The following is an article written by Henci Goer. I found this at: http://parenting.ivillage.com/pregnancy/plabor/0,,bgjt-p,00.html
The facts about VBAC
After years of slowly moving in the direction of establishing VBAC as the norm, prominent obstetricians and the American College of Obstetricians and Gynecologists (ACOG) did an about-face in the mid 1990s and began promoting elective repeat cesarean. As a result, the VBAC rate, which had steadily risen since 1980, fell from a peak of 28 percent in 1996 to 21 percent in 2000, a decline of 27 percent (23). The anti-VBAC campaign has had two prongs: the claim that planned repeat cesarean is as safe or nearly as safe for the mother and safer for the baby and the institution of criteria in the name of safety that act as a barrier to VBACs. (1,16). What changed?
Obstetricians have openly admitted that one reason for the turn around is reducing liability stemming from the scar giving way during labor, a concern that arose from some successful malpractice suits involving VBACs (1,29). This self-confessed incentive provides a powerful motive for bias, conscious or unconscious, against VBAC and a cause for skepticism of statements and policies favoring elective cesareans.
I contend that nothing changed. It remains as true as it ever did that VBAC is as safe as planned cesarean for the baby, safer for the mother, and much safer for any future pregnancies. Here is the research that backs my contention. You decide who’s right.
When is a repeat cesarean not necessary?
Doctors may cite the following as reasons for planned cesarean, but none are true disqualifiers for VBAC. Obstetricians also give rationales that have no basis in the research. These include indications such as mother past her due date, cervix not ready for labor at the due date, baby’s head still high at full term (22):
-Hospital lacks the ability to perform emergency cesarean around the clock: The general hospital population has about the same potential for a labor emergency as the potential for the scar giving way. If the hospital isn’t safe for a VBAC labor, then it isn’t safe for any woman to labor there.
-Prior cesarean for poor progress -- also known as “failure to progress,” “labor dystocia,” “cephalopelvic disproportion”: Eighteen studies report the VBAC rate when the first cesarean was performed for one of these reasons (15). All but two found that half or more of the group gave birth vaginally. Half the studies report rates between 60 and 69 percent, so your odds of vaginal birth with a supportive practitioner should be roughly two out of three.
-Suspected large baby: Ultrasound scans predicting weights over 8 lbs. 13 oz. (4,000 grams) will be wrong one-third to one-half of the time (15). Even when babies weigh more than 4,000 grams, the VBAC rate is about two out of three (30).
-Type of uterine scar not known: Unless the prior cesarean was done in Latin America or certain other countries or for the reasons listed under When would a VBAC be inadvisable?, the odds are 99 to 1 the scar is transverse (10).
-Low vertical uterine scar: Doctors perform a low vertical incision for cesarean deliveries of premature babies because the lower part of the uterus isn’t well enough developed yet for a transverse incision. Data suggest this scar is as strong as a transverse scar (24,33).
-More than one prior cesarean: Two studies reported rates of less than 2 percent and less than 1 percent (3,25),. A third said merely that the rate did not differ from the rate with one uterine scar (9). Overall, the chances of vaginal birth were two out of three.
-Twins: We haven’t much data on twins, but VBAC doesn’t seem to pose excess risk (11,25,27,35).
-Breech: External cephalic version is a procedure in which the doctor turns the baby head down in late pregnancy by manipulating the woman’s belly. What little data we have suggests this procedure is safe in women with prior cesareans (8,19,32).
-Labor induction is indicated: Large studies show that straight oxytocin (Pitocin) induction increases the incidence of symptomatic scar separation only slightly from 4 to 5 per 1,000 to 7 to 8 per 1,000 (21,30). The risk comes when prostaglandins are used. Prostaglandin E2 (dinoprostone), the type found in Prepidil and Cervidil, increases the incidence of the scar giving way to 25 per 1,000 (21). Prostaglandin E1 (misoprostol), the type found in Cytotec, raises it even higher, possibly much higher (12). Some evidence suggests that long, unproductive oxytocin inductions may also be a problem (20).
In any case, induction should be reserved for those situations where the risks of awaiting labor outweigh the risks of inducing it. This occurs far less often than the typical obstetrician thinks it does. One of the common reasons for induction is questionable: induction at 41 weeks. Others aren’t supported by the research at all: convenience inductions, induction for suspected big baby, induction for gestational diabetes, induction before 24 hours in a woman at full term with ruptured membranes, no signs of infection, and who tests negative for Group B strep (15). What are the potential risks of a cesarean?
