Vaginal Birth After Caesarean - Eligibility

Eligibility

Eligibility to pursue a VBAC varies widely by provider and birth setting (hospital, birthing center, or home). Some commonly employed criteria include:

• If the previous caesarean(s) involved a low transverse incision there is less risk of uterine rupture than if there was a low vertical incision, classical incision, T-shaped, inverted T-shaped, or J-shaped incision.
• A previous successful vaginal delivery (before or after the caesarean section) increases the chances of a successful VBAC.
• The reason for the previous caesarean section should not be present in the current pregnancy.
• The more caesarean sections that a woman has had, the less likely she will be eligible for VBAC.
• The presence of twins will decrease the likelihood of VBAC. Some doctors will still allow VBAC if the twins are positioned properly for birth.
• VBAC may be discouraged if there are other medical complications (such as diabetes), if the mother is over 40, if the pregnancy is post due date, or if the baby is malpositioned.

Some contraindications of a VBAC include:

• Maternal request for elective repeat CS after counselling
• Maternal or fetal reasons to avoid vaginal birth in current pregnancy
• Previous uterine incision other than transverse segment including classical
• Previous complicated lower uterine segment transverse incision
• Unknown previous uterine incision
• VBAC after two or more prior lower uterine segment transverse CS is controversial
• Previous uterine rupture
• Previous hysterotomy or myomectomy entering the uterine cavity

According to ACOG guidelines, the following criteria may reduce the likelihood of VBAC success but should NOT preclude a trial of labor: having two prior caesarean sections, suspected fetal macrosomia (fetus greater than 4000-4500 grams in weight), gestation beyond 40 weeks, twin gestation, and previous low vertical or unknown previous incision type, provided a classical incision is not suspected.

Depending on the provider, special precautions may be encouraged during a trial of labor following a caesarean section, including IV or IV port placement, continuous or intermittent fetal monitoring, and conservative or absent labor induction and augmentation using chemical stimulants. Other intrapartum management options, including analgesia/anesthesia, are identical to those of any labor and vaginal delivery.