Pocket ObGyn – Vaginal Birth After Cesarean
See Abbreviations
Definitions (Obstet Gynecol 2010;116:450)
- TOLAC:Trial of labor after prior cesarean delivery
- VBAC:Vaginal birth after prior cesarean delivery
- ERCD: Elective repeat cesarean delivery
Selection of Candidates
- 1 or 2 cesarean deliveries via low transverse OR low vertical Unk scar is NOT contraindication to TOLAC unless high suspicion for classical hysterotomy.
- No contraindication to vaginal deliv (eg, placenta previa)
- Overall success rate of TOLAC is 60–80%
- rate of successful TOLAC: Prior vaginal birth, spontaneous labor
- ¯ rate of successful TOLAC: Recurring indication for prior c/s (labor dystocia), increased mat age, nonwhite ethnicity, GA > 40 w, mat obesity, preeclampsia, short inter-Preg interval, increased birth weight
- Online NICHD VBAC success rate calculator https://mfmu.bsc.gwu.edu/PublicBSC/ MFMU/VGBirthCalc/vagbirth.html
| Maternal risks associated with TOLAC | |||
| Elective rpt
c-section (%) |
TOLAC w/
1 prior c-section (%) |
TOLAC w/
2+ prior c-sections (%) |
|
| Endometritis | 1.5–2.1 | 2.9 | 3.1 |
| Operative injury | 0.42–0.6 | 0.4 | 0.4 |
| Bld xfusion | 1–1.4 | 0.7–1.7 | 3.2 |
| Hysterectomy | 0–0.4 | 0.2–0.5 | 0.6 |
| Uterine rupture | 0.4–0.5 | 0.7–0.9 | 0.9–1.8 |
| Mat death | 0.002–0.004 | 0.002 | — |
| Neonatal risks associated with TOLAC | ||
| Elective rpt c-section (%) | TOLAC (%) | |
| Stillbirth 37–38 w | 0.08 | 0.38 |
| Stillbirth >39 w | 0.01 | 0.16 |
| Hypoxic/ischemic encephalopathy | 0–0.13 | 0.08 |
| Respiratory morbidity | 1–5 | 0.1–1.8 |
| Hyperbilirubinemia | 5.8 | 2.2 |
| Neonatal death (<1 mo) no signif change; perinatal death (<1 w) 0.01% w/ ERCD; 0.13% w/ TOLAC | ||
Delivery Considerations
- Misoprostol should NOT be used for IOL given elevated risk of uterine rupture Risk of uterine rupture: 5/1000 (NEJM 2001;345:3)
- Continuous fetal monitoring should be employed
- Maintain high suspicion for signs/sx of uterine rupture, including: New onset uterine pain, loss of fetal station, new abnormalities of the fetal heart tracing, vaginal bleeding, & mat hemodynamic instability
- Staff (OB & anesthesia) must be immediately available for emergent c-section