The risks of planned repeat cesarean fall into three categories:
1. Risks of cesarean, compared with vaginal birth (14):
Cesarean section results in more pain, debility, and a longer recovery period. It substantially increases the risk of infection, injury to other organs, hemorrhage, and blood clots. These complications, in turn, increase the likelihood of prolonged hospitalization, hysterectomy, readmission to the hospital, and maternal death. Babies who were healthy before delivery are more likely to be born in poor condition or have breathing difficulties. In the long term, cesareans can lead to chronic pain or bowel problems, and they increase the risk of infertility, miscarriage, placental abruption (placenta detaching before the birth), and placenta previa (placenta overlaying the cervix).
2. Excess risks of planned cesarean versus labor:
Hysterectomy: In the Swiss study, three times as many women having planned cesareans required hysterectomies as women who labored (45 per 10,000 versus 16 per 10,000) (15,30). Among 29 other studies, comprising 18,500 planned cesareans and 38,700 labors after cesarean, hysterectomy rates were also tripled in the planned cesarean group (21 per 10,000 versus 7 per 10,000) (15).
Blood clot complications: In the Swiss study, planned cesarean doubled the risk of blood clot complications (43 per 10,000 versus 22 per 10,000) (30).
3. Risks that derive from accumulating cesareans. Some complications arise from the build-up of scar-tissue in the pelvic cavity. Some are likely due to accumulating uterine scars leaving bare patches in the uterine lining, the layer in which the placenta implants. Still others may be due to post surgical infection injuring delicate tissues such as the cilia lining the Fallopian tubes that link ovaries to uterus.
-Increased risk of injury to other organs during subsequent cesareans: Scar tissue makes successive cesareans more difficult technically to perform.
-Increased risk of chronic pain and bowel problems.
-Ectopic pregnancy -- embryo implants outside of the uterus: (Potentially life-threatening for mother, invariably fatal for the baby.) A study found no increase in ectopic pregnancy in women with one prior cesarean but half again the risk (3 percent versus 2 percent) in women with a history of more than one cesarean (18).
-Placental abruption -- placenta detaches before the birth: (Potentially life-threatening for mother and baby.) Two to four times the risk compared with an unscarred uterus depending on whether the woman’s first birth was a cesarean, or she has more than one prior birth and at least one cesarean (18).
-Placenta previa -- placenta overlays the cervix: (Potentially life-threatening for mother and baby.) More than four times the risk with one prior cesarean, seven times the risk with two to three, and forty-five times the risk with four (2).
-Placenta accreta or percreta -- placenta grows into or through the muscular wall of the uterus: (Particularly dangerous for mother and baby.) Eleven times the risk with multiple prior cesareans compared with one prior cesarean -- nearly 1 per 100 versus 1 per 1,000 (2). In a study of 109 cases of placenta percreta, 40 percent of women required transfusion of more than ten units of blood, nearly all had hysterectomies, and ten babies and eight mothers died (28).
Both placenta accreta and placenta previa: Eight out of ten women with both had prior cesareans (34). The risk for the combination was 35 times higher for women with a prior cesarean compared to women with unscarred uteruses.
How might care in VBAC labors differ?
VBAC labors shouldn’t be handled any differently from labors with an unscarred uterus with one possible exception. The most reliable symptom that the scar has opened and is causing problems is a sudden drop in the baby’s heart rate. For this reason, Dr. Bruce Flamm, preeminent VBAC researcher, recommends continuous electronic fetal monitoring (EFM). Others have argued that symptomatic scar separations happen no more often than other unpredictable obstetric emergencies (7). If women generally have not been shown to benefit, we should be cautious about subjecting women with prior cesareans to EFM’s disadvantages.
Here are some unjustified ways that doctors may manage VBAC labors:
-Refusal to allow an epidural: At one time doctors thought an epidural might mask the pain of the scar separating, but pain has been shown not to be a reliable symptom, and experts have long since agreed that epidurals should be permitted (13). That being said, epidurals pose one problem peculiar to VBACs. Some babies will experience an episode of slowed heart rate, and a drop in the fetal heart rate is the most reliable symptom of the scar giving way (15).
