09. tbl. 94. árg. 2008
Fræðigrein
Vaginal birth after one previous cesarean section
Objective: To evaluate the frequency of different modes of delivery after one previous cesarean section and those factors which may influence mode of delivery.
Material and methods: During the study period (1.1.2001-31.12.2005) 925 women with a previous cesarean section and a following singleton pregnancy were identified and included. Information regarding mode of delivery, induction of labor, instrumental delivery, the urgency and indications for first and second cesarean section, birth weight and Apgar scores were collected retrospectively.
Results: Trial of labor (TOL) was initiated for 564 women of which 61% were successful while 39% delivered by an emergent cesarean section. In total, 346 women delivered vaginally (37%), 341 women (37%) delivered with an elective cesarean section and 238 (26%) underwent an emergency cesarean section. The VBAC rate increased during the study period, from 35% to 46%. Women who underwent an elective cesarean section due to fetal malpresentation (most often breech) in their first pregnancy were significantly more likely to have a successful VBAC in their second pregnancy (53%) compared with women who had an elective cesarean section for any other indication (21%) (p<0.0001). Uterine rupture occurred in six women (1%) during TOL, five underwent an emergency cesarean section and had healthy infants while there was one intrapartum fetal death. No correlation was found between birth mode and Apgar scores at five minutes. Perinatal mortality rate was 5,4?. Trial of labor was less likely to succeed if the infant?s birth weight was >4000 grams compared with <4000 grams (p<0.01).
Conclusion: The results of this study indicate that VBAC is a safe option for women with a history of one previous cesarean section while in the hospital setting where there are resources for an immediate cesarean section.
Figure 1. Birth after one previous cesarean section.
Figure 2. VBAC ratio for women giving birth after one previous cesarean section, by year.
Figure 3. Flow chart; mode of delivery after one cesarean section.
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Table I. Urgency of previous cesarean section and trials of labor. |
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|
Previous cesarean section |
Trial of labor |
Successful trial of labor |
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|
Elective cesarean section |
117/201 |
(58%) |
79/117 |
(68%) |
|
Emergent cesarean section |
449/724 |
(62%) |
268/449 |
(60%) |
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Table II. Indications for elective cesarean sections in first and second delivery. |
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Indication |
No. in first delivery |
No. in second delivery |
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|
Previous cesarean section |
|
|
17 |
(5%) |
|
Malpresentation (most often breech) |
118 |
(59%) |
38 |
(11%) |
|
Cephalopelvic disproportion |
37 |
(19%) |
55 |
(16%) |
|
Preeclampsia |
14 |
(7%) |
13 |
(4%) |
|
Placenta previa |
4 |
(2%) |
2 |
(1%) |
|
Fear of birth, high-risk pregnancy, poor obstetric history |
4 |
(2%) |
29 |
(9%) |
|
Fetal growth restriction |
5 |
(3%) |
4 |
(1%) |
|
Congenital malformations of uterus or uterine leiomyoma |
4 |
(2%) |
5 |
(2%) |
|
Other or indeterminable indication |
10 |
(5%) |
30 |
(9%) |
|
Not specified |
5 |
(3%) |
148 |
(43%) |
|
Table III. Trial of labor (TOL) and successful TOL for women giving birth by elective cesarean section in previous delivery. |
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|
Indication for previous cesarean section |
No. |
Trial of labor - No.* |
Successful trial of labor - No. |
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|
Malpresentation |
118 |
83 |
(70%) |
62 |
(75%) |
|
Other indications |
83 |
33 |
(40%) |
17 |
(52%) |
*p<0,0001
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Table IV. Indications for emergent cesarean sections in first and second delivery. |
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Indication |
No. in first delivery |
No. in second delivery |
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|
Failure to progress / cephalopelvic disproportion |
403 |
(56%) |
120 |
(50%) |
|
Fetal distress |
151 |
(21%) |
35 |
(15%) |
|
Failure to progress / cephalopelvic disproportion AND fetal distress |
83 |
(12%) |
21 |
(9%) |
|
Failed instrumental delivery |
36 |
(5%) |
5 |
(2%) |
|
Failed induction of labor |
22 |
(3%) |
10 |
(4%) |
|
Severe preeclampsia |
11 |
(2%) |
5 |
(2%) |
|
Placenta previa |
7 |
(1%) |
4 |
(2%) |
|
Uterine rupture (or suspicion of such) |
0 |
(0%) |
6 |
(3%) |
|
Other or indeterminable indication |
6 |
(1%) |
11 |
(5%) |
|
Not specified |
4 |
(1%) |
21 |
(9%) |
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Table V. TOL and successful TOL for women giving birth by emergent cesarean section in previous delivery. |
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|
Indication for previous cesarean section |
No. |
Trial of labor - No. |
Successful trial of labor - No. |
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|
Failure to progress / fetal-pelvic disproportion |
403 |
253 |
(63%) |
156 |
(62%) |
|
Fetal distress |
151 |
104 |
(69%) |
66 |
(64%) |
|
Failure to progress / fetal-pelvic disproportion AND fetal distress |
83 |
48 |
(58%) |
24 |
(50%) |
|
Failed instrumental delivery |
36 |
18 |
(50%) |
8 |
(44%) |
|
Other |
51 |
25 |
(50%) |
13 |
(52%) |
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Table VI. Neonatal outcomes. |
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|
Neonatal diagnosis |
Children whose mothers attempted vaginal delivery |
Children whose mothers did not attempt vaginal delivery |
p-value |
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|
Apgar score ≤ 6 at 1 minute |
124 |
(22%) |
39 |
(11%) |
<0,0001 |
|
Apgar score ≤ 6 at 5 minutes |
13 |
(2%) |
5 |
(2%) |
0,25 |
|
Birth trauma |
14 |
(3%) |
2 |
(1%) |
0,02 |
|
Respiratory distress |
23 |
(4%) |
18 |
(5%) |
0,41 |
|
Perinatal mortality rate |
2 |
(0,4%) |
2 |
(1%) |
0,62 |