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MS WordPerinatologist Corner - C.E.U/C.M.E. Modules
Vaginal Birth After Cesarean
Sponsored by The Indian Health Service Clinical Support Center
5. Management: Facility location and resources
Should V.B.A.C. be attempted in the smaller institutions where many of us work?
If women with a prior cesarean present these significant risks, is there data that supports our delivering them in our smaller facilities? From the composite of the above studies, the risk of uterine rupture during T.O.L.A.C. that we can quote to our patients with one prior cesarean is approximately 0.5%, or 1 in 200. During their prenatal course all prior cesarean patients should be counseled about T.O.L.A.C. vs. ERC and their preference elicited. They all should sign an informed consent covering the issues of uterine rupture, hysterectomy and loss of fertility, fetal loss and neurologic damage, and maternal death. The downsides of E.R.C.: anesthesia complications, excess blood loss, puerperal infection, and increased respiratory problems in the newborn, should also be detailed.
Document, document, document.
It is also a good idea to do your own third trimester ultrasound to localize the placenta and look for the "Swiss-cheese" appearance of the low anterior placenta that might suggest placenta accreta and a definite change of the birth plan.
Rozenberg reported that a factor protective of scar integrity is a thick lower uterine segment (greater than 3.5 mm) on ultrasound examination at 37 weeks of gestation. Though the previous scar itself is often difficult to visualize, the lower uterine segment thickness provided a sensitivity of 88% and specificity of 99%. The positive predictive value of the measurement is weak, suggesting that all thin lower uterine segments are not weak, rather that a thick lower uterine segment is usually strong.
Obviously fetal monitoring is critical in the management of these women when in labor. Augmentation of labor with oxytocin should be undertaken cautiously. The best current evidence suggests that prostaglandin preparations are contraindicated, thus making induction of such patients problematic. Blood should be available. Epidural analgesia is not contraindicated. Most importantly, and perhaps logistically most problematic, the attending physician and anesthesia personnel should be immediately available in house during these labors.
Several small studies examine the outcomes of T.O.L.A.C. in smaller facilities. Raynor in a level I hospital in rural western North Carolina with 951 births including 67 prior cesarean patients, had a 76% T.O.L.A.C. rate and experienced 2 asymptomatic scar dehiscences and no maternal or infant deaths.
Holland, in two level II hospitals in Alabama, had a low, 18% T.O.L.A.C. rate among over 18,000 births and experienced 1 rupture resulting in hysterectomy, and no deaths. In our own setting,
Leeman and Leeman at Zuni, NM, a level I facility with 735 births, made 290 antepartum transfers (including 55 prior cesareans) and 170 intrapartum transfers (including 3 prior cesareans) to Gallup (45 minutes away) or Albuquerque (2-3 hours away) and had no prior cesarean-related deaths.
AAFP Recommendations for Trial of Labor After Cesarean Delivery
The evidence for the following guideline was supplied by the Agency for Healthcare Research and Quality (AHRQ)
, which used a rigorous process for systematic identification, retrieval, evaluation, and analysis of all relevant research. Studies that focused on nulliparous women or vertical, lower vertical, or classical cesarean incisions, and studies that did not differentiate by scar type were excluded, as were studies focusing on complicated deliveries (e.g., vaginal breech, preterm, multifetal, low birth weight) or patients with conditions such as gestational diabetes, human immunodeficiency virus infection, or preeclampsia. The quality of evidence was rated as good, fair, or poor.
AAFP Recommendations for TOLAC |
| 1. Women with one previous cesarean delivery with a low transverse incision are candidates for and should be offered a trial of labor. [SORT rating A] |
| 2. Patients desiring TOLAC should be counseled that their chance for a successful VBAC is influenced by the following factors: [SORT rating B] |
| Positive factors (increased likelihood of successful VBAC) |
Maternal age less than 40 years Prior vaginal delivery (particularly prior successful VBAC) Favorable cervical factors Presence of spontaneous labor Nonrecurrent indication that was present for prior cesarean delivery |
| Negative factors (decreased likelihood of successful VBAC) |
Increased number of prior cesarean deliveries Gestational age greater than 40 weeks Birth weight greater than 4,000 g (8 lb, 13 oz) Induction or augmentation of labor |
| 3. Prostaglandins should not be used for cervical ripening or labor induction, because their use is associated with higher rates of uterine rupture and decreased rates of successful vaginal delivery. [SORT rating B] |
| 4. TOLAC should not be restricted to maternity care facilities with available surgical teams present throughout labor, because there is no evidence that these additional resources result in improved outcomes.* [SORT rating C] |
| 5. Maternity care professionals need to explore all issues that may affect a woman's decision (e.g., recovery time, safety). [SORT rating C]
No evidence-based recommendation can be made about the best way to present the risks and benefits of TOLAC to patients. |
| TOLAC = trial of labor after cesarean delivery; VBAC = vaginal birth after cesarean delivery.
*-"Maternity care facilities" refers to birthing facilities with labor and delivery units that have the capacity to provide appropriate monitoring and to provide a timely cesarean delivery when needed. patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, see page 1949 or http://www.aafp.org/afpsort.xml. Adapted from Wall E, Roberts R, Deutchman M, Hueston W, Atwood LA, Ireland B. Trial of labor after cesarean (TOLAC), formerly trial of labor versus elective repeat cesarean delivery for the woman with a previous cesarean delivery. |
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