Vaginal Birth After Myomectomy -- Uterine Rupture Risks

My latest thing is trying to evaluate the risks of a vaginal birth now that I've had an incision all the way through my uterine wall. I have been advised to have a scheduled c-section by my surgeon. I've researched this topic before, and I even avoided the surgery for a long time because I knew that they would say I would have to have a c-section.

It looks like the risks are:

* up to 9% (4-9%) chance of a uterine rupture total (including
ruptures that occur prior to active labor, i.e. rupture at 28-34
weeks)

If the uterus was to rupture there is a:

* 1 in 3,300 births chance of the baby dying, and a
* 1 in 5,000 risk of hysterectomy
Is vaginal birth after cesarean risky?


Additionally:

"The risk of uterine rupture is 1 in 500 even with planned repeat
cesarean versus 1 in 10,000 with an unscarred uterus."
CIMS Alarmed by Highest US Cesarean Rate Ever

"women having planned cesareans for a subsequent birth were three
times as likely to have hysterectomies as women planning VBACs: 1 in
220 versus 1 in 625."
Is vaginal birth after cesarean risky?

"For women being induced without use of prostaglandin, the odds went
up only slightly, but when labor induction included prostaglandin,
they soared to 1 in 900 for hysterectomy and 1 in 770 for infant
death."


This in contrast to the rupture rates among VBACs with a transverse
incision:

”1 in 625 with a planned repeat cesarean,
1 in 192 with starting labor on their own,
1 in 130 with an induction of labor but without using prostaglandin
to soften the cervix first,
1 in 41 with labor inductions that included prostaglandin.”
Is vaginal birth after cesarean risky?

and

"cord prolapse, or antepartum hemorrhage) in any women giving birth,
is approximately 2.7%, or up to 30 times as high as the risk of
uterine rupture with planned vaginal birth after cesarean"
[Note that they are referring to VBAC after low transverse section
data)

So, if 9 women will have uterine rupture does that mean that the
other 91 women shouldn't be allowed to do a trial of labor?

I was looking in A guide to effective care in pregnancy and childbirth 3rd Edition (Enkin, Keirse, Neilson, Crowther, Duley, Hodnett and Hofmeyr, Oxford University Press) and found these interesting quotes:

"Maternal mortality and serious morbidity are fortunately very rare, and for this reason estimates of their frequency are imprecise. A large meta-analysis showed maternal mortality of 2.8 per 10,000 for women undergoing trials of labor, and 2.4 per 10,000 for women having an elective cesarean. Uterine dehiscence (asymptomatic separations of the uterine scar) or ruptures occur in less than 2% of trials of labor, the same proportion as is seen among women who have routine repeat cesareans. Most of these are asymptomatic and of no clinical importance."

"The rate of maternal death associated with cesarean section (approximately 4 per 10,000 births) is four times that associated with all types of vaginal birth (1 per 10,000 births). The maternal death rate associated with elective repeat cesarean section (around 2 per 10,000 births), although lower than that associated with cesarean sections overall, is still twice the rate associated with all vaginal deliveries, and nearly four times the mortality rate associated with normal vaginal birth (0.5 per 10,000 births)."

"...the probability of requiring an emergency cesarean section for acute other conditions (fetal distress, cord prolapse, or antepartum hemorrhage) in any women giving birth, is approximately 2.7%, or up to 30 times as high as the risk of uterine rupture with planned vaginal birth after cesarean"[Note that they are referring to VBAC after low transverse section data)

"Hospitals whose capabilities are so limited that they cannot deal promptly with problems associated with a planned vaginal birth after cesarean are also incapable of dealing appropriately with other obstetrical emergencies."

It is strange how the ob/gyn field reacts towards childbirth and its complications, even though it is a natural process. When you contrast what I've learned through my experience with fibroids, that many women who have finished having children are advised to have hysterectomy for these benign tumors though they can be safely excised via abdominal or laparoscopic surgery. In contrast, a doctor specializing in the colon, when presented with a patient with a polyp in the colon, does not proceed to remove the colon, s/he would remove the polyp alone. And then I was looking for stats on complication rates after other surgeries and saw this, perhaps not the best comparison but still:


"The Duke analysis found that the mortality rates for heart failure patients was 11.7 percent, compared to 6.6 percent for coronary artery disease patients and 6.2 percent for patients without heart disease. In terms of readmission rates after surgery, heart failure patients had a 20 percent rate, compared to 14.2 percent for coronary artery disease patients and 11 percent for patients with out heart disease."
from: Heart failure patients at increased risk during non-cardiac surgery


So the death rate from having non-heart related surgeries on patients with heart disease is really high. Much higher than the risks associated with childbirth, and much higher than the risks of uterine rupture. It just boggles the mind how different these specialties are when they approach patient care.

