Archives of Women's Mental Health

, Volume 12, Issue 2, pp 105–112

Tailoring screening protocols for perinatal depression: prevalence of high risk across obstetric services in Western Australia

Authors

    • Western Australian Perinatal Mental Health Unit
  • Elizabeth Nathan
    • Women’s and Infant’s Research Foundation Inc.King Edward Memorial Hospital
  • Craig Speelman
    • School of Psychology and Social ScienceEdith Cowan University
  • Delphin Swalm
  • Angela Jacques
    • Women’s and Infant’s Research Foundation Inc.King Edward Memorial Hospital
  • Dorota Doherty
    • School of Women’s and Infants HealthUniversity of Western Australia, King Edward Memorial Hospital
Original Contribution

DOI: 10.1007/s00737-009-0048-7

Cite this article as:
Brooks, J., Nathan, E., Speelman, C. et al. Arch Womens Ment Health (2009) 12: 105. doi:10.1007/s00737-009-0048-7

Abstract

Given what appears to be an ever-increasing list of concerning consequences of perinatal depression, longitudinal studies have much to offer when considering the timing and efficacy of prevention and intervention strategies. The course of depressive symptomatology across the perinatal period at four obstetric services was investigated utilising Western Australian data collected as part of the beyondblue National Postnatal Depression Program. Pregnant women completed one or two Edinburgh Postnatal Depression Scale (EPDS) assessments during pregnancy and a demographic and psychosocial risk factors questionnaire. One or two EPDS assessments were administered within 12 months postpartum. Prevalence of high risk scores across gestational ages ranged from 14% to 5% during pregnancy and 6% to 9% in the postnatal period. For women who were screened twice, the prevalence of high risk scores appeared earlier and decreased with advancing gestation (p = 0.026). The prevalence of postnatal high risk increased after 12 weeks postpartum (p = 0.029). Screening protocols for depressive symptomatology during pregnancy may need to be fine-tuned across individual hospitals, and take into account gestational ages, in order to be most effective. As depressive symptomatology persists postnatally, screening protocols may need to extend beyond 12 weeks postpartum.

Keywords

Perinatal depressionPsychosocial screening

Introduction

There is substantial evidence that maternal distress during pregnancy is associated with adverse cognitive and behavioural consequences for the offspring (see Grace et al. 2003 for review). There are also serious implications of maternal depression during the perinatal period for the mother’s long term mental health (Hammen 2003; Phillips and O’Hara 1991), her partner’s mental health (Harvey and McGrath 1988; Lovestone and Kumar 1993; Morgan et al. 1997) and the parental relationship (Boyce 1994; Morgan et al. 1997).

Given what appears to be an ever-increasing list of concerning consequences of maternal depression across the perinatal period, longitudinal studies have much to offer when considering the timing and efficacy of prevention and intervention strategies. Yet there are relatively few large representative studies which track depressive symptomatology across the perinatal period. Green and Murray (1994) reported results from their longitudinal study where participants completed an Edinburgh Postnatal Depression Scale (EPDS; Cox et al. 1987) in the third trimester of pregnancy and again 6 weeks after the birth. There was a drop in mean EPDS score after birth, a finding consistent with other studies (Evans et al. 2001; Gotlib et al. 1989; Kumar and Robson 1984; Wolkind et al. 1980).

Evans et al. (2001) utilised prospective data gathered from a cohort of 14,000 English women to compare symptom scores from the EPDS at 18 and 32 weeks of pregnancy and 8 weeks and 8 months postpartum. EPDS scores during pregnancy were found to be higher than after the birth, with 11.8% scoring >12 at 18 weeks gestation, 13.6% at 32 weeks, 9.2% at 8 weeks postpartum, and 8.1% at 8 months postpartum. In all, 1.6% scored >12 at all four time points.

