In the original TBS, 2,804 women were included. A total of 1,347 (48.0%) women required delivery prior to the onset of spontaneous labor: 779 (57.8%) in the planned CS arm and 568 (42.2%) in the planned VD arm. Overall, 31 women (3.9%) in the planned CS arm and 190 women (33.4%) in the planned VD arm crossed over to the other group following a discussion regarding the need for delivery.
Of the 1,347 women who needed a delivery, 409 (30.4%) had an IOL and 938 (69.6%) PrlCS (Figure 1). The groups were significantly different with regards to maternal age, parity, previous cesarean section status, antenatal corticosteroids use, estimated fetal weight of the second twin, and gestational age and presentation at delivery (Table 1). In the IOL group, 155 women (37.9%) had an intrapartum CS for both twins, and 14 (3.4%) had a CS for the second twin.
The rate of the primary neonatal outcome was comparable between the PrlCS and IOL groups (1.65% vs. 1.97%; p=0.61; OR 0.83; 95% CI 0.43-1.62). The rates of the individual components of the neonatal composite outcome were similar between the groups as well (Table 2).
The maternal composite outcome was significantly lower in the PrlCS group: 7.25% vs. 11.25% (p=0.01; OR 0.61; 95% CI 0.41-0.91), and this difference stemmed primarily from the differences in hemorrhagic morbidity. Compared with women in the IOL group, women in the PrlCS group had significantly lower rates of hemorrhage (6.19% vs. 9.56%; p=0.02; OR 0.62; 95% CI 0.40-0.94), and required less postpartum uterine dilatation and curettage (0.32% vs. 1.47%; p=0.03; OR 0.21; 95% CI 0.05-0.86). The rate of severe perineal injury (3rd or 4th degree) in the IOL group was 0.98%. There were no significant differences between the two groups in respect to other individual maternal outcomes (Table 3).
We also performed a sub-analysis of women who had IOL or PrlCS for “advanced gestational age” in a twin pregnancy. The characteristics of these women were similar in terms of age, parity, gestational age at delivery, estimated fetal weight of each twin and antenatal steroid use. While the rate of the composite primary neonatal outcome was similar between the two sub-groups, maternal outcome was found to be significantly lower with PrlCS in comparison with IOL (0% vs. 9.41%; p=0.03; OR 0.15; 95% CI 0-0.7). Again, this was mainly due to differences in the rates of hemorrhagic episodes. There were no significant differences between the two sub-groups with respect to individual neonatal or maternal outcomes (Table 4 & Table 5).
Table 1. Characteristics of women who underwent pre-labor cesarean section (PrlCS ) or induction of labor (IOL).
Characteristic n (%)
|
PrlCS
(n=938)
|
IOL
(n=409)
|
P
|
Maternal age (y) mean±SD
≥30
|
29.7 ±6.1
445 (47.4)
|
30.5±6.1
212 (51.8)
|
0.01
0.14
|
Parity ≥1
|
560 (59.7)
|
208 (50.9)
|
0.003
|
Previous cesarean section
|
95 (10.1)
|
18 (4.4)
|
0.0005
|
Estimated fetal weight
First twin (g) mean±SD
Second twin (g) mean±SD
|
2245±430
2225±422
|
2284±420
2291±432
|
0.12
0.008
|
Mode of delivery
Vaginal for both
Cesarean for both
Vaginal/cesarean
|
0
938 (100.00)
0
|
240 (58.7)
155 (37.9)
14 (3.4)
|
< 0.0001
|
Presentation at delivery
Cephalic/Cephalic
Cephalic/Non-cephalic
First twin in non-cephalic
|
503 (53.6)
376 (40.1)
58 (6.2)
|
276 (67.5)
131 (32.0)
2 (0.5)
|
< 0.0001
|
Gestational age at delivery (wk) Mean±SD
32 wk 0 days to 33 wk 6 days
34 wk 0 days to 36 wk 6 days
37 wk 0 days to 38 wk 6 days
≥39 wk 0 days
|
37.01± 1.35
30 (3.2)
328 (35.0)
560 (59.7)
20 (2.1)
|
37.51± 1.17
3 (0.7)
115 (28.1)
270 (66.0)
21 (5.1)
|
< 0.0001
< 0.0001
|
Interval between deliveries (min) Mean±SD
|
2.2±3.2
|
12.2±21.2
|
< 0.0001
|
Use of antenatal corticosteroids
|
274 (29.2)
|
78 (19.1)
|
< 0.0001
|
Chorionicity at birth
Dichorionic- diamnionic
Monochorionic-diamnionic
Monochorionic-monoamniotic
Undocumented
|
699 (74.5)
214 (22.8)
1 (0.1)
24 (2.6)
|
304 (74.3)
92 (22.5)
1 (0.2)
12 (2.9)
|
0.91
|
PrlCS- pre-labor cesarean section. IOL- induction of labor.
