Table 2:

Severe maternal morbidity and mortality, by type of delivery*

OutcomeNo. of deliveriesRate per 1000 deliveriesCrude RR (95% CI)Adjusted RR (95% CI)
Uterine rupture
Elective repeat cesarean2431.751.00 (Ref.)1.00 (Ref.)
Attempted VBAC5839.935.72 (4.92 to 6.65)5.24 (4.48 to 6.12)
 Successful VBAC381.300.74 (0.53 to 1.04)0.64 (0.45 to 0.90)
 Failed VBAC54518.510.8 (9.24 to 12.5)9.62 (8.23 to 11.3)
Rupture not including dehiscence
Elective repeat cesarean690.501.00 (Ref.)1.00 (Ref.)
Attempted VBAC1943.306.67 (5.07 to 8.78)6.41 (4.84 to 8.50)
 Successful VBAC150.511.03 (0.59 to 1.80)0.94 (0.54 to 1.66)
 Failed VBAC1796.0812.3 (9.32 to 16.2)11.6 (8.77 to 15.5)
PPH and blood transfusion
Elective repeat cesarean2261.631.00 (Ref.)1.00 (Ref.)
Attempted VBAC2644.502.77 (2.32 to 3.31)2.80 (2.33 to 3.37)
 Successful VBAC1535.233.22 (2.63 to 3.96)3.34 (2.69 to 4.14)
 Failed VBAC1113.772.32 (1.85 to 2.91)2.32 (1.84 to 2.92)
PPH and procedures for bleeding
Elective repeat cesarean2131.531.00 (Ref.)1.00 (Ref.)
Attempted VBAC1252.131.39 (1.11 to 1.73)1.44 (1.15 to 1.82)
 Successful VBAC190.650.42 (0.26 to 0.68)0.44 (0.28 to 0.72)
 Failed VBAC1063.602.35 (1.86 to 2.97)2.33 (1.83 to 2.97)
PPH and hysterectomy
Elective repeat cesarean760.551.00 (Ref.)1.00 (Ref.)
Attempted VBAC320.551.00 (0.66 to 1.51)1.05 (0.68 to 1.62)
 Successful VBAC50.170.31 (0.13 to 0.77)0.33 (0.13 to 0.84)
 Failed VBAC270.921.68 (1.08 to 2.60)1.67 (1.06 to 2.64)
Maternal morbidity and mortality
Elective repeat cesarean7845.651.00 (Ref.)1.00 (Ref.)
Attempted VBAC62910.71.91 (1.72 to 2.12)1.96 (1.76 to 2.19)
 Successful VBAC2097.141.27 (1.09 to 1.48)1.32 (1.13 to 1.55)
 Failed VBAC42014.32.55 (2.26 to 2.87)2.54 (2.25 to 2.87)
Restricted severe morbidity
Elective repeat cesarean6454.651.00 (Ref.)1.00 (Ref.)
Attempted VBAC4227.191.55 (1.37 to 1.76)1.63 (1.43 to 1.85)
 Successful VBAC732.490.54 (0.42 to 0.68)0.57 (0.45 to 0.73)
 Failed VBAC34911.92.57 (2.26 to 2.93)2.58 (2.25 to 2.95)
  • Note: CI = confidence interval, PPH = postpartum hemorrhage, RR = rate ratio, VBAC = vaginal birth after cesarean.

  • * There were 138 836 elective repeat cesarean deliveries, 58 704 attempted VBAC deliveries, 29 261 successful VBAC deliveries and 29 443 failed VBAC deliveries. Our study was restricted to women with a parity of 1 who had a previous cesarean delivery and who delivered a singleton at 37 to 43 weeks gestation in the current pregnancy in Canada (excluding Quebec) from 2003 to 2014.

  • Logistic models included maternal age, diabetes mellitus, hypertension and labour induction.

  • Severe maternal morbidity and mortality included death, acute myocardial infarction, heart failure, pulmonary edema, disseminated intravascular coagulation, cardiac arrest, assisted ventilation, cardiac complications from anesthesia, cardiopulmonary resuscitation, adult respiratory distress syndrome, acute/unspecified renal failure, blood transfusion given PPH, shock procedures to control bleeding given PPH, cesarean hysterectomy given PPH, total hysterectomy open approach given PPH, subtotal hysterectomy open approach given PPH and repair of injury to bladder and urethra.

  • Restricted severe morbidity included the same conditions as for severe maternal morbidity and mortality, except blood transfusion given PPH.