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    Find out what other moms-to-be are asking. Join in the discussion with Henci Goer, whose expertise is determining what the research tells us best promotes safe, healthy birth. If you would like to contact Henci outside of the Ask Henci forum, send an email to Goersitemail@aol.com.

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    May 23
    2007

    bicornuate uterus and VBAC

    Archived User

    Hi Henci,

    Are there any studies on the risk of UR (or other complications) for a VBAC with a bicornuate uterus?  especially a VBA2C?

    Thanks so much!

    Christa Bartley

    www.birthnetwork.org

    Henci Goer

    Unfortunately, according to one review of the medical literature, you are at greater risk for the scar giving way:

    Lieberman E. Risk factors for uterine rupture during a trial of labor after cesarean. Clin Obstet Gynecol 2001;44(3):609-21.

    Lieberman cites a study of planned VBAC in 25 women with uteruses that were not the usual shape compared with 1,788 women with the usual upside-down pear shape. The scar gave way in 2 (8%) cases in women with bicornuate, unicornuate, didelphic, or septate uteruses versus 11 cases (0.6%)  in women with the usual shape.

    The latter percentage falls in the typical range for scar problems, but 8% is quite high. Still, you have 92% odds that the scar will not be a problem. I also have no details from the cited study. For example, were the women with unusual uterine shapes all given oxytocin to stimulate stronger contractions? That would increase their risk of scar rupture. And, of course, a third cesarean surgery is not risk free, so there are trade-offs to be considered in making your decision. If you do decide to plan a VBAC, you, more than the typical woman with prior cesareans, might be wise to have it in a hospital capable of handling an urgent cesarean 24/7.

    -- Henci

    Archived User
    I have a question regarding the reliability of this study when, in relation to the non-bicornuate uterus group, so few women with bcu were used - does this not skew the data?
    Henci Goer

    It does, and perhaps it was a statistical oddity like having five girls in a row, but 1 out of 13, which is the same odds as 2 out of 25, is a very different number from 1 out of 163, which is the same odds as 11 out of 1788. I think that more of a question is whether the varying uterine shapes that were lumped together in their case series have differing consequences for the scar. Unfortunately, it is unlikely that we will get better data because the condition is rare and no single institution or group of institutions is likely to have a reasonably large set of women with it who plan VBACs.

    -- Henci 

    Henci Goer

    So, having written the above, what should appear in my in box in International Cesarean Awareness Network's bimonthly newsletter but a link to a study of Mullerian anomalies and VBAC. Mullerian anomalies, BTW, refers to abnormal development of the embryonic tube that develops into the Fallopian tubes, uterus, and vagina. I spent an extremely frustrating half hour trying to get the actual study to no avail. Here, at least, is the citation and abstract from PubMed, but, of course, the devil is in the details. 

    -- Henci

    Am J Obstet Gynecol. 2007 Jun;196(6):537.e1-537.e11. Related Articles, <script language=JavaScript1.2></script> opUpMenu2_Set(Menu17547885);" target=_self>Links

    Trial of labor and vaginal birth after cesarean section in patients with uterine Müllerian anomalies: a population-based study.

    Erez O, Dukler D, Novack L, Rozen A, Zolotnik L, Bashiri A, Koifman A, Mazor M.

    Department of Obstetrics and Gynecology, Faculty of Health Sciences, Soroka Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.

    OBJECTIVE: The aim of our study was to determine the success rate of vaginal birth after cesarean section among patients with Müllerian anomalies in comparison to the success rate of vaginal birth after cesarean section in patients with normal uterus with emphasis on the rate of uterine rupture. STUDY DESIGN: A retrospective population-based study was designed, including all patients with a previous cesarean section that attempted vaginal birth after cesarean section during the study period. Women with known Müllerian anomalies were included in the study group. The control group consisted of women with normal uterus. The rates of vaginal birth after cesarean section, uterine rupture, maternal morbidity, and perinatal outcome were compared between the groups. RESULTS: Of 5571 eligible patients, 165 (2.96%) had Müllerian anomalies. The rate of vaginal birth after cesarean section was significantly lower among patients with Müllerian anomalies than in patients with normal uterus, 37.6% (62/165) vs 50.7% (2740/5406), respectively (P = .0009). During the study period, there were 10 cases of uterine rupture, all in patients with normal uterus. The major indication for repeated cesarean delivery among Müllerian anomalies patients was malpresentation, 58.3% (60/103) vs 14.4% (385/2666) in patients with normal uterus (P < .001). CONCLUSION: A trial of vaginal birth after cesarean section in patients with uterine Müllerian malformations and cephalic presentation is not associated with a higher rate of maternal morbidity and uterine rupture.

    PMID: 17547885 [PubMed - in process]

    Archived User

    Thank you, THANK you for posting this! I have a unicornuate uterus and I am having this discussion with my OB tomorrow. It is so hard to find information!

    Henci Goer

    You're welcome! I hope your OB was receptive to what you had to say.