Table 2. Neonatal outcomes in women who underwent pre-labor cesarean section (PrlCS) or induction of labor (IOL).
Outcome n (%)
|
PrlCS (n=938)
|
IOL
(n=409)
|
Odds Ratio
(95% CI)
|
P
|
Composite primary outcome
|
31 (1.7)
|
16 (2.0)
|
0.8 (0.4-1.6)
|
0.61
|
Death
|
15 (0.8)
|
6 (0.7)
|
1.1 (0.4-3.3)
|
0.88
|
Serious neonatal morbidity
|
16 (0.9)
|
10 (1.2)
|
0.7 (0.3-1.6)
|
0.4
|
Birth trauma *
|
2 (0.1)
|
2 (0.2)
|
0.4 (0.0-4.8)
|
0.49
|
Apgar score <4 at 5 min
|
2 (0.1)
|
3 (0.4)
|
0.28 (0.0-1.7)
|
0.24
|
Abnormal level of consciousness †
|
0
|
0
|
-
|
|
≥2 Seizures within 72 hr after birth
|
0
|
2 (0.3)
|
|
0.09
|
Assisted ventilation ‡
|
12 (0.7)
|
2 (0.3)
|
2.61 (0.6-11.9)
|
0.13
|
Neonatal sepsis within 72 hours after birth
|
0
|
0
|
-
|
|
Necrotizing enterocolitis
|
0
|
1 (0.1)
|
|
0.30
|
Cystic periventricular leukomalacia
|
2 (0.1)
|
0
|
|
0.99
|
PrlCS- pre-labor cesarean section. IOL- induction of labor.
*Birth trauma: Long-bone fracture, other bone fracture, facial-nerve injury at 72 hr of age or at discharge, intracerebral hemorrhage.
†Abnormal level of consciousness: Coma, stupor or decreased response to pain, hyperalert, drowsy, or lethargic.
‡Assisted ventilation for ≥24 hr by means of endotracheal tube, inserted within 72 hr after birth.
Table 3. Maternal outcomes in women who underwent pre-labor cesarean section (PrlCS) or induction of labor (IOL).
Outcome n (%)
|
PrlCS (n=938)
|
IOL
(n=409)
|
Odds Ratio
(95% CI)
|
P
|
Death or serious maternal morbidity
Death
|
68 (7.3)
1 (0.1)
|
46 (11.3)
1 (0.2)
|
0.61 (0.4-0.9)
0.43 (0.0-7.0)
|
0.01
0.55
|
Hemorrhage
Blood loss ≥1500 ml
Blood transfusion
D&C of uterus after delivery*
|
58 (6.2)
19 (2.0)
49 (5.2)
3 (0.3)
|
39 (9.6)
14 (3.4)
29 (7.1)
6 (1.5)
|
0.62 (0.4-0.9)
0.58 (0.3-1.2)
0.72 (0.4-1.2)
0.2 (0.1-0.9)
|
0.02
0.13
0.17
0.03
|
Laparotomy
|
9 (1.0)
|
0 (0)
|
5.5 (1.10-Inf)
|
0.07
|
Genital tract injury×
|
3 (0.3)
|
0 (0)
|
1.7 (0.25-Inf)
|
0.67
|
Perineal third- or fourth-degree tear involving anal sphincter
|
0 (0)
|
4 (0.98)
|
0.1 (0-0.5)
|
0.01
|
Thromboembolism requiring anticoagulant therapy
|
5 (0.5)
|
1 (0.3)
|
2.2 (0.3-18.8)
|
0.47
|
Infection, excluding wound infection
|
16 (1.7)
|
5 (1.2)
|
1.40 (0.5-3.9)
|
0.51
|
Wound infection†
|
20 (2.1)
|
4 (1.0)
|
2.20 (0.7-6.5)
|
0.15
|
Wound dehiscence or breakdown
|
12 (1.3)
|
3 (0.7)
|
0.17 (0.5-6.2)
|
0.38
|
PrlCS- pre-labor cesarean section. IOL- induction of labor.
