Table 1 Characteristics of the study participants by depression status at 6 weeks postpartum (EPDSa score 0–11 vs. 12–30) (n = 4313).

From: Predicting women with depressive symptoms postpartum with machine learning methods

Characteristics

Missing values

EPDSa at 6 weeks postpartum

po

0–11 (n = 3736)

12–30 (n = 577)

N (%) or median (IQRb)

Age (years)

3

31 (6)

31 (6)

0.247

BMI (kg/m2) before pregnancy

162

22.8 (4.4)

23.3 (5.5)

0.001

Height at gestational week 17 (cm)

151

168 (9)

167 (8)

0.305

University level education (vs. less)

268

2734 (78%)

387 (72%)

0.001

Employment

264

  

< 0.001

 Full-time work

 

2291 (65%)

310 (57%)

 

 Part-time work

 

696 (20%)

102 (19%)

 

 Studying

 

242 (7%)

49 (9%)

 

 Maternity leave

 

110 (3%)

15 (3%)

 

 Sick-leave

 

89 (3%)

26 (5%)

 

 Unemployed

 

78 (2%)

41 (7%)

 

Marital status (single vs. married/cohabiting)

9

55 (1.5%)

16 (2.8%)

0.022

Country of origin (scandinavia vs. other)

184

3311 (93%)

499 (91%)

0.193

Depression historyc

185

959 (27%)

296 (54%)

< 0.001

Contact with psychiatrist (self-reported)d

250

285 (8%)

98 (18%)

< 0.001

Contact with psychologist (self-reported)d

250

1190 (34%)

299 (55%)

< 0.001

Hypomanic episodes (1 or more vs. none)d

270

141 (4.0%)

50 (9.3%)

< 0.001

Premenstrual syndrome history (based on the ICD and ACOG criteria)d

303

169 (4.9%)

79 (15%)

< 0.001

History of pregnancy loss

2072

21 (1.1%)

5 (1.6%)

0.477

Parity

303

  

0.072

 0

 

1934 (55%)

309 (60%)

 

 1

 

1082 (31%)

154 (30%)

 

 2 or more

 

477 (14%)

54 (10%)

 

Smoking, ever

175

1157 (32%)

197 (36%)

0.096

Snuff, before pregnancy

402

251 (7.4%)

40 (7.6%)

0.846

Sleep before pregnancy (hours per day)

179

  

0.005

 < 6

 

124 (3%)

32 (6%)

 

 6–8

 

29 27 (82%)

421 (77%)

 

 > 8

 

534 (15%)

96 (17%)

 

Migrained

295

584 (17%)

120 (22%)

0.002

Irritable bowel syndromed

295

127 (3.7%)

32 (5.9%)

0.011

Alcohol problemsd

295

5 (0.1%)

5 (0.9%)

0.001

Allergiesd

295

764 (22%)

119 (22%)

0.951

Endocrine problemsd

295

124 (3.6%)

25 (4.6%)

0.220

Hypertensiond

295

55 (1.6%)

14 (2.6%)

0.091

Pain problemsd

295

137 (3.9%)

43 (8.0%)

< 0.001

Intimate partner violenced

275

362 (10%)

107 (20%)

< 0.001

Pregnancy-related variables

Planned pregnancy

288

481 (14%)

121 (22%)

< 0.001

Assisted reproductive technology treatment

424

369 (11%)

46 (8.7%)

0.120

Several ultrasounds during gestation

298

2241 (65%)

371 (69%)

0.048

Fear of childbirth

254

  

< 0.001

 No fear

 

2774 (79%)

336 (62%)

 

 Fear of caesarean section

 

339 (9.6%)

73 (14%)

 

 Fear of vaginal delivery

 

208 (5.8%)

61 (11%)

 

 Severe fear

 

200 (5.6%)

68 (13%)

 

Visit at fear of childbirth support unit

250

77 (2.2%)

19 (3.5%)

0.061

Negative delivery expectations

305

504 (15%)

131 (25%)

< 0.001

Pregnancy nausea

281

  

< 0.001

 No

 

705 (20%)

74 (14%)

 

 Yes, without medication

 

2313 (66%)

363 (67%)

 

 Yes, with medication

 

476 (14%)

101 (19%)

 

SSRIf use during pregnancy

368

132 (3.9%)

39 (7.5%)

0.001

Anxiety during pregnancyg

237

1032 (29%)

387 (72%)

< 0.001

Depression during pregnancyh

162

472 (13%)

298 (53%)

< 0.001

Sleep during pregnancy (hours per day)i

266

  

< 0.001

 < 6

 

322 (9%)

98 (18%)

 

 6–8

 

2340 (67%)

332 (61%)

 

 > 8

 

843 (24%)

112 (21%)

 

Self-reported pregnancy complications (any)j

354

1471 (42.7%)

215 (42.0%)

0.771

Gestational diabetesj

136

35 (1.0%)

19 (3.5%)

< 0.001

Preeclampsiaj

136

117 (3.2%)

23 (4.2%)

0.242

Anaemiaj

354

103 (3.0%)

21 (4.1%)