Rubertsson et al. (2005) investigated the prevalence of depressive mood in a large Swedish sample of pregnant women (N = 3293). The EPDS was completed at early pregnancy (average 16 weeks, range 7–40 weeks) and then again at 2 months postpartum. Using a cut-off score of ≥12 on the EPDS to indicate depressive mood, the authors reported that 14.7% scored in the antenatal high risk group and 12.3% scored in the postpartum high risk group. Of these, 6.5% were depressed postpartum only and 5.8% depressed in pregnancy and postpartum.

With the literature clearly indicating that women are vulnerable to depression during their pregnancy as well as after birth (Evans et al. 2001; Fergusson et al. 1996; Green and Murray 1994; Josefsson et al. 2001), and that these conditions can have serious effects on the family (Boyce 1994; Grace et al. 2003; Harvey and McGrath 1988; Lovestone and Kumar 1993; Morgan et al. 1997), the need for health care professionals to provide psychological screening, referral and management throughout the perinatal period for obstetric patients is clear. What is not as clear is whether screening protocols can be introduced universally or whether protocols need to be specifically tailored for each obstetric site according to the patient population.

In an attempt to answer this question, the course of depressive symptomatology across the perinatal period was investigated in the current study utilising data collected as part of the beyondblue National Postnatal Depression Program. This Australian program set out to measure the prevalence of depressive symptomatology during pregnancy and after childbirth and to ascertain the optimal time and methods to administer psychosocial screening in a cohort of Australian birthing women (Buist et al. 2002).

The current study focussed on the Western Australian (WA) data for the following reasons: (i) the inclusion of a private hospital, a tertiary public hospital, a family birthing centre and a general public hospital made this cohort unique and so the question of universal versus tailored screening protocols could be investigated; (ii) there was a sub-sample of women with more than one EPDS administered antenatally and postnatally; and (iii) the screening methodology and high postnatal return rate ensured that this is a representative sample (i.e., 80% of the participants completed antenatal and postnatal measures in the WA cohort).

Materials and methods

The study was approved by the Ethics Committee at King Edward Memorial Hospital (KEMH) which also covered the Family Birth Centre (FBC), Osborne Park Hospital (OPH) and Mercy Hospital. These four obstetric sites provide perinatal services to a diverse population of women.

KEMH is the state’s largest public obstetric hospital and the sole tertiary referral centre with close to 6,000 births per annum. These include high risk pregnancies as well as a wide variety of public and private patients.

The Family Birth Centre is a home-like maternity facility situated on the grounds of KEMH, and manages pregnancies and births of women with low obstetric risk. Women wishing to birth at the FBC are screened for obstetric and psychological risk.

OPH is a community general hospital which, like KEMH, caters for the needs of the general population with its public and private facilities, including a social work department.

The fourth obstetric site, Mercy Hospital, caters for private patients only. Subsequently, the patient population is less diverse and of a higher socio-economic status than the other three sites.

Procedure

Women who were able to give informed consent were recruited between July 2002 and December 2004. An EPDS (Cox et al. 1987) was administered along with a demographic and psychosocial risk factors questionnaire (described below).

Universal screening with the EPDS was already in practice at KEMH, FBC and OPH and so completion of the demographic and psychosocial risk factors questionnaire was often all that was required of participants. EPDS data collected on two occasions during pregnancy were available. As patients were being routinely screened for depressive symptomatology at these sites regardless of participation in this study the decline rate was minimal (i.e., <5%). The resulting sample is thus highly representative of these patient populations.

Mercy Hospital was the only hospital not screening routinely with the EPDS and only women who consented to complete an EPDS were recruited. No repeated EPDS screens were performed.

Follow-up occurred within 12-months after delivery with the completion of a repeat EPDS, administered by the participant’s child health nurse as part of their routine care. The EPDS is routinely completed with the child health nurse at each postnatal visit and so is often repeated. If more than one postnatal EPDS was available this was also entered into the study database. A high postnatal return rate was maintained via reminder letters to child health nurses and phone contact with participants as required.

