Saturday, February 02, 2008

Repeated VBACs are safe; repeated cesareans are not

I am taking a brief brake from my serialized birth story to report on a study out of Case Western that just came out in Obstetrics & Gynecology (2008;111:285-291).

The study's OBJECTIVE: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs.

METHODS: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery.

RESULTS: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter.

CONCLUSION: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy.

Contrast that study with another from Obstetrics & Gynecology (2006;107:1226-1232) which found that there is maternal morbidity associated with multiple repeat cesareans.

OBJECTIVE: To estimate the magnitude of increased maternal morbidity associated with increasing number of cesarean deliveries.

METHODS: Prospective observational cohort of 30,132 women who had cesarean delivery without labor in 19 academic centers over 4 years (1999–2002).

RESULTS: There were 6,201 first (primary), 15,808 second, 6,324 third, 1,452 fourth, 258 fifth, and 89 sixth or more cesarean deliveries. The risks of placenta accreta, cystotomy, bowel injury, ureteral injury, and ileus, the need for postoperative ventilation, intensive care unit admission, hysterectomy, and blood transfusion requiring 4 or more units, and the duration of operative time and hospital stay significantly increased with increasing number of cesarean deliveries. Placenta accreta was present in 15 (0.24%), 49 (0.31%), 36 (0.57%), 31 (2.13%), 6 (2.33%), and 6 (6.74%) women undergoing their first, second, third, fourth, fifth, and sixth or more cesarean deliveries, respectively. Hysterectomy was required in 40 (0.65%) first, 67 (0.42%) second, 57 (0.90%) third, 35 (2.41%) fourth, 9 (3.49%) fifth, and 8 (8.99%) sixth or more cesarean deliveries. In the 723 women with previa, the risk for placenta accreta was 3%, 11%, 40%, 61%, and 67% for first, second, third, fourth, and fifth or more repeat cesarean deliveries, respectively.

CONCLUSION: Because serious maternal morbidity increases progressively with increasing number of cesarean deliveries, the number of intended pregnancies should be considered during counseling regarding elective repeat cesarean operation versus a trial of labor and when debating the merits of elective primary cesarean delivery.

Thanks to Carol Sakala at the Childbirth Connection for sending me those...

33 comments:

Amy Tuteur, MD said...

"Contrast that study with another from Obstetrics & Gynecology"

What do you mean contrast that study with the other? They are about two entirely different groups of women.

To be included in the 2008 study, a woman had to have had a previous successful VBAC and had to be a candidate for a repeat VBAC. The study from 2006 looked at women who had primary and repeat C-sections for all possible reasons. The groups were not comparable in any way:

In the 2008 study, 100% of the women had already had a successful VBAC. In the 2006 study it appears that 0% of the women had had a previous successful VBAC.

In the 2008 study, 100% of the women were candidates for attempted VBAC. In the 2006 study, less than 79% of the women were candidates for attempted VBAC. Almost 20% of the women were having PRIMARY C-sections for obstetrical indications like placenta previa.

The two groups of women are not comparable in any way. If you wanted to have a valid comparison group for the women in the 2008 study, you'd need women who had had at least 1 previous successful VBAC, were eligible for a repeat attempted VBAC, but chose C-section instead. It was extremely disingenuous (at best) for Carol Sakala to have suggested the comparison.

Tina Cassidy said...

Dr. Amy, I am just curious: Why don't you practice medicine anymore?

CNH said...

I linked in my blog, thank you! :)

Amy Tuteur, MD said...

I've written about my reasons on my blog and I will share them again, but first I want to make sure of something.

It is very important to me that you understand why the two studies cannot be compared directly. I'm sure you know that the first rule of scientific comparisons is that you must compare like with like. Do you see why these two groups are entirely different?

Moreover, do you see how misinformation gets propagated within the homebirth community? Carol Sakala suggested to you that you publish her entirely disingenous (at best) analysis of the papers, which she knows (or should know) is false. Now CNH is going to link to this post that provides only misinformation

Could you please change the post to reflect the truth, not the self-serving misinformation of homebirth advocates?