"Early findings suggest that a the greatest influence on a woman's decision to attempt a VBAC trial of labor is her personal philosophy of birth (normal life event vs potential disaster) and the attitude of her healthcare provider surrounding VBAC trial of labor. The final findings will be presented at the 2004 ACNM Annual Meeting in New Orleans, Louisiana."Vaginal Birth After Cesarean (ACNM 48th Meeting)

While uterine rupture is slightly more likely with planned vaginal birth (5 per 1,000 versus 2 per 1,000 for a repeat cesarean), newborn outcomes do not differ. With appropriate care, 7 out of 10 women or more laboring after a cesarean will birth vaginally.
CIMS Alarmed by Highest US Cesarean Rate Ever

"Leaving aside that cesareans impose other risks that balance out the risk of uterine rupture during a VBAC, commentators on the Washington State data deemed the 1 in 3,300 chance of losing the baby during a spontaneous VBAC labor was sufficient to mandate planned repeat cesarean. The odds of amniocentesis precipitating a miscarriage fall somewhere between 1 in 200 and 1 in 400, more than ten times the risk of the baby dying from a VBAC-related uterine rupture. Yet obstetricians aren’t lobbying for an end to amniocentesis on the grounds that it is too hazardous."Is vaginal birth after cesarean risky?


"Even the way in which the Washington study data was presented was biased against VBAC. The article stated that spontaneous VBAC labor increased the risk of rupture 3.3-fold compared with repeat cesarean, a statistic quoted in media articles. This sounds alarming, but the absolute difference was four women per thousand, a miniscule number when you consider that two-thirds of women experiencing uterine rupture will suffer nothing worse than the cesarean they would have had in any case had they not decided on a VBAC."
Is vaginal birth after cesarean risky?


Increased risks are associated with:

• Gestational age of at least 42 weeks also raised the risk for a negative outcome.
  Results of the National Study of Vaginal Birth After Cesarean in Birth Centers (scroll down a bit)
  
  
• “Awaiting spontaneous labor beyond 40 weeks of gestation decreases the likelihood of successful VBAC but does not increase the risk of uterine rupture”
  Practice Guidelines: ACOG Releases Guidelines for Vaginal Birth After Cesarean Delivery
  
  
• “Approximately 50% of uterine ruptures that occur may be catastrophic, with significant rates of morbidity and mortality to both the fetus and mother.”
  Uterine Rupture and Vaginal Birth After Cesarean Section: An Historical Enigma
  
  
• “One study showed that women who had a previous vaginal delivery prior to attempting a trial of labor had a rupture
  rate that was one fifth the rate of women who did not have a previous vaginal delivery.”
  Uterine Rupture and Vaginal Birth After Cesarean Section: An Historical Enigma
  
  
• “Prior classical uterine incision is associated with a rate of uterine rupture of up to 12%.”
  Minimizing Obstetrical Risk: Vaginal Birth After Cesarean Section
  
  
• “Interdelivery interval: If the prior delivery was less than 18 months, there was a 3-fold increased incidence of uterine rupture compared with women having a longer interdelivery interval” and
  “Maternal age: Women over 30 years of age were 3 times more likely to experience a uterine rupture than those under 30 years”
  “Number of prior cesarean births: Women with 2 or more prior cesareans had a 3-fold increase in the incidence of uterine rupture (1.7%) compared with women with only 1 prior cesarean (0.6%).[9]”
  “Single-layer vs double-layer uterine closure: The 1-layer closure technique is associated with a 4-fold increase in the incidence of uterine rupture (3.1%) compared with prior 2-layer uterine closure (0.5%).”

Vaginal Birth After Cesarean (ACNM 48th Meeting)


"Pain at the scar does not reliably indicate uterine rupture. Caesareans for this reason often find intact scars.
Changes in contraction strength do not reliably indicate rupture, so routine intrauterine pressure catheters have little value.
Manual exploration of the scar results in both false positives and false negatives. False positives lead to unnecessary surgery. Wound openings without other symptoms probably need no repair anyway. The exploration (which is painful) may introduce infection and could potentially convert a wound opening into a rupture."http://www.bambi-bangkok.org/magazine/2000/b2_aug00.htm

"The majority of dehiscences after lower segment transverse incisions are 'silent', 'incomplete', or incidentally discovered at the time of repeat cesarean section. The potential dangers of uterine rupture are related to the rapid 'explosive' rupture, which is most likely, to be seen in women who have a classical midline scar. Rupture of the scar after a classical cesarean section is not only more serious than rupture of a lower segment scar, it is also more likely to occur. Rupture may occur suddenly during the course of pregnancy, prior to labor, and before a repeat cesarean section can be scheduled. A review of the literature at a time when classical cesarean section was still common, showed a 2.2% rate of uterine rupture with previous classical cesarean sections and a rate of 0.5% with previous lower segment cesarean sections. That is, the scar of the classical operation was more than four times more likely to rupture in a subsequent pregnancy than that of the lower segment incision.

Unfortunately, even in the older literature, there are very few data on the risk of uterine rupture of a vertical scar in the lower segment. One 1966 study reported an incidence of rupture of 2.2% in classical incision scars, 1.3% in vertical incision lower segment scars, and 0.7% in transverse incision lower segment scars. The distinction between the risk of rupture of vertical and transverse lower segment scars may be related to extension of the vertical incision from the lower segment into the upper segment of the uterus.