-Routine IV: IVs cause pain, decrease mobility and can cause fluid overload. Fluid overload can lead to a host of physiologic problems, some minor, some major, in babies and mothers (15). If you feel uncomfortable refusing an IV, compromise on a heparin lock. With a heparin lock, the IV catheter is inserted, but it is only connected to a short piece of tubing that is taped to your hand or arm. It frees you from the IV pole, but an IV can be plugged in at any time.
-No oral intake: You should at least be allowed to drink clear liquids. Hunger and especially thirst increase discomfort. Dehydration and starvation can diminish contraction strength and may make the baby’s blood more acidic, a symptom of fetal distress (15).
-Intrauterine pressure monitor: The theory is that the scar giving way will decrease uterine contraction pressures. However, an analysis of 76 cases of symptomatic scar separation found that in no case did monitoring contraction pressures internally diagnose the problem (31). Another study simulated scar breakdown in twenty women by recording uterine pressures in laboring women before and after incising the uterus during cesarean section (5). The monitoring device failed to show pressure changes in any of the women. Internal contraction monitoring increases the risk of infection, and in rare cases, the catheter can injure the placenta, pierce the uterus, or become entangled with the umbilical cord.
-Manual exploration of the uterus after the birth: There seems to be little value in identifying symptomless scar windows because they don’t seem to pose a risk in subsequent pregnancies. On the downside, the internal examination is extremely painful. The procedure also could increase the risk of infection or convert a small, harmless gap into a problem. In the sole reported case of maternal death due to bleeding from a scar that gave way, the uterus had been explored after the birth, but the rupture was missed (6).
Will a VBAC affect your postpartum recovery?
If you have a vaginal birth, the days and weeks after the birth are likely to be much easier because you won’t be recovering from major surgery. This will be even more important than it was the first time because you already have another child or children at home. A VBAC that ends in a repeat cesarean can be disappointing, but even so, most women are glad they tried.
When would VBAC be inadvisable?
Doctors agree that planned cesarean is preferred when the mother has a vertical (also called “classical”), T-shaped, or J-shaped uterine incision. However, in most countries, the low transverse incision has been the norm for many years. Reasons for a vertical incision include the placenta is overlaying the cervix (placenta previa), some breech presentations (the baby is buttocks, knees, or feet down), and some emergency cesareans.
What are the potential risks of VBAC?
-Symptomatic scar separation: The main fear with labor after a cesarean is that the scar will open enough to cause bleeding or for the umbilical cord or the baby to pass through the opening. Among thirty studies totaling 56,300 VBACs, the rate of symptomatic scar separation was 4 per 1,000 (15,30). Even so, few instances where this occurs result in harm to the baby, which is the real issue. The perinatal mortality rate (stillbirths and newborn deaths together) from this cause was 3 per 10,000. This did not differ from the perinatal mortality rate of 2 per 10,000 in 29,900 planned cesareans. Nor does planning a cesarean eliminate the risk of the scar giving way. Several large studies reported scar separation rates ranging from 2 to 3 per 1,000 with repeat cesarean, not much less than the 4 to 6 per 1,000 reported in VBAC labors (17,21,30).
-More likelihood of complications if the labor ends in a cesarean: You are somewhat more likely to have complications such as infection with a cesarean after labor compared with a planned cesarean. Nonetheless, planned cesareans have substantially higher complication rates than vaginal births, and most properly managed labors after a cesarean should end in vaginal birth.
In summary, VBAC introduces a slightly greater risk of serious complications relating to the scar, but this is more than counterbalanced by a host of complications that occur more frequently with cesarean section.
What is a reasonable VBAC rate?
Among 34 studies of labor after a prior cesarean, totaling 38, 700 women, all but one reported VBAC rates above 60 percent (15). Half reported rates between 70 and 79 percent. An analysis of 17,600 labors after cesarean in Switzerland reported a 75 percent rate (30). Therefore, with a midwife or doctor committed to VBAC, your overall odds of VBAC should be three out of four, and you would be well advised to seek another practitioner if yours has a rate less than 70 percent.
The odds of VBAC also shift up or down depending on various factors. As you would expect, you are more likely to have a vaginal birth than the overall average if you have had a prior vaginal birth, less likely if your prior cesarean was for poor progress or this baby is big. You are also less likely to have a vaginal birth if you are induced. Nonetheless, the VBAC rates still fall around 66 percent, or two out of three with supportive caregivers (3,9,26,30).
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