Postpartum depression: identification of women at risk

Transcription

1 British Journal of Obstetrics and Gynaecology October 2000, Vol107, pp Postpartum depression: identification of women at risk *D. Nielsen Forman Registrar, TP.Videbech Consultant, *M. Hedegaard Senior Registrar, *J. Dalby Salvig Registrar, *N. J. Secher Consultant *Perinatal Epidemiological Research Unit, Department of Obstetrics and Gynaecology, Aarhus University Hospital; -(Department of Biological Psychiatq, G. Psychiatric Hospital in Aarhus, Denmark Objective To identify and test the predictive power of demographic, obstetric, and psychosocial risk factors of postpartum depression. Design Community-based, prospective follow up study based on questionnaires on past history of psychiatric disease, psychological distress and social support during pregnancy and depression at four months after delivery. Obstetric files were collected at time of birth. Setting Antenatal care clinic and delivery ward, Aarhus University Hospital, Denmark. Population 6790 women giving birth between 1 January 1994 and 31 December 1995, who attended the antenatal clinic during pregnancy; 5252 (78%) completed all questionnaires. The validation population comprised 528 women enrolled immediately prior to and after the study period. Main outcome measure Postpartum depression four months after giving birth assessed by the Edinburgh Postnatal Depression Scale. Results 5.5% of the women suffered from postpartum depression, corresponding to a score of 13 or higher on the Edinburgh Postnatal Depression Scale. Risk factors identified by multivariate logistic regression analysis included psychological distress in late pregnancy (OR 6.3 [95% CI ]), perceived social isolation during pregnancy (OR 3.6 [95% CI ); high parity (OR 3.8 [95% CI ); and a positive history of prepregnant psychiatric disease (OR 2.1 [95% CI ). No association was found between pregnancy or delivery complications, and postpartum depression. The maximum predictive power of the identified risk factors was 0.3. According to these results, one out of three women who suffers from psychological distress in late pregnancy with perceived social isolation will develop postpartum depression. Conclusion Antenatal focus on psychosocial wellbeing may help to identify women at risk of postpartum depression. INTRODUCTION Nonpsychotic depression in the postpartum period is a well known clinical phenomenon, but women at risk are rarely recognised during pregnancy or at the delivery ward'.2. Prevalence varies between 8% and 15% according to the different diagnostic criteria Although the incidence in the year following childbirth does not appear to exceed the incidence of depression found in nonchildbearing population^^*^, a public health problem exists. Postpartum depression has a long term effect on mental health since it may increase the risk of continuing or recurrent depre~sion~*'@'~. Postpartum depression has also been associated with adverse effects on early infant development'"18, especially among socially disadvantaged children. Serious consequences for the child include increased risk of accidents, sudden infant death syndrome, and an overall higher frequency of hospital admission^'^-^^. ~ ~ ~ ~ Correspondence: Dr D. N. Forman, Forteledet 16, st, DK 8240 Risskov, Denmark. Numerous studies have addressed the significance of various biological and nonbiological factors in the aetiology of postpartum depression. The frequent use of retrospective study methods may explain the conflicting data available on the role of perinatal event^^^-^'. The most consistent findings link low socioeconomic status and previous psychiatric illness to postpartum depresion^,^"'^. Few attempts have been made to test the predictive power of putative risk factor^^^.'^, and none have used standardised and well validated questions. The aim of the present study was to test the value of potential risk factors measured during pregnancy and prenatal period in the prediction of postpartum depression. METHODS The population comprised a cohort of Danish speaking women attending the antenatal programme for second trimester examination. The women were delivered at the Department of Obstetrics at Aarhus University Hospital in the period from December 1993 to March RCOG 2000 British Journal of Obstetrics and Gynaecology