Mama to Monkeys said...

Please do not cave into "Dr." Amy's requests. We all know that she has a propensity for seeing things in her own special kind of way...no need to stoop to her level of spinning...uh, I mean "reasoning".

Keep up the great writing.

mamaofquiteafew said...

Ummm... Maybe I'm wrong, but in the methods posted here it says women with one or more lower transverse cesarean deliveries were included in the study. It also lists success rates for women with 0 prior VBACs. Would that indicate that it included women on their first VBAC TOL?

Thank you for posting this, Tina! Exciting! Others will twist it to suit their pre-existing positions, but I think all around it's good news for WOMEN! Especially in our cesarean-happy society, in which many women find themselves thrust into post-cesarean birth decision-making.

Amy Tuteur, MD said...

mamaofquiteafew:

"Would that indicate that it included women on their first VBAC TOL?"

Yes, it does. In the 2008 study, 33% of the women had had a prior successful VBAC, not 100% as I erroneously claimed.

Let's look at the results of the study in more detail. Here is how the authors describe the current study:

"The relationships between the number of prior VBACs and the probability of successful VBAC attempt or uterine rupture in the current pregnancy remain to be clearly elucidated. It is also unknown if successive labors will place an additive strain on the
uterine scar, increasing the risk of uterine rupture when VBAC is attempted. The purpose of this analysis is to evaluate the impact of increasing number of prior VBACs on the likelihood of VBAC success and uterine rupture in subsequent pregnancies."

Here are the main findings of the study:

"The frequency of VBAC success rose with increasing number of prior VBACs, increasing from 63.3% with no prior VBAC to 87.6% and 90.9% for those with one or two or more prior VBACs, respectively. The frequency of uterine rupture declined from 0.87% with no prior VBACs to 0.45% and 0.43% for those with one or two or more prior VBACs, respectively."

When uterine rupture did occur, the consequences were dire. There were 78 uterine ruptures in the group that had never had a successful VBAC, resulting in the deaths of 58 babies and 2 maternal deaths. In addition, there were 15 babies who lived but suffered permanent brain damage, and 21 women required hysterectomy.

There were additional ruptures and deaths in the groups of women who had had previous successful VBACs. There were 24 additional babies who died and no maternal deaths.

The 2006 study did not look at neonatal outcomes. The maternal outcomes for women having their second or higher C-section included maternal death 0.07%, and a hysterectomy rate of 0.42% for second C-sections, 0.9% for third C-sections, and 2.41% for third C-sections.

If you look at women in the 2008 study who attempted VBAC and had never had a previous successful VBAC, the rate of hysterectomy was 0.64% and the rate of maternal death was 0.02%. In contrast, in the 2006 study, when women with one prior C-section chose elective repeat C-section, the rate of hysterectomy was 0.42% and the rate of maternal death was 0.07%. Without knowing what happened to the babies of the women who had elective repeat C-sections, it is impossible to draw any conclusions about the relative safety of attempted VBAC vs. elective repeat C-section.

The fact remains that the two studies cannot be compared directly, and it is false to claim that they show VBAC to be safer than repeat C-section. The primary risk of attempted VBAC is death of the baby, and that result was not even presented in the second study.

Tina Cassidy said...

Dr. Amy, my post uses the word "contrast" which means to highlight differences. The word "compare" means to show the similiaries. You are right that the studies are different. Different cohorts, different purposes, different time frames, different teams, different places. But I think you are not seeing the forest through the trees. My point is to show that on the one hand, when the medical community is pushing repeat cesareans, we need to head the study that says there can be serious complications for repeat cesareans. The other study -- BY CONTRAST - shows that once a woman has had a successful VBAC, future VBACs are quite safe. So if a woman is planning a large family, taking a close look at these studies would be very important. As for your disparaging remarks about Carol, she merely forwarded the study. I write what I want. When I want.

