Blog: Less restrictive guidelines issued on vaginal birth after c-section
Last week the American Congress of Obstetricians and Gynecologists released new guidelines that say, “Attempting a vaginal birth after cesarean (VBAC) is a safe and appropriate choice for most women who have had a prior cesarean delivery, including for some women who have had two previous cesareans.”
click to enlargeDr. John Thorp
Now
that these new, less restrictive guidelines are in place, mothers-to-be
facing decisions about vaginal birth after cesarean section (VBAC) need
to keep two important numbers in mind.
The first is their
likelihood of having a successful VBAC, which is generally quoted as
60-70 percent. That proportion goes up if the woman has had a previous
vaginal birth or if her previous abdominal delivery was for a reason
that is unlikely to repeat itself, such as a breech delivery. The
number declines if labor is induced rather than allowing a natural
progression or as her baby’s size increases.
The second important
number is the likelihood of the uterine scar coming open prior to
delivery, which generally happens less than 1 percent of the time.
Some of these ruptured wounds will be minor and of little consequence,
but some are obstetrical emergencies that endanger the life and long
term health of the baby. Scar rupture risk increases when labor is
induced or stimulated (with medicines to speed labor up) and also
increases as the baby increases in size. We are poor estimators of
fetal weight, even with ultrasound, so the clinical usefulness of baby
size estimates are of little practical help to clinicians or mother.
Thus,
the woman making a decision about VBAC must keep these two
probabilities in mind. Ultimately, final decisions turn on how the
individual values natural childbirth and her fear, or lack thereof,
about surgery.
Women attempting VBAC should do so in a hospital
that can respond in a timely fashion to the rare but serious risk of
scar rupture.
