Mona Lydon-Rochelle, Holt, Victoria L., Easterling,
Thomas R., Martin, Diane P. "Risk of Uterine Rupture during Labor
among Women with a Prior Cesarean Delivery" New England Journal of Medicine, Vl 345, No. 1, July 5, 2001.
A new study that looks at the risk of uterine rupture
during labor for VBACs (vaginal birth after cesarean-section) was
picked up by newspapers across the country, but many headlines
announced that VBACs are dangerous, a gross distortion of the study's
findings. National organizations including the ACNM and the
International Cesarean Awareness Network issued press releases, and
through the Grassroots Network CfM urged people to respond with letters
to the editor of their local newspapers.
The most important finding was that for hospital VBACs
(after one c-section) induction of labor significantly increases the
risk of uterine rupture, and the use of protoglandins greatly increases
the risk of rupture (15 times higher than those who had second
cesaraeans). In other words, the real problem is the first c-section
(which accounts for 2/3 of the US c-section rate of 22% in 1999), with
the risks greatly increased when labor is induced especially with
Data for women who had a first (single) baby by
c-section from 1987-1996, and subsequently gave birth to a second live
single infant during the same period of time (20,095 women, based on
Washington State records for hospital births), were analyzed in this
study. The study found:
|Repeat c-section without labor
||(11 of 6,980 women)|
|Spontaneous onset of labor
||(56 of 10,789 women)|
|Labor induced without prostaglandins
||(15 of 1,960 women)|
|Labor induced with prostaglandins
||(9 of 366 women)|
The study did not address many significant issues. For
example, uterine rupture can include anything from relatively minor
separations at the scar site, to sudden and catastrophic multiple large
tears of the uterus. However, accuracy of reported uterine rupture was
barely touched upon, and degrees of severity were not discussed.
Because the study focused only on the risk of uterine rupture, the
risks associated with the cesarean delivery procedure itself were not
discussed, even though these would be very relevant for informed
decision-making. There was no mention of other interventions that could
possibly affect outcomes, such as augmentation of labor (can cause
abnormally strong contractions) or the use of epidurals during labor
(can mask early symptoms of uterine rupture). The authors did
acknowledge that they lacked information regarding specific types and
dosages of prostaglandins used, although the controversial use of
Cytotec was not known to be used prior to the last year of the study.
Finally, there was no discussion or information regarding the timing
(number of weeks of gestation) or reasons for induction.
The study included only hospital births, and did not
distinguish between natural childbirth (no interventions) and standard
The study actually confirms what the midwifery
community has been saying for years: outcomes for VBACs that are
allowed to labor normally, without induction or augmentation, are good.
And women who have had a previous c-section are definitely not
candidates for labor inducing drugs, which exert added stress to a
uterine wall that is already weakened or at least changed by the scar
Women who are making decisions about attempting a VBAC
should understand the results of this study (and its limitations). In
addition, this information is essential for any woman who is "offered"
an elective c-section, or whose caregiver recommends a
c-section, so she can be aware that a c-section today significantly
increases risks associated with any future pregnancy. Of course, she
should also have full information on the relative risks of any
c-section for herself and her baby.
As ICAN states in their press release (see below),
"the risk of uterine rupture [for a VBAC] remains low when labor
is allowed to start on its own."