2 POSTPARTUM DEPRESSION 1211 Development of predictive index was based on data collected from 1 January 1994 to 31 December The model was tested using data collected in the four months immediately prior to and after this period. The study cohort comprised 6790 women who were enrolled about the 16th week of gestation. All women were asked to complete the first questionnaire which requested age, parity, socioeconomic status, medical, obstetric, and psychiatric history, use of alcohol and drugs. The questionnaire was completed at home. Two reminders were mailed to nonrespondents. At the 30th week of gestation, the women who had returned the first questionnaire were sent a second questionnaire which asked about social support, psychological distress and intake of alcohol. One reminder was mailed to nonrespondents. Screening for postpartum depression was performed at four months postpartum by a third self-administered questionnaire mailed to women who had answered the two first questionnaires. Women who had experienced pre-, pen- or postnatal fetal death were excluded. Information about pregnancy and delivery was obtained from a specific registration form filled in by the midwife immediately after delivery. All obstetric data were validated by a research midwife reviewing the hospital records. Assessment The main outcome measure was the Edinburgh Postnatal Depression Scale, which has been validated for detection of postpartum depression in community sample~~~,. Using a threshold score of 12/13, the scale has been found to have a sensitivity ranging from 68% to 86% and specificity from 78% to 96%35*37. The Fdinburgh Postnatal Depression Scale was translated into Danish and then back-translated in order to check that the questions elicited the intended information. The principal measure of psychological distress in the 30th week of gestation was the 12-item version of the General Health Questionnaire, a screening instrument designed for use in general population surveys. This score indicates the severity of psychological distress on a continuous scale. Content and concurrent validity of the 30-item version has been tested in a Danish populati~n ~.~~. Several studies have found the General Health Questionnaire an appropriate method of measuring psychological distress among pregnant women4 v4*. The General Health Questionnaire score was categorised into three levels of distress according to Goldberg *. The principal measure of social support was based on the subjective feeling of perceived social isolation, categorised into three levels: never, occasionally and often. Social support was initially covered by 15 questions. The questions addressed number of social contacts, and perceived social support from close friends and family. However, analyses revealed the single question to be most informative and strongest associated to postpartum depression. Analyses were conducted in three phases. Potential risk factors were identified in the study population of 6790 women. Subsequently, a predictive index was developed and tested on a smaller validation sample of 528 women enrolled in the months immediately before and after the study period. In the first phase, potential variables were evaluated for bivariate association with postpartum depression, and significant associations were subsequently entered into multivariate logistic regression analyses. The predictive power of the risk factors was summarised as a risk index, defined as a sum of the risk factors weighted by the estimated regression coefficients obtained from the logistic regression analysis. A risk index was determined for each woman. Two predictive indices were considered: one index involving only antenatal risk factors, the other involving both antenatal and perinatal risk factors. The predictive indices were applied to the validation sample in order to test validity coefficients of sensitivity, specificity and positive predictive values. Receiver-operator characteristic curves were c~nstructed~~. Statistical methods Bivariate associations were tested with Student s t test for normally distributed continuous variables, and the Mann-Whitney U tests for continuous variables not normally distributed. The x2 test was used to assess associations between postpartum depression and categorical risk factors. Logistic regression was used when multiple