The uncertain denominators in the reported series make it difficult to quantify the risk of rupture with a previous classical or vertical incision lower segment scar. It is clear, however, that the risk that rupture may occur, that it may occur prior to the onset of labor, and that it may have serious sequelae, are considerably greater with such scars than with transverse incision lower segment scars. It would seem reasonable that women who have had a hysterotomy, a vertical uterine incision, or an 'inverted T incision, be treated in subsequent pregnancies in the same manner as women who have had a classical cesarean section, and that trial of labor, if permitted at all, should be carried out with great caution, and with acute awareness of the increased risks that are likely to exist."
Labor and birth after previous cesarean, 4.4 Type of previous incision in the uterus

The length of time from your c-section to your current due date is another issue. If less than 12 to 24 months will have passed since your c-section, your health-care provider will question whether there has been sufficient time for healing. Is the scar site strong enough to go through labor without separating? The highest risk for uterine rupture during labor is during the first year after a cesarean delivery. The risk of uterine rupture decreases over the following years. Other factors, such as surgical technique, suture material used, or infection may be involved as well. This issue is controversial and is being studied.
Midwife Elizabeth Stein on Vaginal Birth After Cesarean

“A woman's risk of uterine rupture increases with:

• Each additional uterine surgical scar. While a uterine rupture occurs in up to 8 per 1,000 women with one scar, up to 37 per 1,000 women with two scars develop a rupture.
  
• The use of medication to start (induce) labor. Use of misoprostol (Cytotec) or oxytocin (Pitocin) to induce labor has been linked to increased risk of uterine rupture during VBAC. In a recent study, uterine rupture occurred in:
  * 24.5 per 1,000 women who were induced with misoprostol.
  * 7.7 per 1,000 women who were induced with oxytocin.
  * 5.2 per 1,000 women who had a spontaneous labor.
  * 1.6 per 1,000 women who had a repeat cesarean without labor.
  However, careful use of oxytocin to aid (augment) a slow labor has rarely been linked to uterine rupture.4, 3
  
• Any uterine scar tissue that reaches above the lower, thinner part of the uterus. About 40 to 90 per 1,000 women with a vertical incision develop a rupture.

”
Rupture of the uterine scar and VBAC


“The type and location of the previous uterine incision helps to determine the risk of uterine rupture. The incidence of uterine rupture is 0.2% to 1.5% in a woman who attempts labour after a transverse lower-uterine-segment incision 14,16,18,27,45 and 1% to 1.6% after a vertical incision in the lower uterine segment. 46-49 The risk is 4% to 9% with a classical or “T” incision; and for this reason, a TOL after Caesarean is contraindicated in these situations.16,19,30 Shimonovitz et al. found the risk of uterine rupture after 0, 1, 2, and 3 VBAC deliveries to be 1.6%, 0.3%, 0.2%, and 0.35%, respectively, indicating that the risk of uterine rupture decreases after the first successful VBAC.”
SOGC Guidelines for Vaginal Birth After Previous Caesarian Birth

“Four studies have examined the relationship between the interdelivery interval and the rate of successful VBAC and uterine rupture.102-105 Esposito et al. examined 23 cases of uterine rupture and compared them to 127 controls.102 There was an increased risk of uterine rupture with a short interpregnancy interval (<6 months between pregnancies; <15 months between deliveries) compared to controls (17.4% vs. 4.7%, P=0.05).102 Shipp et al. reviewed 311 women who underwent a TOL after Caesarean less than 18 months after their Caesarean section and compared them to 2098 women who underwent a TOL after Caesarean after more than 18 months.103 The shorter interval was associated with a 3-fold increase in the risk of uterine rupture (2.25% vs. 1.05%: OR, 3.0; 95% CI, 1.2–7.2).103 Huang et al. reviewed 1185 women undergoing a TOL after Caesarean and noted no difference in the success of vaginal delivery in those with a shorter interval of <19 months (79% vs. 85.5%, P=0.12), but they did note a significant difference in successful
VBAC in women who underwent medical induction compared to spontaneous labour (14.3% vs. 86.1%, P<0.01).104 Their study noted no difference in the rate of uterine rupture.104 In 2002, Bujold et al. reported an observational study of 1527 women undergoing a planned TOL after Caesarean at different intervals from the index Caesarean delivery.105 The rates of uterine rupture were as follows: <12 months, 4.8%; 13 to 24 months, 2.7%; 25 to 36 months, 0.9%; and >36 months, 0.9%.105 After adjustment for such confounders as number of layers in the uterine closure, induction, oxytocin, and epidural use, the odds ratio for uterine rupture in a woman <24 months from her last delivery was 2.65 (95% CI, 1.08–6.46).105”
SOGC Guidelines for Vaginal Birth After Previous Caesarian Birth

Here's one more article about VBAC:
Predicting Cesarean Section and Uterine Rupture among Women Attempting Vaginal Birth after Prior Cesarean Section

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1201366/