    -- Henci

    Archived User

    I also have a septate uterus (a complete septum) and am also preparing to have a conversation with my OB about VBAC next week.  I am only 10 weeks pregnant, but I want to hear what my OB has to say adndecide if i need to find a new OB.  I had a previous pregnancy with no complications other than breech presentation, which was the cause for the c-section, because my OB at that time was not willing to attempt an inversion, because it was thought that there were amniotic bands present, which Inow think was a misdiagnosis based on seeing the septum and interpreting it wrong, since the septum wasn't noticed in the first pregnancy.  If I want to even consider trying for a VBAC, my OB requires that I sign a waiver taht says I understand a whole bunch of different things about the risks and benefits.  One of these is that risk of rupture is about 1% and that in the case of rupture the baby would likely die becasue they wouldn't be able to get it out in time.  is that true?  This waiver I'd have to sign has nothing to with the septate problem, only the VBAC thing and so I was wondering if you knew where that 1% number might have come from, since in my recent (haphazard and undirected) research it seems that it is not as high as that.  Also, I was wondering if, Since you posted the abstract, the entire article had turned up.  I'm confused adn frustrated, and I don't know who I can trust to giveme accurate information, and I don't trust my OB office.
    Thanks,

    Brandice

    Archived User

    I have uterus didelphys. I delivered my daughter last August at 39 weeks through C-section because she was breeched. She was in my right uterus.

    Now I am 14 weeks pregnant with another baby in the left uterus. I have switched to a high-risk maternal fetal medicine doctor, who has agreed to let me attempt a VBAC even if the baby is breeched.

    The hope is that when my first doctor did the C-section, she only cut into the right uterus, and that the left uterus is still intact. If she did cut into the left for whatever reason, my doctor has explained that because they do not know how the uterus's blood supply is, it may not have healed to its full potential and could be at greater risk for rupture. But we do not know!

    I have much hope, from reading the synopsis of that study, that I will not have any complications with the VBAC. I hope to do as much of a "natural birth" as possible in the hospital, but I do not want to be induced or given prostaglandins to progress the labor. I am hoping to have a hep/saline lock and that's it, with no epidural or pain relief - because if there were to be a rupture, I want to be able to say "Ow. Something just happened." (heh!)

    This is good hope. Thanks!

    Henci Goer

     

    Posted By on 05 Apr 2010 02:07 PM

    I also have a septate uterus (a complete septum) and am also preparing to have a conversation with my OB about VBAC next week.  I am only 10 weeks pregnant, but I want to hear what my OB has to say adndecide if i need to find a new OB.  I had a previous pregnancy with no complications other than breech presentation, which was the cause for the c-section, because my OB at that time was not willing to attempt an inversion, because it was thought that there were amniotic bands present, which Inow think was a misdiagnosis based on seeing the septum and interpreting it wrong, since the septum wasn't noticed in the first pregnancy.  If I want to even consider trying for a VBAC, my OB requires that I sign a waiver taht says I understand a whole bunch of different things about the risks and benefits.  One of these is that risk of rupture is about 1% and that in the case of rupture the baby would likely die becasue they wouldn't be able to get it out in time.  is that true?  This waiver I'd have to sign has nothing to with the septate problem, only the VBAC thing and so I was wondering if you knew where that 1% number might have come from, since in my recent (haphazard and undirected) research it seems that it is not as high as that.  Also, I was wondering if, Since you posted the abstract, the entire article had turned up.  I'm confused adn frustrated, and I don't know who I can trust to giveme accurate information, and I don't trust my OB office.
    Thanks,

    Brandice



    Let me start with the general VBAC info you have been given. With proper care during labor, the odds of the scar giving way can be about half what you have been quoted, that is, 0.5%, or 5 per 1000, not 1% or 10 per 1000, and few babies die as a result of scar rupture, although a repeat c/sec will be needed. A large U.S. study reported a scar rupture rate of 4 per 1000 with spontaneous labor (labor started on its own and no oxytocin to stimulate stronger contractions once labor began) and that in the whole population having VBAC labors, 1 in 10,000 babies died as a result of scar rupture, although other studies have reported rates somewhat higher. In fact, according to another study of that same population, the odds of your dying as a result of an elective repeat c/sec, that is, a c/sec with no medical indication, are in the same range.

     

    Now for the bad news. Many obs are not doing VBACs at all, even with women who are ideal candidates, and some string women along--there is no kinder word for this--by telling them that they will do VBACs at the beginning of pregnancy but become more and more negative as the pregnancy continues, and if they can't scare the woman away from it, they finally tell her they won't do a VBAC too late for her to change doctors. I would take it as a bad sign that at 10 wks you are already being warned off VBAC. Add on top of that your not being an ideal candidate, and I would be surprised if you got a favorable response from your ob on VBAC.

    You say you don't trust your ob. I think your best bet is to find an ob you can trust. Ask around your community to find an ob who is enthusiastic about VBAC. The doulas and midwives often know who this is, or there may be a birth resource center, birth network group, or ICAN chapter in your community who can help you find the go-to gal or guy. The judgment of an ob who generally encourages VBAC can be trusted if in your case he or she does not recommend VBAC.