variables were considered simultaneouly. Odds ratios (OR) were presented with 95% confidence intervals (CI). Statistical significance was defined as two-sided P values using a significance level of 5%. The area under the receiver-operator curve was derived from the Mann- Whitney U statistic for comparing the distribution of the risk index among depressed and nondepressed women44. The project was approved by the regional committee for ethics in science. RESULTS Of the 6790 women enrolled in the study cohort, 6388 (94%) completed the first questionnaire; 5866 (86%) completed the second questionnaire; 5262 women (78%) completed all three questionnaires. Twenty-eight women were not contacted because of child death, and nine women were lost to follow up. The screening questionnaire for postpartum depression was completed by 5091 women who did not miss any items. Multivariate analysis was performed on 0 RCOG 2000 Br J Obstet Gynaecol 107,

3 1212 D. NIELSEN FORMAN ET AL fewer women because a number of women had missing data for one or more variables. Over the two year follow up period, 85 women were enrolled twice due to repeated pregnancies. In these cases only data from the first pregnancy were used. A score of 13 or above was achieved by 28 1 women, indicating a point-prevalence of postpartum depression of 5.5 (281/5091). Distribution of study variables among depressed and nondepresssed is shown in Tables 1-3. The variables are grouped into sociodemographic characteristics, psychopathological and social support status, and perinatal events. Bivariate associations are provided as unadjusted odds ratios for all study variables. Subsequent multivariate associations are shown in Table 4, including the variables for both antenatal and perinatal risk factors. These results show that psychological distress is the variable with the strongest association with postpartum depression with an odds ratio of 6.3 (449.1) for the most distressed group of women, compared with women in the low distress category. Social isolation showed on multivariate level a markedly lower but still strong association with postpartum depression with an odds ratio of 3.6 ( ), compared with women who did not report feelings of social isolation. Among other variables, only high parity and prepregnant history of psychiatric disease were significantly associated with postpartum depression increasing the women's risk three- and twofold respectively. It is notable that no perinatal event or paediatric complications remained significant risk factors when applied into multivariate analysis. The two indices performed almost identically with an area under the receiver-operator curve of 0.72 for antenatal index, and 0.71 for the combined antenatal and postnatal index (Fig. 1) and a maximum positive predictive value of about 30%, assuming a prevalence of 5.5% (Fig. 2). Analyses of nonrespondents showed that women who did not complete the Edinburgh Postnatal Depression Scale had a significant higher frequency of especially psychosocial risk factors than women who had completed the Edinburgh Postnatal Depression Scale (Table 5). DISCUSSION To our knowledge this is the largest study of postpartum depression. The systematic, prospectively collected information about potential risk factors among a nonselected population and use of a standardised and well validated screening instrument provided the possibility of estimating the prevalence of postpartum depression in a general obstetric population. In addition, the predictive power of some uncommon potential risk factors was estimated. The point prevalence of 5.5% with postpartum depression seen in this study is slightly lower than that observed in other Scandinavian studies with comparable study population^^^"^. Thus, a prevalence of approximately 7% using a similar cut off score of 12/13 on the Edinburgh Postnatal Depression Scale has been reported. This may in part be explained by differences in the timing of assessment. In our study prevalence was assessed at four months postpartum, and previous studies have found an increased rate of onset in the first three months following delivery". Thus, an earlier assessment could have found a higher prevalence8. Table 1. Sociodemographic characteristics by postpartum outcome. Values are given as %, unless otherwise stated. Variable Depressed Nondepressed Unadjusted odds ratio (95% CI) Age < % 0.6% 1.4 ( ) % 11.5% 1.6 ( ) % 38.8% 1.0 (reference) % 34.8% 1.2 ( ) > % 14.2% 1.4 ( ) Mean age P = 0.69* Parity % 53.1% 1 (reference) % 44.9% 1.2 ( ) >2 6.4% 2.0% 3-6 ( ) Marital status Solitary 5.2% 2.5% 2.2 ( ) Maniedlcohabiting 94.8% 97.5% 1 (reference) Working status Welfare payments 17.6% 6.0% 3.6 ( ) Unemployment relief 17.9% 15.3% 1.4 (1.o-2.0) Working/ sick leave/ student 64.4% 78.7% 1 (reference) *Students t test. 0 RCOG 2000 BrJ Obstet Gynaecol 107,