Amy Tuteur, MD said...

"My point is to show that on the one hand, when the medical community is pushing repeat cesareans, we need to heed the study that says there can be serious complications for repeat cesareans. The other study -- BY CONTRAST - shows that once a woman has had a successful VBAC, future VBACs are quite safe."

As it happens, the studies are done by the same group, and the most recent study mentions the first study. Moreover, this is the same group that published the landmark study in the New England Journal of Medicine, Maternal and Perinatal Outcomes Associated with a Trial of Labor after Prior Cesarean Delivery, which definitely showed that an attempted VBAC has a greater risk than a repeat C-section. They concluded: "A trial of labor after prior cesarean delivery is associated with a greater perinatal risk than is elective repeated cesarean delivery without labor, although absolute risks are low. This information is relevant for counseling women about their choices after a cesarean section."

The authors do NOT conclude that their work shows that repeated VBACs are safe in contrast to repeat C-sections. The authors believe that their study shows that once a woman has had a successful VBAC, she is in a different risk category and should be counselled differently than a woman who has never had a successful VBAC.

The post is titled "Repeated VBACs are safe; repeated cesareans are not". It does not matter whether you compare the studies or contrast them. They do not show that repeat VBACs are safe and repeat C-sections are not, and it is misleading to suggest otherwise. For babies, repeat C-sections are safer than VBACs and these studies do not change that fact.

mom said...

Could we move on? I'm sick of the stats. Doesn't mean anyone is doing it right 100% of the time!

starparticle said...

"They do not show that repeat VBACs are safe and repeat C-sections are not, and it is misleading to suggest otherwise. For babies, repeat C-sections are safer than VBACs and these studies do not change that fact."

One implication that you're skipping over is for families that are planning 3,4, or 5 children. Many of these women, when faced with a primary c-section and then the choice of VBAC or a second c-section for their subsequent baby, are never counseled that their risk of having more and more c-sections raises their risk with each section. Since the stats now show that subsequent VBACs are in fact safer and safer, families planning to have more than two children will need to be informed both when they have their primary c-section, and when they are advised to have more with their additional children.

Mama to Monkeys said...

Amen, Mom!

Susan said...

Dear Tina,

I am distressed by your headline.

""Repeated VBACs are safe; repeated cesareans are not"

It is a huge overstatemet of the implications of these studies, and misleading to women making birth choices.

I think it is reasonable to say that the 2008 study did conclude that the risk of uterine rupture decreased after having a successful VBAC. I don't think they said they are "safe". Safety is always relative. Safer than if you had never had a previous VBAC, yes, and that is great information to have when counseling women about choosing a VBAC vs repeat cesarean. If she has already had a successful VBAC her risks of uterine rupture diminish. If I am interpeting it correctly, her risks become even less with each successful VBAC. But not zero. Still, as one person pointed out, useful information for women contemplating large families.

The other study, concluded this, also VERY important to women planning large families- "Because serious maternal morbidity increases progressively with increasing number of cesarean deliveries, the number of intended pregnancies should be considered during counseling regarding elective repeat cesarean operation versus a trial of labor and when debating the merits of elective primary cesarean delivery"

I am not anti VBAC; I love helping moms have VBACs. I do believe the majority of VBAC research has shown that even though no one indicator of uterine rupture can always be counted on as the sentinel symptom of rupture the most common sign FIRST sign is fetal distress. Thus most hospitals do want continuous fetal monitoring, which, where I practice, and in every nursing textbook I have ever read, is best accomplished with a mother in any position BUT flat on her back because that position decreases uterine blood flow. ( I read that you chose homebirth because you don't want to lie flat on your back and if you had continuous monitoring you would have to lie flat on your back?) Boy, where I work the nurse would ask you to please NOT lie flat on your back. And we have telemetry so you can walk in labor and have the safety of the monitor. I urge you to do more research about how uterine rupture is detected and it's consequences.

