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The American Academy of Family Physicians (AAFP) has released an evidence-based clinical practice guideline on trial of labor after cesarean delivery (TOLAC). The recommendations replace the AAFP clinical recommendation on trial of labor versus elective repeat cesarean section for women with a previous cesarean section. The guideline, which was summarized in part in the August 2005 issue of Annals of Family Medicine, is available online at https://www.aafp.org/tolac.xml and is summarized in the accompanying table.

The evidence for the updated 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.

The peer-reviewed, published results of the AHRQ evidence report were used to create the AAFP guideline, and an adapted version of the Strength of Recommendation Taxonomy (SORT) was used to rate the strength of the evidence. Because two years had passed since the original evidence review was published, the TOLAC panel conducted a systematic review of new evidence through March 2004 following the same procedure used for the AHRQ evidence report. The updated search yielded only seven studies that received a fair to good rating, and these studies did not address the same outcomes or have the same study focus. Accordingly, without a body of new evidence for any key question, the TOLAC panel determined that there was no support for any substantive change to the original report. Therefore, the original evidence report was used as the evidence source for this guideline.

The panel’s objective was to provide an evidence-based clinical practice guideline for pregnant women with one previous cesarean delivery and their families, for the maternity care professionals attending their labor and delivery, for the maternity care facilities where they will labor and deliver, and for policy makers who care about trial of labor and maternity care for a woman. A maternity care facility is a birthing facility with a labor and delivery unit that has the capacity to provide appropriate monitoring and to provide a timely cesarean delivery when needed. A maternity care professional is someone who has privileges to manage normal labor and delivery.

There is fair to good evidence that 76 percent of women who attempt TOLAC are successful in having a vaginal birth. Labor induction or augmentation with oxytocin reduces the likelihood of success to 63 percent, and the use of prostaglandin ripening or induction further reduces the success rate to 51 percent. There is fair evidence that rates of maternal death and hysterectomy do not differ between elective repeat cesarean delivery and TOLAC, and that there is a small but significant increase in symptomatic uterine rupture in women attempting TOLAC (2.7 patients per 1,000 attempts). Studies of infection rates were limited by poor quality. The evidence for infant outcomes is poor; there may or may not be a slightly increased risk of infant death with TOLAC compared with elective repeat cesarean delivery. No relevant studies were found to address health status and health-related quality of life for women who attempted TOLAC or elective repeat cesarean delivery.

Based on this evidence, women with one previous cesarean delivery and a low transverse incision are candidates for and should be offered a trial of labor. [SORT rating A] Patients desiring TOLAC should be counseled that their chance for a successful vaginal birth after cesarean delivery is influenced by several factors (see accompanying table). [SORT rating B] 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]

Because there is no evidence that the provision of additional resources beyond those normally available to all laboring women improves maternal or neonatal outcomes for women attempting TOLAC, no recommendations could be made about restrictions on such deliveries. Because of concerns that efforts to limit the accessibility of TOLAC by requiring restrictive conditions during labor may force women to present late in labor, to place themselves at risk by lengthy travel to another facility during labor, or to submit to an unwanted cesarean delivery, TOLAC should not be restricted to facilities with available surgical teams present throughout labor, because there is no evidence that these additional resources result in improved outcomes. [SORT rating C] At the same time, it is clinically appropriate that a management plan for uterine rupture and other potential emergencies requiring rapid cesarean delivery should be documented for each woman under-going TOLAC. [SORT rating C]

Finally, maternity care professionals need to explore all issues that may affect a women’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.

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] At the same time, it is clinically appropriate that a management plan for uterine rupture and other potential emergencies requiring rapid cesarean delivery should be documented for each woman undergoing TOLAC. [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.

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