4 POSTPARTUM D EP RE S S ION 1213 Table 2. Psychopathological status and social support by postpartum outcome. Values are given as %, unless otherwise stated. GHQ = General Health Questionnaire. Variable Depressed Nondepressed Unadjusted odds ratio (95% CI) Positive history of psychiatric disease 19.6% 7.3% 3.1 ( ) Family history of psychiatric disease 20.2% 14.0% 1.6 ( ) Level of psychological distress, third trimester* High 45.2% 13.9% 7.3 ( ) Moderate 25.1% 19.3% 2.9 (2.140) LOW 29.7% 6643% 1 (reference) Mean score of GHQ P = 0@03' Alcohol intake, third trimester (glasses per week) % 2.3% 1.3 ( ) % 31.3% 0.7 ( ) <1 73.8% 66.4% 1 (reference) Present or prior drug abuse 2.1% 1.3% 1.7 ( ) Perceived social isolation Always 10.6% 2.0% 9.0 ( ) Occasionally 68.1% 62.7% 1.8 ( ) Never 21.2% 35.3% 1 (reference) *Levels of psychological distress: GHQ score 4 =high; GHQ score 2-3 = moderate; GHQ score < 2 = low. 'Mann-Whitney U test. Table 3. Perinatal events by postpartum outcome. Variable Depressed Nondepressed Unadjusted odds ratio (95% CI) Not attending parenting classes Prior induced abortion Mode of delivery Acute caesarean section Instrumental delivery Spontaneous delivery Apgar-score< 7 by 5 min Preterm delivery (gestational week < 37 ) Low birthweight (< 2500 g) Multiple pregnancy Pregnancy complications Vaginal bleeding Premature contractions General physical discomfort Pelvic-joint complaints Sick leave due to pregnancy Any complications No complications Admission to hospital due to pregnancy complications Puerperal complications Neonatal complications Child admitted to neonatal department Congenital malformations Place of delivery Hospital Home Postnatal hospital stay (days) >5 2-5 <1 Breastfeeding Never established 524% 18.6% 6.2% % 0.4% 6.1% 4.3% 1.5% 3.6% 4.4% 0.7% 6.9% 6.6% 77.7% 13.5% 7.7% 10.6% 2.5% 99.6% 0.4% 19.4% 29.1% 51.5% 5.4% 40.2% 18.7% 5.5% 13.0% 81.5% 043% 3.8% 3.1% 2.0% 2.5% 3.7% 0.4% 5.8% 4.6% 83.1% 7.4% 7.4% 8.9% 1.O% 98.6% 1.4% 15.4% 30.3% 54.3% 2.4% 1.7 ( ) 1.O ( ) 1.1 ( ) 1.0 ( ) 1 (reference) 0.4 ( ) 1.6 ( ) 1.4 ( ) 0.7 ( ) 1.5 ( ) 1.2 (06-2.1) 1.8 (04-8.1) 1.2 ( ) 1.5 ( ) 1 (reference) 1.9 (14-2.8) 0.8 ( ) 1.2 ( ) 2.6 ( ) 0.3 ( ) 1 (reference) 1.3 (1.0-14) l(o.8-1.3) 1 (reference) 2.4 ( ) 0 RCOG 2000 Br Jobstet Gynaecol lcn,

5 1214 D. NIELSEN FORMAN ET AL Table 4. Significant adjusted odds ratio (95% CI) n = OR = odds ratio; GHQ = general health questionnaire. Antenatal information Age < > 34 Parity > Marital status Single Manidcohabiting Occupational status Welfare payments Unemployment relief Working/ student/ sick leave Past history of psychiatric disease Yes No Family history of psychiatric disease Yes No Perceived social isolation Always Occasionally Never Level of psychological distress during pregnancy' High Moderate Low Perinatal events Not attending parenting classes Admitted to hospital during pregnancy Congenital malformations Breastfeeding never established Antenatally adjusted OR (CI)* 1.2 ( ) 1.3 (04-2.1) 1.0 ( ) 1.1 ( ) 3.8 ( ) 1.2 ( ) 1.1 ( ) 1.7 ( ) 1.2 ( ) 2.1 (143.2) 1.4 ( ) 3.6 ( ) 1.5 ( ) 6.3 (449.1) 3.2 (2.147) Perinatally adjusted OR (CI)* 1.1 ( ) 1.3 ( ) 1.0 ( ) 1.1 ( ) 2-9 ( ) 1.o (06-1.4) 1.1 ( ) 1.5 ( ) 1.1 ( ) 2.1 (14-3.2) 1.5 ( ) 3.6 ( ) 1.5 ( ) 6.1 ( ) 3.1 ( ) 1.5 ( ) 1.2 ( ) 1.2 ( ) 1.5 ( ) *Column variables adjusted for all variables in column. 