Table 5.
Summary of studies – guidelines or information for providers
| Study; Design; Country, setting; Funding |
Population; Study period |
Intervention & comparator (no. of participants) | TOLAC ratea | VBAC ratea | VBAC/TOLAC ratea | |
|---|---|---|---|---|---|---|
| Bellows (2016) Non-concurrent cohort US, tertiary care academic hospital Funding NR |
All women who underwent TOLAC, at least one prior CD & live, singleton gestation in cephalic presentation, 24 0/7 weeks of gestation July 1, 2009-December 31, 2013 |
Grp 1 (2009–2011): pre-2011 guideline (n = 450) | Grp 2 (2011–2013): post-2011 guideline implementation (offering TOLAC; inducing labor; administering oxytocin) (n = 781) | NR | Grp 1: NR (26.0%) Grp 2: NR (33.3%) |
Grp 1: 351 (78.1%) Grp 2: 616 (78.9%), p = 0.75 |
| Kosecoff (1987) Retrospective cohort US, acute, non-specialty, nonfederal hospitals > 150 beds. Non-industry funded |
Women with previous low transverse CS January 1979–December 1979 (time 1) January 1980–September 1980 (time 2) July 1981–June 1982 (time 3) |
Period 1 (January–December 1979) & Period 2 (January–September 1980): before NIH Consensus Development conference recommendations (n = 35 & n = 64) | Period 3 (1981–1982): after conference recommendations; women should be given TOLAC for potential VD (n = 70) | Period 1: 2 (5.7%) Period 2: 7 (10.9%) vs. Period 3: 20 (28.6%) |
Period 1: 2 (5.7%) Period 2: 4 (6.3%) vs. Period 3: 11 (15.7%) |
Period 1: 2 (100%) Period 2: 4 (57.1%) vs. Period 3: 11 (55.0%) |
| Pinette (2004) Non-concurrent cohort US, birth certificate & hospital reported data Funding NR |
All women with previous CS giving birth at 20 weeks of gestation or more 1998–2001 |
Grp 1 (1998): pre-exposure (birth certificate n = 1410; hospital data n = 1386) | Grp 2 (1999–2001): ACOG guideline revision (birth certificate data n = 4463; hospital data n = 4015) | NR | Birth certificate data: 1998: 424 (30.1%) vs. 1999: 327 (22.6%) 2000: 277 (17.9%) 2001: 193 (13.1%) 1988 vs. 2001, RR 2.8 (95% CI 2.5–3.2), p < 0.01 Hospital-reported data: 1998: 489 (35.3%) vs. 1999: 411 (28.2%) 2000: 321 (23.1%) 2001: 156 (13.3%) RR 3.5 (95% CI 3.1–4.2), p < 0.01 |
NR |
| Sanchez –Ramos (1990) Non-concurrent cohort US, regional perinatal center Funding NR |
Women with one or two previous CS, with low transverse or vertical scars not extending into uterine corpus 1986–1989 |
Grp 1 (1986–1987): before July 1, 1987 department-wide guideline change (n = 899) | Grp 2 (1988–1989): after July 1, 1987, new guidelines for intrapartum management (n = 1105) | 1986: 139 (31.7%) 1987: 193 (41.9%) vs. 1988: 402 (76.6%) 1989: 487 (84.0%); Difference: 52.2%, p < 0.0001 |
1986: 90 (20.5%) 1987: 142 (30.8%) vs. 1988: 342 (65.1%) 1989: 403 (69.5%); Difference: 48.9%; p < 0.0001 |
1986: 90 (64.7%) 1987: 142 (73.6%) vs. 1988: 342 (85.1%) 1989: 403 (82.8%); Difference: 18.0%; p < 0.0001 |
| Santerre (1996) Non-concurrent cohort US, hospitals Funding NR |
Women with a previous CS 1987–1991 |
Grp 1 (before 1987–1988): before practice guideline implementation (n = NR) | Grp 2 (after Oct. 1988): ACOG practice guideline, prior cesarean section no longer a reason for repeat cesarean (n = NR) | NR | VBAC rate in US (data for Massachusetts hospitals NR) 1985: 6.6% 1986: 8.5% 1987: 9.8% 1988: 12.6% vs. 1989: 18.5% 1990: 20.4% 1991: 24.2% 1992: 25.1% 1993: 25.4% |
NR |
| Studnicki (1997) Non-concurrent cohort US, nonfederal acute care provider hospitals Funding NR |
Women with prior CS 1990–1993 |
Grp 1 (1990–1992): before practice guidelines (n = 66,702) |
Grp 2 (1993): after legislatively imposed practice guidelines (n = 23,142) | NR | 1990: 4816 (21.8%) 1991: 5540 (25.6%) 1992: 6133 (26.7%) vs. 1993: 7151 (30.9%) |
NR |
| Zweifler (2006) Non-concurrent cohort US, California Department of Health Services Birth Statistical Master Files Funding NR |
Women who previously gave birth by cesarean delivery & had singleton birth planned in a California hospital 1996–2002 |
Grp 1 (1996–1999): before ACOG VBAC guideline revision (n = NRb) | Grp 2 (2000–2002): after ACOG VBAC guideline revision (n = NRb) | Attempted VBAC: Grp 1: NR (24.0%) Grp 2: NR (13.5%) Difference: 44% decrease, p < 0.001 |
1996–2002: 61,684 (16.0%) | NR |
no. number, TOLAC trial of labor after cesarean, VBAC vaginal birth after cesarean, US United States, NR not reported, CD cesarean delivery, Grp group, CS cesarean section, NIH National Institute of Health, VD vaginal delivery, vs. versus, ACOG American College of Obstetricians and Gynecologists, RR relative risk, CI confidence interval
aResults of statistical tests or summary statistics were extracted whenever these were reported within studies
bStudy reported number of live births separately from number of women; table reflects data for number of women whenever this was reported