Here is one reference but the part I think is most important regarding continuous monitoring is way in the middle

http://www.emedicine.com/med/TOPIC3746.HTM


Here is the relevant data:

The signs and symptoms of uterine rupture largely depend on the timing, site, and extent of the uterine defect. Uterine rupture at the site of a previous uterine scar is typically less violent and less dramatic than a spontaneous or traumatic rupture because the scar is relatively avascular.

The classic signs and symptoms of uterine rupture are as follows: fetal distress (as evidenced most often by pattern of abnormalities in fetal heart rate), diminished baseline uterine pressure, loss of uterine contractility, abdominal pain, recession of the presenting fetal part, hemorrhage, and shock. However, modern studies show that some of these signs and symptoms are rare and that many may not be reliably distinguished from their occurrences in other, benign obstetric circumstances (see Table 2).


Table 2. Conditions Associated With Uterine Rupture


Condition Total Cases Cases With Uterine Rupture Incidence in Patients With Uterine Rupture, % Years of Data Collection No. of Studies
Abnormal pattern in fetal heart rate 344 187 54 1973-2002 8
Prolonged deceleration in fetal heart rate or bradycardia 143 114 80 1983-2002 4
Uterine tachysystole* or hyperstimulation 30 12 40 1994-1999 2
Loss of intrauterine pressure or cessation of contractions 144 6 4 1973-1999 3
Abnormal labor or failure to progress 169 49 29 1983-1996 2
Abdominal pain 454 118 26 1931-2000 9
Vaginal bleeding 381 140 37 1931-2000 8
Shock 213 71 33 1931-1993 3

*Defined as > 6 contractions during 2 consecutive 10-minute periods of observation.

Prolonged, late, or recurrent variable decelerations or fetal bradycardias are often the first and only signs of uterine rupture. Bujold and Gauthier showed that abnormal patterns in fetal heart rate were the first manifestations of uterine rupture in 87% of patients.46 In a study by Leung et al, prolonged decelerations in fetal heart rate occurred in 79% of cases and was the most common finding associated with uterine rupture.54 Rodriguez et al found that fetal distress was the most common finding associated with uterine rupture, occurring in 78%.55 Overall, in 4 studies from 1983-2000, prolonged decelerations of fetal heart rate or bradycardias occurred in 114 (80%) of 143 cases of uterine rupture. In cases that involved the extrusion of the placenta and fetus into the abdominal cavity, prolonged decelerations in fetal heart rate occurred invariably


Just more information and I believe very important information for any pregnant woman contemplating a VBAC and choosing the safest place and type of monitoring for birth.

pinky said...

In order to be accurate, wouldn't you have to compare Vbacs with Repeat elective c-sections that are also good vbac candidate? If you have a sick mom to begin with, you have a higher incidence of complications.

Also many primips are having their first baby in their 30s and 40s. This coincides with the age of the first cardiac event coming at a younger age. So we now have a population on woman who are destined to have a cardiac event and who are stressing the cardiac system with childbirth for the first time.

It all gets so very complicated.

Tina Cassidy said...

Yes it is all quite complicated and the headline, as headlines are wont to do, oversimplified the matter. And here's to complicating it further: I have never heard of ANYONE who has had a c-section be counseled on how many children she wanted to have. And yes, repeat c-sections may be safer for the baby in dire situations, but perhaps not the mother.

Tina Cassidy said...

Susan, thanks for sending over that info on continuous monitoring. That is very helpful to have. How many hospitals would you say encourage women to be upright or walking during labor while hooked up to a monitor? How many hospitals have telemetric monitors? I think your hospital is a rare, but great, exception.

pinky said...

My hospital does Vbacs. We have telemetry. I encourage woman to walk around. They leave for 5 minutes to walk then come back and jump in the bed.

Maybe since the bed is the most prominent thing in the room, folks think that is where they should be.

Susan said...