'Levels of psychological distress: GHQ score 4 =high; GHQ score 2-3 = moderate; GHQ score < 2 = low. The low point prevalence may also be influenced by selection bias due to the high proportion of nonrespondents. This is supported by the fact that nonrespondents had a higher frequency of risk factors, compared with women who had completed the Edinburgh Postnatal Depression Scale. With these limitations in mind, our study and previous Scandinavian studies suggest that the prevalence of postpartum depression in a nonselected Scandinavian population is lower than reported from non-scandinavian co~ntries~~*~~~~. Our study further supports previous evidence that psychosocially disadvantaged women are at high risk of developing postpartum depression. The strongest antenatal predictor was psychological distress. This indicates that postpartum depression, at least in some women, could be viewed as a continuum of depressive symptoms, deteriorating over time. The other strong risk factor associated with postpartum depression was social isolation. The strong association between lack of social support and postpartum depression has been demonstrated previously in a prospective study in a community-based study? women who did not attend parenting classes were at higher risk of subsequent postpartum depression than those who attended classes. One earlier study has confirmed this finding50. Our results do not support the suggestion that pregnancy or delivery complications per se should represent any cause for the development of postpartum depression. Thus, no obstetric risk factor could be identified on the multivariate level among the extensive amount of perinatal information collected. 0 RCOG 2000 Br JObsfet Gynaecol 107,

6 POSTPARTUM DEPRESSION , speeir&y Fig. 1. Receiver-operator characteristic curve for antenatal and perinatal indices. These findings contradict previous studies concerning the role of perinatal events, especially caesarean section23.24s ur study includes both emergency and elective caesarean section, since emergency caesarean section may constitute a more traumatic experience. To facilitate comparisons with other studies, elective and emergency caesarean section were also combined, but remained unassociated with postpartum depression. The design of the present study allowed for testing the predictive power of the identified risk factors on a sample not used for extracting the predictive variables. As seen in Figs. 1 and 2, the maximum positive predictive value of 0.30 corresponds to a sensitivity and specificity of 0-79 and 0.50, respectively. Psychological distress and social isolation were by far the strongest risk factors for postpartum depression. Thus, the results suggest that with an estimated prevalence of 5-5%, approximately one out of three women with severe psychological problems and social isolation in late pregnancy after delivery will develop postnatal depression. The antenatal prediction is not likely to be improved significantly by incorporating perinatal parameters. As seen, these factors did not improve the predictive performance (Figs. 1 and 2). The present study does not take into account possible aetiological factors operating from delivery and up to the time of assessment four months postpartum. Part of the demonstrated lack of precision of our prediction could thus be attributed by such potential factors. It cannot be ruled out that factors other than the ones investigated may be able to improve the detectability; however, we have included and tested all relevant risk factors known from the literature. To our knowledge only one prior study has tested antenatal prediction of postpartum depression on a larger sample34. However, in contrast to the previous study, we have assessed the predictive power of psychological morbidity and lack of social support in relation to postpartum depression using a standardised and well validated instrument. Many screening questionnaires have been developed to assess psychosocial factors. The General Health Questionnaire is, in our opinion, the best validated and most widely used instrument to assess psychological morbidity and could in its short 12-item version prove to be an important antenatal care tool for detecting women at risk for postpartum depression. The fact that the condition is seldom identified in the postpartum period54 stresses the importance of antenatal strategies targeted at the high risk group. Twenty percent of severe postnatal depression become chronic and delay of treatment is the greatest factor in the development of chronic depre~sion~~. Thus, special attention should be given to women at risk to ensure early identification and adequate treatment. Our findings CUtOffseOreS Fig. 2. Positive predictive value for antenatal and perinatal indices at different cut off scores. 0 RCOG 2000 BrJ Obstet Gymecol 107,