Measures

The EPDS is a ten-item self-report questionnaire. It is the most frequently used screening tool internationally to detect depressive symptomatology in women during both the antenatal and postnatal periods. Women are asked to select one of four responses that most closely describe how they felt over the past 7 days. Each response has a value of between 0 and 3 and scores for the ten items are added together to give a total score. Although a clinical cut-off of >12 on the EPDS is advocated for reducing false positives in perinatal screening (Buist et al. 2002), and is widely accepted for postnatal use, a variety of cut-offs continue to be used in the antenatal period, from EPDS >10 to EPDS > 15 (Bennet et al. 2004). Antenatal EPDS scores from 0–11 were classified as low risk and 12–30 as high risk in accordance with the screening criteria and referral guidelines administered at KEMH and applied in the research of Rubertsson et al. (2005). Postnatal EPDS scores from 0–12 were considered low risk and from 13–30 were considered high risk as originally recommended by Cox et al. (1987) and maintained by the beyondblue National Postnatal Depression Program (Buist et al. 2005).

The demographic and psychosocial risk factors questionnaire was purpose designed for the national program and included questions on country of birth, language spoken at home, socioeconomic status, occupation, highest level of education completed, past history of mental illness, current mental illnesses, major life events in the past 12 months, daily hassles, availability of emotional/practical supports, relationship with mother and partner, baby gender desired, and past history of abuse (sexual, physical and emotional).

Data analysis

Descriptive statistics included medians and inter-quartile ranges (IQR) for continuous data. Frequency distributions were used to summarise categorical data. Univariate analysis was performed using Wilcoxon Rank Sum Test, Kruskal-Wallis and Chi-square or Fisher Exact Test for continuous and categorical data, as appropriate. Binary outcomes representing a change in total score between first and second EPDS were analysed. Changes in EPDS scores during pregnancy (decrease) and postpartum (increase) were investigated using logistic regression analysis on a sample of women who had two EPDS scores. Covariates considered were first EPDS risk (high v. low) gestational age/baby’s age at first EPDS and the time interval between assessments. All p-values were two-tailed and p-values <0.05 were considered statistically significant. SPSS 15.0 statistical software (SPSS Inc, Chicago IL) was used to analyse the data.

Results

Over a period of two and a half years, 4,838 women participated in the study. KEMH recruited 2,776 women, and an additional 255 women at the Family Birth Centre (FBC) at KEMH. OPH recruited 1,362 women, and 445 women were recruited from Mercy Private Hospital. The median gestational age at time of recruitment was 26 weeks (IQR 19–35; range 10–42). Differences in median gestational ages were observed between the recruiting centres (p < 0.001). Women attending OPH and Mercy Hospitals were of a later gestational age, medians 33 weeks and 35 weeks respectively, than women recruited through KEMH and FBC, median gestational ages 20 weeks and 22 weeks respectively.

Demographic and pregnancy data

There were significant differences between the recruiting hospitals for many of the demographic, obstetric and psychosocial factors (Tables 1 and 2). Depression during pregnancy was more common among women recruited at KEMH (15%) and OPH (12%), compared with Mercy (4%) and FBC (7%). Twenty-seven percent of women reported they had felt miserable or depressed for 2 weeks or more prior to pregnancy, and 55% of these women sought professional help. A medical diagnosis of major depression had been given for 4% of women, minor depression (14%) and anxiety (7%). A diagnosis of major depression prior to the current pregnancy was reported more often among women attending KEMH (17%) and OPH (13%), compared with Mercy (5%) and FBC (3%).
Table 1

Demographic characteristics stratified by hospital

Demographics

FBC (n = 255)

KEMH (n = 2776)

OPH (n = 1362)

MERCY (n = 445)

All (n = 4838)

p-value

Maternal agea

31 (25–39)

28 (25–40)

28 (24–40)

31 (21–31)

29 (24–40)