Tina,

I know there are hospitals with more restrictive policies. But I have been a labor nurse for 20 years in a hospital that has always

-allowed mom just about as many support people in the room as will fit

-encouraged intermittant monitoring and walking in labor

-Neither pushes nor discourages epidurals..it is the mom's choice....not ours. I strongly believe there is nothing to make a mom feel bad about if she chooses an epidural. Labor does hurt. Our mother's are well informed of the cons/risks of epidurals and most choose them finding the pain relief well worth it.

-always done mother/baby recoveries where baby is in mom's arms most of the time. Only out of her arms for the weight, measurement, some of the assessment, and bath..and that is after breastfeeding at about one hour old, and I try to keep that as short as can be, and involve the family...with mom watching from bed, or sometimes, if she is ready to stand up, she walks over and helps and watches. For the past at least 12 years or so at least, baby doesn't go to the nursery AT ALL unless by request of mom. Well, now they go for weight at night, and parents are welcome to come, and PKU, and parents are welcome to come. We really strive to keep them together the whole stay if that is what they want ( and most do want that ).

You might be suprised that I once had a home birth. It was a lovely experience with two CNMs. I would never have another though given all I have seen. Mostly what I have seen is that time critical emergencies DO happen to low risk, uninterfered with births and that minutes count. Not only that, but lots of skilled help counts too. If you have seen what it takes to get a mom into the OR with a cord prolapse, how all hands on deck shaves the time it takes because everyone pitches in during an emergency ( never seen one after an AROM...only in one LOW risk mom)...how one team is getting the mom ready while another is preparing for the baby. If you have seen a baby be born completely unresponsive ( also I have seen this in an unmedicated birth ) and seen how many skilled people it takes to do a resuscitation well, and how experience matters at how well it is done. These things matter to the intact outcome of the baby. Something that time and skill affect tremendously.

Regarding VBACs- we did them prior to the ACOG change about OB and anesthesia immediately available. I believe it was a GOOD and SAFE change. For a short time we didn't "do" VBACs. To me this is always sort of an odd concept as the patient has a right to refuse anything, so she could just refuse surgery, however, who wants to give birth in an adversarial situation? The community and our doctors ( most are very pro vbac ) worked to change the policy and it was changed. We get women from surrounding communities coming to have VBACs with us. They have to have a saline lock, they have to have continuous monitoring, and OB and anesthesia have to be on campus during active labor. I think those are good rules.

Are we rare? Chris works on the other coast of the country and her hospital sounds pretty similar.

Regarding are OB's counseling women about VBAC with this newer research about placentation issues with successive C/S and a previous successful VBAC making the risk of uterine rupture less than it was before the successful VBAC. Yes, they are I have seen it. I went to a course in San Francisco where the first study placentation issues with previous C/S and what that might mean to the choices a mother is making who wants a large family was discussed. I would be suprised if the attendants were not using this information as they counsel women. I know they are here. However, there was a time, who knows you may have this in your book, when insurance companies were trying to FORCE Vbac on women. This I believe was mid eighties, it was the same time as women were pushed out of hospital because insurance would only cover 24 hours. Lots of very unhappy, frightened mothers. A VBAC should be forced on no one. Many women are very afraid of going through labor only to have another C/S. And the morbidity of planned C/S is lower than an unscheduled C/S in labor. So that should be the mother's choice. I am glad it is.

Thanks for listening. Have you had your HBAC already or is your story retrospective? I wish you well. I am fearful because you are well known, wrote a popular book, and may encourage other women to make similar choices. Some of those women won't be the lucky ones.

Tina Cassidy said...

One more question for Dr. Amy. Since you read the study so carefully, how many of the ruptures were associated with the use of Pitocin?

Amy Tuteur, MD said...

"how many of the ruptures were associated with the use of Pitocin?"

That question was not addressed in the 2008 study. However, this study is a subset of the data from the 2004 NEJM article that showed the increased risk of rupture and neonatal mortality and morbidity in attempted VBAC.

In that study, augmentation of labor or induction of labor doubled the risk of uterine rupture. The risk of uterine rupture in spontaneous labor was 0.4%.