7 1216 D. NIELSEN FORMAN ET AL. Table 5. Differences in responders and nonrespondents to the Edinburgh Postnatal Depression Scale. Variable Nonrespondents (a) Responders (%) P Young age (20-24) High parity (> 2) Low working status Past history of psychiatric disease Family history of psychiatric disease Lack of confidence Psychological distress (high level) Attending parenting classes Admission to hospital due to pregnancy complications Congenital malformations ~0001 0~0001 0~ o*oo01 0~ suggest that screening for psychological morbidity in late pregnancy, as well as focusing on reported perception of social isolation may be useful in identifying women at risk antenatally who may develop postnatal depression. Acknowledgement This study was supported the Ministry of Health (The National Health Fund for Research and Development) and Eli Lilly (Denmark). The authors would like to thank the staff at the Perinatal Epidemiological Research Unit at the University Hospital in Aarhus for their assistance during data collection. s 1 Lepper HS, DiMatteo MR, Tinsley BJ. Postpartum depression: how much do obstetric nurses and obstetricians know? Birth 1994; 21: Cox JL, Connor Y, Kendell RE. Prospective study of the psychiatric disorders of childbirth. Br JPsychiatry 1982; 140: Kumar R, Robson KM. A prospective study of emotional disorders in childbearing women. Br J Psychiatry 1984; 144: OHara MW, Neunaber DJ, Zekoski EM. Prospective study of postpartum depression: prevalence, course, and predictive factors. J Abnorm Psychol 1984; 93: Warner R, Appleby L, Whitton A, Faragher B. Demographic and obstetric risk factors for postnatal psychiatric morbidity. Br JPsychiatry 1996; 168: Lane A, Keville R, Moms M. Kinsella A, Turner M, Bany S. Postnatal depression and elation among mothers and their partners: prevalence and predictors. Br JPsychiatry 1997; 171: Wickberg B, Hwang CP. Screening for postnatal depression in a population-based Swedish sample. Acta Psychiatr Scad 1997; 95: Cooper PJ, Campbell EA, Day A, Kennerley H, Bond A. Non-psychotic psychiatric disorder after childbirth. A prospective study of prevalence, incidence, course and nature. Br J Psychiatry 1988; 152: OHara MW, Schlechte JA, Lewis DA, Varner MW. Controlled prospective study of postpartum mood disorders: psychological, environmental, and hormonal variables. J Abnorm Psychol 1991; 100: Cooper PJ, Murray L, Stein A. Postnatal Depression. In: Seva A, editor. European Handbook of Psychiatry and Mental Health. Barcelona, Spain: Anthropos, Davidson J, Robertson E. A follow-up study of post partum illness, Acta Psychiatr Scand 1985; 71: Philipps LH, O Hara MW. Prospective study of postpartum depression: 4 1/2 year follow-up of women and children. JAbnonn Psychol 1991; 100: Cooper PJ, Murray L. Course and recurrence of postnatal depression. Evidence for the specificity of the diagnostic concept. Br JPsychiatry 1995; 166: Cogill SR, Caplan HL, Alexandra H, Robson KM, Kumar R. Impact of maternal postnatal depression on cognitive development of young children. BMJ Clin Res Ed 1986; 292: Murray L, Fion Cowley A, Hooper R, Cooper P. The impact of postnatal depression and associated adversity on early motherinfant interactions and later infant outcome. Child Dev 1996; 67: Sharp D, Hay DF, Pawlby S, Schmucker G, Allen H, Kumar R. The impact of postnatal depression on boys intellectual development. J Child Psychol Psychiatry 1995; 36: Stein A, Gath DH, Bucher J, Bond A, Day A, Cooper PJ. The relationship between post-natal depression and mother-child interaction. Br J Psychiatry 1991; 158: Murray L. The impact of postnatal depression on infant development. J Child Psychol Psychiatry 1992; 33: Brown GW, Davidson S. Social class, psychiatric disorder of mother, and accidents to children. Lancet 1978; 1: Mitchell EA, Thompson JM, Stewart AW et al. Postnatal depression and SIDS: a prospective study. J Paediatr Child Healrh 1992; 28 6UOO1 1): S Woknd S. Mothers depression and their children s attendance at medical facilities. JPsychosom Res 1985; MacArthur C, Lewis M, box E. Health after childbirth. Br J Obstet Gynuecol; 98: Hannah P, Adams D, Lee A, Glover V, Sandler M. Links between early post-partum mood and post-natal depression. Br J Psychiatry 1992; 160: Kendell RE, Rennie D, Clarke JA, Dean C. The social and obstetric correlates of