0.177

Hypertensionj

347

165 (4.8%)

41 (8.0%)

0.002

Symphysiolysisj

683

1212 (39%)

228 (47%)

< 0.001

Pregnancy length (days)

194

280 (13)

280 (14)

0.103

Childbirth-related variables

Delivery month

1

6 (6)

6 (6)

0.386

Induction

301

651 (18.6%)

100 (19.3%)

0.697

Mode of delivery

0

  

0.107

 Spontaneous vaginal

 

2795 (75%)

402 (70%)

 

 Elective caesarean section

 

271 (7%)

47 (8%)

 

 Acute caesarean section

 

320 (9%)

64 (11%)

 

 Emergency caesarean section

 

33 (1%)

7 (1%)

 

 Instrumental delivery

 

317 (8%)

57 (10%)

 

Postpartum hemorrhage (≥ 1000 ml vs. < 1000 ml)

301

221 (6.3%)

46 (8.9%)

0.028

Epidural anaesthesia

286

1306 (37%)

238 (46%)

< 0.001

Laceration (Grade III/IV vs. I/II)

146

103 (2.8%)

14 (2.6%)

0.712

Infant-related variables

Gender (female)

171

1733 (48%)

269 (50%)

0.458

Birthweight (kg)

204

3.6 (0.65)

3.6 (0.70)

0.201

Birth length (cm)

219

51 (2.5)

51 (3.0)

0.242

Head circumference (cm)

1184

35 (2.0)

35 (2.0)

0.672

Apgar score (1st min)

222

  

0.027

 0–3

 

26 (1%)

6 (1%)

 

 4–6

 

111 (3%)

28 (5%)

 

 7–10

 

3418 (96%)

502 (94%)

 

Umbilical artery base deficit

991

− 2.9 (4.2)

− 2.6 (4.6)

0.250

Umbilical artery pH

949

7.3 (0.10)

7.3 (0.11)

0.519

Newborn admission to neonatal unit

286

300 (8.6%)

69 (13%)

< 0.001

Postpartum variables

Negative delivery experience

411

217 (6.4%)

85 (17%)

< 0.001

Partner helpful with infant

40

  

< 0.001

 Yes, a lot

 

2334 (63%)

300 (53%)

 

 Yes, a little

 

1281 (35%)

235 (41%)

 

 No

 

87 (2%)

36 (6%)

 

Breastfeeding

11

  

< 0.001

 Yes, exclusive

 

2918 (78%)

354 (62%)

 

 Yes, non-exclusive

 

576 (16%)

146 (25%)

 

 No

 

233 (6%)

75 (13%)

 

Stressful life events past 6 months (3–30 vs. 0–2)

13

395 (11%)

129 (22%)

< 0.001

Psychometric scales

ASQ [pregnancy week 32]k

 Distance

2658

2.8 (1.1)

3.4 (1.4)

< 0.001

 Insecure and repudiation connection

2658

2.1 (0.86)

2.3 (1.0)

< 0.001

 Trust

2658

4.8 (1.0)

4.3 (1.3)

< 0.001

 Consents

2658

2.9 (1.3)

3.7 (1.4)

< 0.001

 Relation

2658

3.0 (1.0)

3.5 (1.1)

< 0.001

SOC (total score) [pregnancy week 32]l

2095

154 (28)

131 (31)

< 0.001

LITE (number of events) [12 months postpartum]m

1696

3.0 (3.0)

4.0 (4.0)

< 0.001

Resilience Scale-14 [pregnancy week 32]

1982

81 (15)

72 (24)

< 0.001

Beck anxiety inventory (moderate/severe vs. minimal/mild) [pregnancy week 32]

2015

299 (15%)

162 (50%)

< 0.001

SSP-Neuroticism score [pregnancy week 32]n

3230

328 (66)

387 (64)

< 0.001

SSP-Aggressiveness score [pregnancy week 32]

3236

195 (26)

203 (26)

0.001

SSP-Sensation Seeking score [pregnancy week 32]

3224

94 (19)

95 (17)

0.258

  1. Bold values indicate p < 0.05.
  2. aEdinburgh Postnatal Depression Scale.
  3. bInterquartile range.
  4. cSelf-reported and/or diagnosed by psychiatrist.
  5. dPregnancy week 17, self-reported.
  6. eEPDS ≥ 12 at pregnancy week 17 or 32 or at delivery.
  7. fSelective serotonin reuptake inhibitors.
  8. gBased on either the Beck Anxiety Inventory, the State Trait Anxiety Inventory (STAI) or the anxiety subscale of the EPDS (EPDS 3A, items 3–5).
  9. hEPDS ≥ 12 at pregnancy week 17, 32 or 38.
  10. iPregnancy week 32.
  11. jSelf-reported, pregnancy week 32.
  12. kAttachment Style Questionnaire.
  13. lSense of Coherence Questionnaire-29.
  14. mLifetime Instances of Traumatic Events.
  15. nSwedish Universities scales of Personality.
  16. oBased on the Mann–Whitney test for continuous variables and the Pearson Chi-square test for the categorical variables.
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