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Definition of VBAC (Vaginal Birth After Cesarean Section)
Vaginal birth after cesarean section. In cesarean section, the obstetrician makes a surgical incision through the wall of the uterus to deliver the baby, then sutures (stitches) the incision closed. The SCAR that forms when the surgical wound heals is somewhat weaker than the surrounding muscle of the uterus.
When the incision is low and horizontal (transverse) in the uterus this slight weakness has little consequence. If the uterine incision runs vertically, however, there is an increased risk that the wall of the uterus could rupture along the scar during the intense contractions of labor and delivery.
Uterine rupture is life threatening for the woman and the baby.
Risks of VBAC
The obstetrician attempts to assess the likelihood of uterine rupture as the woman’s pregnancy becomes advanced. The risk for uterine rupture is high enough with a vertical uterine scar that most obstetricians strongly discourage the woman from attempting vaginal delivery with subsequent pregnancies.
If the obstetrician believes the risk for uterine rupture is low, which is usually the case with the low horizontal scar, VBAC is of little additional risk for the woman. Other factors that may influence the decision between a woman and her obstetrician about VBAC include the reason for the previous cesarean section and the woman’s overall health status in her current pregnancy.
About half of women who have cesarean deliveries are able to have vaginal deliveries in subsequent pregnancies.
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