<.001

Marital status:

Never married

25 (10%)

498 (18%)

236 (18%)

8 (2%)

767 (16%)

<.001

No longer married

4 (2%)

123 (5%)

61 (5%)

1 (0.2%)

189 (4%)

 

Married/defacto

225 (89%)

2,130 (77%)

1,043 (78%)

435 (98%)

3,833 (80%)

 

English home language

244 (96%)

2,608 (94%)

1,289 (95%)

439 (99%)

4,580 (95%)

<.001

Aboriginal/TSI

1 (0.4%)

168 (6%)

37 (3%)

3 (1%)

209 (4%)

<.001

Education level:

No finish high school

10 (4%)

350 (13%)

210 (15%)

7 (2%)

577 (12%)

<.001

High school

102 (40%)

1,506 (54%)

812 (60%)

237 (53%)

2,657 (55%)

 

Tertiary

137 (54%)

723 (26%)

249 (18%)

183 (41%)

1,292 (27%)

 

Other education

6 (2%)

197 (7%)

91 (7%)

18 (4%)

312 (6%)

 

Gravidity:

1st pregnancy

106 (42%)

922 (33%)

517 (38%)

230 (52%)

1,775(37%)

<.001

2nd or 3rd pregnancy

117 (46%)

1,275(46%)

598 (44%)

177 (40%)

2,167(45%)

 

4th or more pregnancy

31 (12%)

560 (20%)

231 (17%)

35 (8%)

857 (18%)

 

Number of children:

0 children

140 (55%)

1,185 (43%)

616 (46%)

285 (65%)

2,226 (46%)

<.001

1–2 children

103 (40%)

1,321 (48%)

597 (44%)

148 (34%)

2,169 (45%)

 

3 or more children

12 (5%)

257 (9%)

134 (10%)

9 (2%)

412 (9%)

 

Miserable/depressed past

(2 weeks or more)

76 (30%)

782 (28%)

307 (23%)

103 (23%)

1,268 (27%)

0.001

Diagnosis of depression prior to this pregnancy:

Minor

33 (13%)

411 (15%)

199 (15%)

46 (10%)

689 (14%)

0.079

Major

2 (1%)

157 (6%)

47 (4%)

7 (2%)

213 (4%)

<.001

Data represented as number and frequency (%), except where otherwise indicated

aindicates median (IQR)

Table 2

Obstetric and psychological profile stratified by hospital

 

FBC (n = 255)

KEMH (n = 2776)

OPH (n = 1362)

MERCY (n = 445)

All (n = 4838)

p-value

Multiple pregnancy

-

104 (4%)

12 (1%)

6 (1%)

122 (3%)

<.001

Pregnancy problems:

No obstetric issues

133 (52%)

1,174(42%)

630 (46%)

236 (53%)

2,173(45%)

<.001

Varicose veins/ haemorrhoids

55 (22%)

479 (17%)

221 (16%)

83 (19%)

838 (17%)

<.001

Excessive vomiting

27 (11%)

379 (14%)

167 (12%)

36 (8%)

609 (13%)

<.001

Bladder/kidney infection

9 (4%)

139 (5%)

66 (5%)

12 (3%)

226 (5%)

<.001

Diabetes

5 (2%)

190 (7%)

47 (4%)

22 (5%)

264 (6%)

<.001

Threatened miscarriage

22 (9%)

316 (11%)

102 (8%)

52 (12%)

492 (10%)

<.001

High blood pressure

4 (2%)

228 (8%)

124 (9%)

7 (2%)

363 (8%)

<.001

Alcohol intake (per day):

None

96 (38%)

1,674(62%)

790 (59%)

204 (47%)

2,764(58%)

<.001

< 1 drink

133 (52%)

818 (30%)

419 (32%)

199 (45%)

1,569(33%)

 

1 drink

16 (6%)

102 (4%)

69 (5%)

28 (6%)

215 (5%)

