Table 5 Summary of studies – guidelines or information for providers

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 = NR^b)

Grp 2 (2000–2002): after ACOG VBAC guideline revision (n = NR^b)

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