Table 3

Frequencies, proportions and adjusted ORs for small-for-gestational-age birth, preterm birth and low birth weight by antenatal model of care, British Columbia, 2005–2012

MW
n=4705
GP
n=45 114
OB
n=8053
MW versus GPMW versus OBGP versus OB
n (%)n (%)n (%)OR (95% CI)OR (95% CI)OR (95% CI)
SGA*227/4695 (4.83)3179/45 002 (7.06)689/8025 (8.59)0.71 (0.62 to 0.82)0.59 (0.50 to 0.69)0.83 (0.76 to 0.91)
PTB†207/4702 (4.40)2848/45 028 (6.32)698/8033 (8.69)0.74 (0.63 to 0.86)0.53 (0.45 to 0.62)0.72 (0.65 to 0.79)
LBW‡91/4704 (1.93)1438/45 091 (3.19)393/8046 (4.88)0.66 (0.53 to 0.82)0.43 (0.34 to 0.54)0.65 (0.58 to 0.74)
  • All models adjusted for maternal age, parity, pre-pregnancy body mass index (BMI), infant sex, smoking status and substance use.

  • *Model also adjusted for mental illness and local health area (LHA) socioeconomic rank. ORs based on 4095 births with SGA and 57 722 total births with no missing information for this analysis.

  • †Model also adjusted for medical risk, prior obstetric risk, delivery year, receipt of social assistance, alcohol use, mental illness, neighbourhood socioeconomic position (SEP), LHA socioeconomic rank, LHA income inequality and northern residence. ORs based on 3753 PTB births and 57 763 total births with no missing information for this analysis.

  • ‡Model also adjusted for prior obstetric risk. ORs based on 1922 births with LBW and 57 841 total births with no missing information for this analysis.

  • GP, general practitioner; LBW, low birth weight; MW, midwife; OB, obstetrician; PTB, preterm birth; SGA, small-for-gestational-age.