 

> 1 drink

9 (4%)

114 (4%)

51 (4%)

7 (2%)

181 (4%)

 

Emotional problems:

Eating disorder

-

44 (2%)

12 (1%)

1 (-)

57 (1%)

<.001

Difficulty accepting pregnancy

8 (3%)

123 (4%)

53 (4%)

7 (2%)

191 (4%)

0.032

Counselling/therapy

9 (4%)

221 (8%)

96 (7%)

8 (2%)

334 (7%)

<.001

Antidepressants

2 (1%)

114 (4%)

49 (4%)

7 (2%)

172 (4%)

0.004

Other therapies

4 (2%)

49 (2%)

21 (2%)

7 (2%)

81 (2%)

<.001

Data represented as number and frequency (%)

Women were also asked about any major distressing life events they had experienced in the past 12 months. Most common events included moving house (29%), financial difficulties (24%), the death of someone close (12%), unemployment (8%), separation (6%), and physical illness (5%). Frequently reported personality characteristics included a tendency to worry unnecessarily (50%), the need for order in life (30%), being guilt prone (28%) and feeling unable to achieve (12%).

There were 969 women (20%) who reported anxiety and/or depression during their current pregnancy. Of these women, 30% had received psychological therapy, 16% received medication, and 6% had sought other methods of treatment for their psychiatric or psychological condition.

Antenatal EPDS

Overall, the median antenatal EPDS score was 5 (IQR 2–8; range 0–28). Ninety percent of women scored 0–11 on the antenatal EPDS and were considered at low risk of depression, and 10% scored 12–30 and were considered high risk. Of the women with scores ≥12, 26% remained at high risk (>12) in the postnatal assessment.

Total EPDS scores were significantly different between the recruiting centres (p < 0.001). Mercy Hospital and FBC had a lower percentage of women in the high risk EPDS group than the public hospitals, with only 2–3% women classified as high risk in each of the private centres compared with 9–12% at KEMH and OPH.

Prevalence of high risk varied according to gestational age (Fig. 1). Of the women at ≤16 weeks gestational age (n = 492), 14% were identified as high risk. Between 16 weeks to 38 weeks (n = 3961), 10% were high risk; and at 38+ weeks (n = 253) 5% were high risk.
https://static-content.springer.com/image/art%3A10.1007%2Fs00737-009-0048-7/MediaObjects/737_2009_48_Fig1_HTML.gif
Fig. 1

Percentage of high risk EPDS scores for the perinatal period

During the antenatal period 989 women completed a second EPDS, of which 49% were from KEMH, 44% OPH and 7% FBC. Overall, the median second EPDS score was 4 (IQR 2–7; range 0–28). Demographic, psychosocial and obstetric characteristics of women screened once in pregnancy did not differ from those of women with repeated EPDSs (Table 3). A higher proportion of women with diabetes had two EPDSs due to more frequent antenatal visits. Logistic regression analysis showed a significant interaction between high first EPDS score and duration of time until the second EPDS was collected (Table 4, Fig. 2). Women at high risk on their first EPDS were significantly more likely to show a decrease in EPDS score with advancing gestation (p = 0.026), irrespective of gestational age at first EPDS (p = 0.986).
https://static-content.springer.com/image/art%3A10.1007%2Fs00737-009-0048-7/MediaObjects/737_2009_48_Fig2_HTML.gif
Fig. 2

Likelihood that an EPDS measured for the second time later in gestation will have a lower total score. Data is stratified by high and low risk groups

Table 3

Demographic and psychosocial characteristics of women who completed a single EPDS compared with repeated EPDS assessments

Demographic & psychosocial characteristics

Single antenatal EPDS

Repeat antenatal EPDS

p-value

Single postnatal EPDS

Repeat postnatal EPDS

p-value

Maternal Agea

29 (24–32)

29 (24–32)

0.861

29 (25–33)

29 (24–33)