psychiatric admission in the puerperium. Psychol Med 1981; 11: Astbury J, Brown S, Lumley J, Small R. Birth events, birth experiences and social differences in postnatal depression. Aust J Public Health 1994; 18: Hickey AR, Boyce PM, Ellwood D, Moms-Yates AD. Early discharge and risk for postnatal depression. Med JAusf 1997; Tam& R, Murata M, Ohno T. Risk factors for postpartum depression in Japan. Psychiatry Clin Neurosci 1997; 51: Areias MEG, Kumar R, Banos H, Figueiredo E. Correlates of postnatal depression in mothers and fathers. Br J Psychiatry 1996; 169 (Suppl 1): Stein A, Cooper PJ, Campbell EA, Day A, Altham PM. Social adversity and perinatal complications: their relation to postnatal depression. BMJ 1989; 298: Kelly A, Deakin B. Postnatal depression and antenatal morbidity. Br J Psychiatry 1992; 161: Small R, Astbury J, Brown S, Lumley J. Depression after childbirth. Does social context matter? Med JAust 1994; 161: RCOG 2000 BrJ Obstet Gynaecol 107,

8 PO s TPA RTU M D EP RE s s I o N Appleby L, Gregoire A, Platz C, Prince M, Kumar R. Screening women for high risk of postnatal depression. J Psychosom Res 1994; O'Hara MW. Social support, life events, and depression during pregnancy and the puerperium. Arch Gen Psychiatry 1986; 43: Cooper PJ, Murray L, Hooper R, West A. The development and validation of a predictive index for postpartum depression. Psychol Med 1996; Cox JL, Holden JM, Sagovsky R. Detection of postnatal depression. Development of the 10-item Edinburgh Postnatal Depression Scale. Br J Psychiatry 1987; 150: Glaze R, Cox JL. Validation of a computerised version of the 10-item (self-rating) Edinburgh Postnatal Depression Scale. J Affecr Disord 1991; 22: Murray L, Carothers AD. The validation of the Edinburgh Post-natal Depression Scale on a community sample. Br J Psychiatry 1990; 157: Goldberg DP, Gater R, Sartorius N et al. The validity of two versions of the GHQ in the WHO study of mental illness in general health care. Psychol Med 1997; 27: Bech P. Quality of life in psychosomatic research. A psychosomatic model. Psychopathology 1987; Bech P, Loldrup D, Garre K, Rasmussen K, and Erenlund Jensen H. Measurement of the quality of life in assessing therapeutic effects in essential hypertension. Methodological aspects. Ugeskr Laeger 1990; Hedegaard M, Henriksen TB, Sabroe. S, Secher NJ. Psychological distress in pregnancy and preterm delivery. BMJ 1993; 307: Brooke OG, Anderson HR, Bland Jh4, Peacock JL, Stewart CM. Effects on birth weight of smoking, alcohol, caffeine, socioeconomic factors, and psychosocial stress. BMJ 1989; 298: Erdreich LS, Lee ET. Use of relative operating characteristic analysis in epidemiology. Am J Epidemiol1981; 114: Campbell G. Advances in statistical methodology for the evaluation of diagnostic and laboratory tests. Stur Med 1994; Lundh W, Gyllang C. Use of the Edinburgh Postnatal Depression Scale in some Swedish child health care centres. Scund J Caring Sci 1993; 7: Wickberg B, Hwang CP. The Edinburgh Postnatal Depression Scale: validation on a Swedish community sample. Acfa Psychiafr Scand 1996; 94: Carothers AD, Murray L. Estimating psychiatric morbidity by logistic regression: application to post-natal depression in a community sample. Psychol Med 1990; Cox JL, Murray D, Chapman G. A controlled study of the onset, duration and prevalence of postnatal depression. Br J Psychiufry 1993; Brugha TS, Sharp HM, Cooper SA et al. The Leicester 500 Project. Social support and the development of postnatal depressive symptoms, a prospective cohort survey. Psychol Med 1998; 28: Veltema MR. Risk factors and predictive signs of postpartum depression. JAffect Disord. 1998; 49: Boyce PM, Todd AL. Increased risk of postnatal depression after emergency caesarean section. Med JAust 1992; 157: Edwards DR, Porter SA, Stein GS. A pilot study of postnatal depression following caesarean section using two retrospective self-rating instruments.jpsychosomres : Gottlieb SE, Barrett DE. Effects of unanticipated cesarean section on mothers. infants, and their interaction in the first month of life. J Dev Behav Pediafr 1986; 7: Bagedahl-Strindlund M, Monsen Bojesson K. Postnatal depression: a hidden illness. Actu Psychiatr Scand 1998; England SJ, Ballard C, George S. Chronicity in postnatal depression. Eur J Psychiatry; : Accepted 7 June RCOG 2000 Br J Obstet Gynaecol 107,