*D&C- Dilation and curettage.
× Genital Tract Injury: Need for hysterectomy; vulvar or perineal hematoma requiring evacuation; broad-ligament hematoma confirmed by means of ultrasonography, CT, or MRI; intraoperative damage to the bladder, ureter, or bowel requiring repair; fistula involving the genital tract.
†Wound infection: Infection requiring prolongation of hospital stay, infection requiring readmission to hospital, infection requiring repeated treatment as an outpatient.
Table 4. Neonatal outcomes in women whose indication for delivery was “advanced gestational age”.
Outcome n (%)
|
PrlCS (n==46)
|
IOL
(n=202)
|
Odds Ratio
(95% CI)
|
P Value
|
Composite primary outcome
|
0 (0)
|
9 (2.2)
|
|
0.35
|
Death
|
0 (0)
|
3 (0.8)
|
|
0.99
|
Serious neonatal morbidity
|
0 (0)
|
6 (1.5)
|
|
0.36
|
Birth trauma *
|
0 (0)
|
2 (0.5)
|
|
0.99
|
Apgar score <4 at 5 min
|
0 (0)
|
2 (0.5)
|
|
0.99
|
Abnormal level of consciousness †
|
0 (0)
|
0 (0.0)
|
N/E
|
|
≥2 Seizures within 72 hr after birth
|
0 (0)
|
1 (0.3)
|
|
0.99
|
Assisted ventilation‡
|
0 (0)
|
1 (0.3)
|
|
0.99
|
Neonatal sepsis within 72 hours after birth
|
0 (0)
|
0 (0)
|
N/E
|
|
Necrotizing enterocolitis
|
0 (0)
|
0 (0)
|
N/E
|
|
Cystic periventricular leukomalacia
|
0 (0)
|
0 (0)
|
N/E
|
|
PrlCS- pre-labor cesarean section. IOL- induction of labor.
*Birth trauma: Long-bone fracture, other bone fracture, facial-nerve injury at 72 hr of age or at discharge, intracerebral hemorrhage.
N/C- No Convergence. N/E- No Events.
†Abnormal level of consciousness: Coma, stupor or decreased response to pain, hyperalert, drowsy, or lethargic.
‡Assisted ventilation for ≥24 hr by means of endotracheal tube, inserted within 72 hr after birth.
Table 5. Maternal outcomes in women whose indication for delivery was “advanced gestational
Outcome n (%)
|
PrlCS (n=46)
|
IOL
(n=202)
|
Odds Ratio
(95% CI)
|
P Value
|
Death or serious maternal morbidity
Death
|
0 (0)
0 (0)
|
19 (9.4)
1 (0.5)
|
0.15 (0-0.7)
4.39 (0-83.4)
|
0.03
0.99
|
Hemorrhage
Blood loss ≥1500 ml
Blood transfusion
D&C of uterus after delivery
|
1 (2.2)
0 (0)
1 (2.2)
0 (0)
|
17 (8.5)
6 (3.0)
13 (6.5)
2 (1.0)
|
0.23 (0.0-1.8)
0.52 (0-2.8)
0.32 (0.0-2.5)
1.81 (0-15.3)
|
0.17
0.58
0.28
0.99
|
Laparotomy
|
0 (0)
|
0 (0)
|
-
|
|
Genital tract injury
|
0 (0)
|
0 (0)
|
-
|
|
Perineal third- or fourth-degree tear involving anal sphincter
|
0 (0)
|
1 (0.5)
|
4.39 (0-83.4)
|
0.99
|
Thromboembolism requiring anticoagulant therapy
|
0 (0)
|
0 (0)
|
-
|
|
Infection, excluding wound infection
|
0 (0)
|
2 (1.0)
|
1.81 (0-15.3)
|
0.99
|
Wound infection*
|
0 (0)
|
3 (1.5)
|
1.13 (0-7.6)
|
0.99
|
Wound dehiscence or breakdown
|
0 (0)
|
1 (0.5)
|
4.39 (0-83.4
|
0.99
|
age”.
PrlCS- pre-labor cesarean section. IOL- induction of labor.
*Wound infection: Infection requiring prolongation of hospital stay, infection requiring readmission to hospital, infection requiring repeated treatment as an outpatient.