0.863

Marital status:

Never married

586 (16%)

168 (17%)

 

505 (15%)

72 (15%)

 

No longer married

148 (4%)

37 (4%)

0.621

122 (4%)

14 (3%)

0.775

Married/defacto

2,948 (80%)

774 (79%)

 

2,727 (81%)

381 (82%)

 

English Language

3,519 (95%)

939 (95%)

0.665

3,204 (95%)

451 (96%)

0.160

Aboriginal/TSI

164 (4%)

35 (4%)

0.227

107 (3%)

9 (2%)

0.140

Education level:

Not finished school

456 (12%)

112 (11%)

 

386 (11%)

39 (8%)

 

High school

2,036 (55%)

550 (56%)

0.878

1,865 (55%)

263 (56%)

0.237

Tertiary

986 (27%)

262 (27%)

 

921 (27%)

137 (29%)

 

Other education

242 (7%)

65 (7%)

 

214 (6%)

30 (6%)

 

Number of children:

0 children

1,721 (47%)

446 (45%)

 

1,596 (48%)

206 (44%)

 

1–2 children

1,664 (45%)

446 (45%)

0.685

1,493 (44%)

231 (49%)

0.109

3 or more children

311 (8%)

90 (9%)

 

273 (8%)

31 (7%)

 

History of Depression

972 (27%)

267 (27%)

0.580

889 (27%)

129 (28%)

0.567

Gravidity:

1st pregnancy

1,354 (37%)

373 (38%)

 

1,279 (38%)

159 (34%)

 

2nd or 3rd pregnancy

1,686 (46%)

426 (43%)

0.343

1,502 (45%)

228 (49%)

0.190

4th or more pregnancy

646 (18%)

186 (19%)

 

577 (17%)

79 (17%)

 

Multiple Birth

100 (3%)

21 (2%)

0.318

89 (3%)

10 (2%)

0.524

Pregnancy problemsb

2,047 (55%)

547 (55%)

0.881

1,846 (55%)

259 (55%)

0.779

Diabetesc

182 (5%)

72 (7%)

0.003

176 (5%)

21 (5%)

0.506

Diagnosis of Psychological Condition

971 (26%)

244 (25%)

0.358

849 (25%)

128 (27%)

0.302

Depression this pregnancy

466 (13%)

121 (12%)

0.802

390 (12%)

57 (12%)

0.689

Anxiety this pregnancy

476 (13%)

123 (12%)

0.761

432 (13%)

61 (13%)

0.882

Difficulty accepting pregnancy

143 (4%)

44 (4%)

0.387

128 (4%)

13 (3%)

0.275

Data represented as number and frequency (%), unless otherwise indicated

aindicates median (IQR),

bpregnancy problems included excessive vomiting, high blood pressure, varicose veins, diabetes, bladder/kidney infection, bleeding/threatened miscarriage,

cwomen with diabetes were more likely to complete a second EPDS due to their more frequent visits to the antenatal clinic

Table 4

Likelihood that an EPDS measured for the second time later in gestation will have lower total scores, stratified by high and low risk groups

Time interval

High risk

Low risk

(weeks)

OR

Probability

Probability

4

1.86

0.61

0.45

8

2.71

0.68

0.44

12

3.95

0.75

0.43

16

5.75

0.81

0.42

20

8.37

0.85

0.41

24

12.19

0.89

0.40

Example: a woman completes her first EPDS at 16 weeks which classifies her as high risk for depression. She completes her second EPDS 4 weeks later. The probability her EPDS score will decrease over this time interval is 61% (OR 1.86). The same woman instead completes her second EPDS at term. The probability she will have a lower second EPDS score after this time interval is 89% (OR 12.19)

OR odds ratio

Calculations based on logistic equation:

