different diagnostic criteria or rating scales (Pope, 2000). In a meta-analysis of 59 studies O’Hara & Swain (1996) has found the prevalence rate to be 13% and it is generally accepted that PND affects between 10 and 20% of all childbearing women (Beck, 2006; Warren & McCarthy, 2007).

From a Australian perspective, screening of a sample of first time mothers, approximately 6 weeks after childbirth, indicated that as many as 25% were at risk of experiencing depression, and 9 to 15% were suggested to be at a risk of severe depressive symptoms (Horan-Smith & Gullone, 1998). Other Australian studies have shown prevalence rates of PND to be 9% at six weeks after birth (Stamp & Crowther, 1993), 14% at four months (Astbury et al, 1994) and 15.4% at eight months (Small et al, 1994).

TABLE 4 – FACTORS CONTRIBUTING TO THE ONSET ON POSTNATAL DEPRESSION

Authors Sample Setting Method Results Critiques Hickey et al

1997

All 749 women delivering over a 3 month period were recruited. Of the 522 participants, 425 women completed the study. Tertiary referral hospital in western Sydney, Australia

Prospective cohort design consisting of an initial interview and six-weekly assessment for 24 weeks using a self-report questionnaire and the Edinburgh Postnatal Depression Scale. Women discharged within 72 hours after birth were compared with the remaining women.

The women who were discharged within 72 hours had a significantly increased risk of developing PND (twice as high). This risk persisted when other

sociodemographic, obstetric and psychosocial risk factors were controlled for in a logistic regression analysis.

Large convenience sample. Study seeking to explore possibility of a causal of a causal link between early discharge from hospital and PND. Women assigned to early or standard discharge group, controlling for parity, social support and past history of PND. Six weekly assessments for 24 weeks after birth ensured detection of early and late onset of PND. Using the EDPS as well as a self-report questionnaire strengthened the validity and reliability of the findings.

Beck 2001 - Meta-analysis of

literature

A meta-analysis of 84 studies published in the decade of the 1990’s was conducted to determine the magnitude of the relationships between postpartum depression and various risk factors.

Thirteen significant predictors of

postpartum depression were revealed. Ten of these risk factors had moderate effect sizes while 3 had small effect sizes. The predictors ranged as follows: prenatal depression, self-esteem, childcare stress, prenatal anxiety, life stress, social support, marital relationship, history of previous depression, infant temperament, maternity blues, marital status, socioeconomic status and unplanned/unwanted pregnancy.

Meta-analysis of 84 studies published in the 1990s carried out to determine the magnitude of the relationship between PND and various risk factors. Results confirmed the findings of an earlier meta=analysis and revealed 4 new predictors of PND – self-esteem, marital status, socioeconomic status and unplanned/unwanted pregnancy. Johnstone et al 2001 490 women planning to give birth. 4 participating hospitals

A prospective study. Obstetric information was obtained from the New South Wales Midwives Data Collection, completed shortly after delivery. Personality, psychiatric history and life events information were obtained from a questionnaire administered within 1 week postpartum. Depression status was assessed at 8 weeks postpartum

None of the obstetric variables were significantly associated with increased risk of PND. However, some

sociodemographic, personality factors, past personal or familial history of depression and recent life events were found to be risk factors.

Convenience sample, obtained from 4 hospitals. Prospective study

exploring relationship between obstetric risk factors and PND. Obstetric information obtained from the women’s medical records, depression status assessed at 8 weeks postpartum. Later onset of PND than this time may have been a factor influencing results.

using the Edinburgh Postnatal Depression Scale.

Koo et al 2003

55 women who had an emergency delivery and 191 women who delivered normally at least 6 weeks postpartum. Cohort part of a previous study examining the prevalence of PND

A retrospective comparative cohort study design.

When compared with women having a non-emergency delivery, women having an emergency delivery had almost twice the risk of developing PND.

Malaysian study seeking to find out whether emergency delivery is a risk factor for PND. Multicultural sample, data divided into 2 cohorts, 55 women who had an emergency delivery and 190 who delivered normally. Multicultural sample, results may be difficult to generalize to other cultures. Robertson et al 2004 Meta-analysis of previous research findings

Systematic review Meta-analysis of existing literature to identify antenatal risk factors for postnatal depression

The strongest predictors of postpartum depression were: depression during pregnancy, anxiety during pregnancy, experiencing stressful life events during pregnancy or the early puerperium, low levels of social support, and a previous history of depression.

Meta-analysis, focus on antenatal factors. Critical approach of the literature revealed a number of methodological and knowledge gaps that the researchers recommended need o be addressed in future research. McCoy et al 2006 209 women 4 weeks postpartum 3 university medical clinics in Tulsa Okla

Data gathered at routine 4-week postnatal visits were obtained from the patient records and participants in study needed to complete the Edinburgh Postnatal Depression Scale.

Formula feeding in place of breastfeeding, a history of depression and cigarette smoking were all significant risk factors for PND.

Study exploring possible correlation between incidence of PND and the following patient characteristics: age. breastfeeding status, tobacco use, marital status, history of depression and method of delivery.

Convenience rather than random sampling, but finding support data of various other randomised findings. Population poorer than in other areas and/or indigent, this could have lead to a higher rate of PND. Also PND assessment at 4 weeks did not take into account the possibility of later onset.

Azimi- Lolaty et al, 2007

422 pregnant women

Mother Child Health Care Clinics

Participants recruited antenatally and followed up at 6-8 weeks postnatally. Administered the Edinburgh Postnatal Depression Scale.

Risk factors for PND were identified as family support, stressful life events, health of baby, perceived ability to care for the baby.

Iranian study, convenience sample of antenatal women to measure risk factors for PND for this cohort of pregnant women. Differences were found in the level of depression in self-reports and interview based measures. Cultural make up of sample may lead to a difficulty in the generalizability of results. d Rahman & Creed 2007 701 antenatal women in third trimester of pregnancy A rural sub-district of Pakistan

The Schedule for Clinical Assessment in Neuropsychiatry (SCAN) was used to identify depressed women in the third trimester of pregnancy (n = 160). These women were re-assessed at 3, 6 and 12 months postnatally. Persistently depressed women (depressed at all 3 points) were compared with the remainder. Psychiatric symptoms, disability and life events were measured using the Self-Reporting Questionnaire (SRQ), Brief Disability Questionnaire (BDQ) and a modified Life Events Checklist.

56% of mothers (73 from 129) were depressed at all points of assessment. These mothers had higher SRQ and BDQ scores prenatally and had experienced more stressful life events in the year preceding the third pregnancy trimester than the mothers whose depressive disorder resolved. Persistent depression was significantly associated also with poverty, having 5 or more children, an uneducated husband and lack of a confidant or friend.

Antenatal screening of women for depression in the third trimester of pregnancy to study antenatal depression as a risk factor for PND. Depressed women were assessed 3, 6 and 12 months postnatally and those depressed at all 3 point compared with the remainder of the sample. The use of several measures strengthened the robustness of the findings. However, sample was from one rural sub-district of Pakistan which could limit generalizability of results. Also the women were not assessed for physical conditions such as anaemia and thyroid deficiency which may have been a risk factor for PND.