A much more remarkable factor in uterine rupture was success of the attempted VBAC. Very few of the women who had successful VBACs had a uterine rupture. Failed VBAC led to a 22 fold increase in the risk of uterine rupture. Undoubtedly, this is related in part to the fact that a rupture often leads to fetal distress and an emergency C-section is performed in the middle of labor. However, it also suggests that rupture may be more likely to occur if the uterus is attempting to push through a baby that won't fit.

There is some evidence to suggest that women who had the original C-section for reasons other than cephalo-pelvic disproportion, such as breech or fetal distress, have a greater chance of successful vaginal delivery and a smaller risk of rupture during attempted VBAC.

It is very important for women to understand that while induction or augmentation increases the risk of uterine rupture, rupture can and does occur during spontaneous labor. During my training, I was taught that it was almost never appropriate to induce or augment labor in a woman with a prior C-section, and that's the rule I followed. I had a very high VBAC rate and fortunately, never experienced a uterine rupture among one of my patients. Of course, I always practiced in places with 24 hour OB and anesthesia coverage, so there were no restrictions at all on VBACs.

pinky said...

"I have never heard of ANYONE who has had a c-section be counseled on how many children she wanted to have."

Funny you should say that. We had a Woman come in for a primary elective C-section for possible macrosomia. The Doctor on Call spent 45 minutes in the room chatting with her. I asked him what he explained about consent.

He told me the Green Journal had an article about consent and C-sections. He discussed how many children she was planning to have. Explained Accreta, previa, miscarrige (from implanting on the scar, hysterectomy risk. He also discussed the usual surgery complications.

I asked him if he discussed possible respiratory distress with a C-section. He replied "no because she is in labor so that should negate the C-section without labor respiratory distress syndrome.

Of course, he also explained shoulder dystocia because that is what she is worried about.

So I think OBs are getting better about informed consent.

Lisa said...

fact VBACs are safer than repeat C-sections and better for mother and baby. Fact risk of uterine rupture and other complications increase with each C-section. I think the better wording for the title would have been safer than repeat C-sections, to avoid conflict from this doctor and the nurses. Still it is sad to see that an OBGYN is afraid of birth.

Marlene, CPM said...

?'s for Dr. Amy, or anyone else who knows the answers:
I was told (by several Drs) that scar tissue was stronger than the original tissue. If this is true, why does risk of rupture increase after a C/S instead of decrease?
I was also told most of the time, when a doc does a repeat C/S she trims the excess old scar tissue. SO shouldn't this keep the chance of rupture steady, no matter how many you have?
Please help me understand the process going on here, so I can then better sort out all the conflicting views I am hearing. Thanks
Marlene

Unknown said...

Isn't it all so complicated because birth, and life, is unpredictable? Is there actually possible to do enough studies to show, definitively, the absolute safest way for every individual woman in each of her individual pregnancies to give birth?
So what's wrong with making all the options safe as possible, giving women all the information, and letting them decide for themselves?

What is the point in vehemently opposing Home Birth After Cesarean, or any other choices regarding how a baby should be born, for that matter?

Unknown said...

I was also told most of the time, when a doc does a repeat C/S she trims the excess old scar tissue. SO shouldn't this keep the chance of rupture steady, no matter how many you have?

A study published in July 2006 in Obstetrics and Gynecology showed that the risk vbac after multiple (2,3, or 4) c-sections is not significantly higher than vbac after 1 c-section. This was the same data used in the 2004 NEJM article on uterine rupture during vabc attempts. It is really difficult to find vbac support when you have had more than 1 c-section though.

Jenci4 said...

C-sections are more dangerous for the infant each time too. The main point should be what is safer for all involved, and a vbac is safer for the baby and mother. I had two c-sections. The first because of a placenta previa, but the second was a planned one, and the doctors took my daughter too early. Due dates are only a guess by a doctor. Labor is important! Also, women who have vaginal births are at a lower risk of getting cancer in the reproductive organs.

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