\(OR\left( {high\,vs\,low} \right) = {{\exp \left( {0.094 + 0.084 * time\,interval} \right)} \mathord{\left/ {\vphantom {{\exp \left( {0.094 + 0.084 * time\,interval} \right)} {\exp \left( { - 0.151 - 0.01 * time\,interval} \right)}}} \right. \kern-\nulldelimiterspace} {\exp \left( { - 0.151 - 0.01 * time\,interval} \right)}}\)

\(Probability\,\left( {high\,risk} \right)\, = {1 \mathord{\left/ {\vphantom {1 {\left( {1 + \exp \left( { - \left( {0.094 + 0.084 * time\,interval} \right)} \right)} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {1 + \exp \left( { - \left( {0.094 + 0.084 * time\,interval} \right)} \right)} \right)}}\)

\(Probability\,\left( {low\,risk} \right) = {1 \mathord{\left/ {\vphantom {1 {\left( {1 + \exp \left( { - \left( {0.151 - 0.010 * time\,interval} \right)} \right)} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {1 + \exp \left( { - \left( {0.151 - 0.010 * time\,interval} \right)} \right)} \right)}}\)

Postnatal EPDS

The median postnatal EPDS score was significantly less (median 4, IQR 2–7, range 0–28) than the overall antenatal score (median 5, IQR 2–8; range 0–28; p < 0.001). Of the 3,853 women who completed the EPDS postnatally, 6% were considered at high risk of postnatal depression. KEMH had a higher percentage of women in the high risk group (7%), while the other hospitals ranged from 3% to 5%.

The median infant age was 7 weeks (IQR 6–11; range 0–48): low risk women median 7 weeks (IQR 6–11; range 0–48) and high risk women median 8 weeks (IQR 6–15; range 1–38). The percentage of women in the high risk category, stratified by infant’s age, is shown in Fig. 1. Of the 3,853 women who completed a postnatal EPDS, 778 (20%) had babies up to 6 weeks of age, 2,63 (59%) had babies from 6 weeks to 12 weeks of age and 812 (21%) had babies over 12 weeks of age.

A second postnatal EPDS was obtained on 469 women (12%) as part of their routine care with their child health nurse. Overall, the median second postnatal EPDS score for these women was 3 (IQR 1–7; range 0–27). Demographic, psychosocial and obstetric characteristics of women screened once postpartum did not differ from those of women with repeated EPDS’s (Table 3). There was an increasing trend in postnatal risk scores as infant age increased. Logistic regression analysis indicated that women were 55% more likely to have an increased EPDS score when their second EPDS was completed after 12 weeks compared with women who completed their second EPDS up to 12 weeks postpartum (OR 1.55 95%CI 1.04–2.29, p = 0.029). Infant age at first EPDS (p = 0.092), high risk at first EPDS (p = 0.084), antenatal high risk (p = 0.552), history of depression prior to pregnancy (p = 0.559) and previous diagnosis of depression (p = 0.127) were not significantly associated with an increased EPDS score.

Discussion and conclusions

Prevalence of high risk for both antenatal and postnatal depression were lower than expected, based upon the results of Rubertsson et al. (2005) and Evans et al. (2001). Using a similar sample size and the same antenatal cut-off score on the EPDS (the postnatal cut-off was 1 lower than used in the current study), Rubertsson et al. (2005) reported an antenatal prevalence of 14.7% and postnatal prevalence of 12.3%, compared to the current 10% and 6% respectively.

We can postulate three reasons for this difference. Firstly, self-selection bias has been reduced in the current study due to well-established and universal antenatal and postnatal EPDS screening and referral protocols in three of the four recruitment sites prior to the beginning of this study. In previous studies, where screening was not being conducted prior to or outside the study protocol, women wanting the additional attention/support afforded via study participation may have chosen (i.e., self-selected) to participate, inflating the level of depressive symptomatology in the sample.

Secondly, the inclusion of a private hospital and family birth centre makes this sample unique. That is, significantly lower antenatal EPDS scores were observed at these sites and reduced the overall scores considerably.

