Skip to main content

Table 3 Frequencies and adjusted odds ratios for preterm birth by antenatal model of care and psychosocial risk characteristics, British Columbia, April 1, 2008-December 31, 2012

From: Improving birth outcomes for women who are substance using or have mental illness: a Canadian cohort study comparing antenatal midwifery and physician models of care for women of low socioeconomic position

Preterm birth by model of care

 

MW n = 3394

GP n = 25,753

OB n = 4746

MW vs. GP

MW vs. OB

GP vs. OB

n(%)

n(%)

n(%)

aOR (95% CI)

aOR (95% CI)

aOR (95% CI)

Mental illnessa

 Yes

56/1011 (5.54)

344/4917 (7.00)

71/545 (13.03)

0.92 (0.68–1.24)

0.49 (0.34–0.72)

*0.54 (0.41–0.71)

 No

98/2383 (4.11)

1257/20,836 (6.03)

352/4201 (8.38)

0.73 (0.59–0.91)

0.51 (0.41–0.65)

0.70 (0.61–0.79)

Substance useb

 Yes

8/152 (5.26)

215/2276 (9.45)

39/182 (21.43)

0.59 (0.29–1.21)

*0.24 (0.11–0.54)

*0.41 (0.28–0.61)

 No

146/3242 (4.50)

1386/23,477 (5.90)

384/4564 (8.41)

0.80 (0.67–0.96)

0.55 (0.45–0.68)

0.69 (0.61–0.79)

Teen mother

 Yes (14–19 yrs.)

9/117 (7.69)

187/2584 (7.24)

21/206 (10.19)

1.09 (0.55–2.19)

0.74 (0.33–1.66)

0.67 (0.42–1.09)

 No (25–29 yrs.)

46/1161 (3.96)

475/7705 (6.16)

100/1371 (7.29)

0.69 (0.50–0.94)

0.56 (0.39–0.80)

0.81 (0.65–1.02)

Social assistancec

 Yes

17/239 (7.11)

299/3617 (8.27)

61/534 (11.42)

0.89 (0.53–1.50)

0.63 (0.36–1.12)

0.71 (0.53–0.96)

 No

137/3155 (4.34)

1302/22,136 (5.88)

362/4212 (8.59)

0.78 (0.64–0.94)

0.51 (0.42–0.63)

0.66 (0.58–0.75)

Neigh. SEPd

 Low/Medium

135/2944 (4.59)

1429/22,915 (6.24)

397/4369 (9.09)

0.80 (0.66–0.96)

0.52 (0.42–0.64)

0.65 (0.58–0.74)

 High

19/450 (4.22)

172/2838 (6.06)

26/377 (6.90)

0.72 (0.44–1.17)

0.63 (0.34–1.17)

0.88 (0.57–1.36)

Mental illness, substance use

 Both

5 or less /95e

95/927 (10.25)

18/76 (23.68)

0.43 (0.15–1.19)

*0.18 (0.06–0.55)

*0.41 (0.23–0.74)

 Neither

94/2325 (4.04)

1134/19,438 (5.83)

331/4090 (8.09)

0.73 (0.59–0.91)

0.52 (0.41–0.66)

0.71 (0.62–0.81)

Mental illness, social assistance

 Both

7/128 (5.47)

117/1195 (9.79)

27/161 (16.77)

0.58 (0.26–1.32)

0.35 (0.14–0.86)

0.60 (0.38–0.96)

 Neither

88/2272 (3.87)

1075/18,414 (5.84)

318/3828 (8.31)

0.70 (0.56–0.88)

0.48 (0.37–0.61)

0.68 (0.59–0.79)

Substance use, social assistance

 Both

5 or less /45e

94/832 (11.30)

22/93 (23.66)

0.78 (0.27–2.27)

0.34 (0.11–1.10)

0.44 (0.26–0.76)

 Neither

133/3047 (4.36)

1178/20,643 (5.71)

345/4118 (8.38)

0.78 (0.65–0.95)

0.53 (0.43–0.65)

0.67 (0.59–0.77)

  1. Abbreviations: MW midwife, GP general practitioner, OB obstetrician, OR odds ratio, CI confidence interval
  2. aMental illness included any of the following diagnoses prior to, or during the current pregnancy: anxiety disorder, depression, postpartum depression, bipolar disorder, other/unknown (including schizophrenic, mood, and psychotic disorders). Aside from mild anxiety or depression, a physician would diagnose mental illness
  3. bSubstance use included any indication in the medical record of heroin/opioids, cocaine, methadone, solvents, marijuana or other/unknown drugs used by the mother at any time during pregnancy, as well as prescription or other drug use identified as a risk by the provider
  4. cSocial assistance recipients received public financial assistance during the year of delivery due to low income
  5. dNeighbourhood low/medium socioeconomic position included women residing in the four lowest income quintiles, depending on residential postal code at delivery
  6. ePercentage suppressed due to small cell size
  7. *Outcomes had statistically significant tests of interaction (p < 0.10) comparing difference of effect across strata (yes vs. no)
  8. Models adjusted for all variables listed except stratifying variables: maternal age, medical risk, obstetric risk, pre-pregnancy BMI, infant sex, receipt of social assistance, smoking status, substance use, mental illness/disorder, neighbourhood SEP, Local Health Area socioeconomic rank, and northern residence
  9. Odds ratios based on 2178 PTB births and 33,893 total births with no missing information for this analysis
Back to article page

BMC Pregnancy and Childbirth

ISSN: 1471-2393

Contact us