In contrast to the results of Evans et al. (2001) who also utilised a large cohort and prospective longitudinal design, a decreasing trend in depressive symptomatology as pregnancy progressed was observed and EPDS scores in the postnatal period increased significantly after 12 weeks. This contrast in postnatal results may be explained by the second EPDS in the Evans et al. study being administered at 8 months postpartum as opposed to ≥13 weeks in the current study. This finding also contrasts with research suggesting that postnatal depression decreases in the 10–14 week postnatal time-frame (Horowitz and Goodman 2004). Nevertheless, median EPDS scores were found to be lower in the postnatal period compared to the antenatal period, a finding consistent with previous studies (Evans et al. 2001; Gotlib et al. 1989; Kumar and Robson 1984; Wolkind et al. 1980).

Prevalence of antenatal high risk scores differed greatly across the hospital sites. Depression during pregnancy (as indicated by an EPDS ≥12) was more common among women recruited at KEMH (the tertiary hospital) and OPH (the general public hospital) than at Mercy (the private hospital) and the Family Birth Centre.

As the only tertiary obstetric institution in WA, the higher prevalence rates of perinatal depression were not unexpected for women attending KEMH. The higher prevalence rates at OPH, a community general hospital, were also not unexpected when compared to the Family Birth Centre. The Family Birth Centre had a much lower prevalence of likely depression, owing to the strict admission criteria required for women to use this facility. Most interestingly, Mercy Hospital had the lowest prevalence of high antenatal EPDS scores.

With a decreasing trend in antenatal scores as pregnancy progressed, the lower scores at Mercy may in part be explained by the later screening protocol in place at this hospital. Nevertheless, stigma has also been postulated as a factor with considerable influence for women receiving private care when self-report measures are used (Bishop 2002) and as such, additional screening methods and better rapport building may be required in private hospitals in order to reduce fear of judgement.

Interestingly, the prevalence of depressive symptomatology did not vary significantly between hospitals in the postnatal period which may suggest pregnancy-related problems (i.e., whether the pregnancy was considered high or low risk and thus where the woman delivered) accounted for some distress in the antenatal period.

Despite 20% of women suffering from anxiety or depression during their current pregnancy, only 30% of these women received any treatment for their psychiatric or psychological condition. Yet of the women who were considered high risk antenatally, only 26% remained at high risk in the postnatal assessment, a result similar to that of Watson et al. (1984). This result suggests that many of the stressors responsible for symptomatology during pregnancy naturally abate following birth but that a new set of stressors may develop, perhaps helping to explain the failure of antenatal models to predict PND (Austin and Lumley 2003).

So, returning to the initial question—can perinatal screening protocols be introduced universally or do protocols need to be tailored to the patient population of each obstetric site? These findings suggest that screening protocols for depressive symptomatology during pregnancy may need to be fine-tuned across individual hospitals, and take into account gestational ages, in order to be most effective. For example, antenatal screening with the EPDS at tertiary obstetric sites may be most beneficial if conducted as early as feasible and repeated before delivery, and a more personal approach (i.e., semi-structured interview style) adopted at private hospitals where risk is reduced but stigma may prevent women completing a self-report scale honestly.

In addition, depressive symptomatology persists postnatally, so screening protocols may need to extend beyond 13 weeks postpartum, regardless of delivery hospital.

Acknowledgements

The authors would like to acknowledge beyondblue: the national depression initiative for funding the current research project and the Women and Infants Research Foundation for their continued support. We acknowledge the guidance and inspiration provided by the late Dr Sherryl Pope who launched the beyondblue PND Program in Western Australia. We also acknowledge the valuable contribution of the Research Midwifes and postgraduate students who recruited participants: Colleen Ball, Jocelyn Bristol, Sandy Maclean, Monica Howard, Debbie Lien, and Flavia Bises; and James Humphreys for his management of the data.

Copyright information

© Springer-Verlag 2009