    -- Henci

    Henci Goer
    Posted By on 09 Apr 2010 03:07 PM

    I have uterus didelphys. I delivered my daughter last August at 39 weeks through C-section because she was breeched. She was in my right uterus.

    Now I am 14 weeks pregnant with another baby in the left uterus. I have switched to a high-risk maternal fetal medicine doctor, who has agreed to let me attempt a VBAC even if the baby is breeched.

    The hope is that when my first doctor did the C-section, she only cut into the right uterus, and that the left uterus is still intact. If she did cut into the left for whatever reason, my doctor has explained that because they do not know how the uterus's blood supply is, it may not have healed to its full potential and could be at greater risk for rupture. But we do not know!

    I have much hope, from reading the synopsis of that study, that I will not have any complications with the VBAC. I hope to do as much of a "natural birth" as possible in the hospital, but I do not want to be induced or given prostaglandins to progress the labor. I am hoping to have a hep/saline lock and that's it, with no epidural or pain relief - because if there were to be a rupture, I want to be able to say "Ow. Something just happened." (heh!)

    This is good hope. Thanks!



    I would think that you would be able to get the information you need from the surgical records of your last delivery, and if not, your prior ob might remember since your prior delivery was fairly recent and yours was an unusual case. I hope that all works out as you would wish.

    -- Henci

    Archived User

    Thank you, Thank you.  I think you're right, I think i do need to look for another Dr.  I do have another question though, since my septate uterus was undiscovered last time, I don't actually know which side the last pregnancy was on.  Is there any good way to determine this afte the fact (other than that i remember feelingher more on my left than my right- is that reliable?) and is this relevant to the liklihood of rupture?  if i figure out that my last pregnancy was on the oposite side than this time, does that mean my risk of rupture is lower, since the portion of uterus with scar tssue will not be pushing?

    Thanks

    Brandice

    Archived User

    Though this is about VBAC vs ERCD generally and not about people with uterine abnormalities, I just wanted to link to it in case anyone else trying to decide between the 2 might find it useful.

    http://consensus.nih.gov/2010/vbacstatement.htm

    Henci Goer
    Posted By on 19 Apr 2010 11:34 AM

    Thank you, Thank you.  I think you're right, I think i do need to look for another Dr.  I do have another question though, since my septate uterus was undiscovered last time, I don't actually know which side the last pregnancy was on.  Is there any good way to determine this afte the fact (other than that i remember feelingher more on my left than my right- is that reliable?) and is this relevant to the liklihood of rupture?  if i figure out that my last pregnancy was on the oposite side than this time, does that mean my risk of rupture is lower, since the portion of uterus with scar tssue will not be pushing?

    Thanks

    Brandice


    As I wrote another poster on this topic in this same thread, the information on which side the prior pregnancy was on might be in your surgical records. As for your thought that you would be at lower risk for scar problems if the pregnancy is on the intact side, I would think that an ultrasound scan could tell you and your (hopefully new) care provider where the scar is in relation to where the baby is in this pregnancy.

    -- Henci

    Archived User

    I have a BU and have had a CS.  My son was born at 35 weeks.  My water broke and I was in labor for about thirty hours and wouldn't budge passed 2cm, so they had to do a CS.  Q: Is there an increased risk of having an early delivery with another pregnancy, would I be able to do a vbac, and what exactly are the risks to the baby if their is a UR during labor?  My dr wont really talk about it.

    thank you,

    eryn

    Henci Goer

    I'm afraid that I haven't researched the effect of a bicornate uterus on length of pregnancy or labor. What I can tell you is the risk of scar rupture in a VBAC labor based on what little data we have. I have two studies of VBAC in women with uterine anomalies, one of 25 women (Ravasia 1999) and one of 103 women (Erez 2007). The bigger study reported no scar ruptures while the smaller study reported 2, both in women who had been induced. Induction of labor is known to increase risk of scar rupture. Leaving the question of induction predisposing to scar rupture aside, the overall rate in the two studies combined is 2/128 = 1.6%. This is higher than what the rate can (and should) be in a woman without a complication predisposing to scar rupture, which is 0.5%. Still, looked at another way, there is a 98% chance the scar will be just fine and possibly higher, since the women whose scars gave way had been induced.

    As to what happens to the baby if it does give way, according to the latest data, a huge review of the research that underpinned a National Institutes of Health conference in the spring of last year (Guise 2010), the likelihood that you will lose the baby in the case of scar rupture is 6% provided you are in an environment where staff can respond promptly. To find out the risk of losing the baby to scar rupture as a result of planning a VBAC, multiply 1.6% (the odds of scar rupture) by 6% (the odds of mortality) and you get 0.1% or 1 perinatal death per 1000 VBAC labors in a woman with an abnormally shaped uterus due to scar rupture. There is also a risk that the baby will survive but be brain injured. This risk, too, is very small. I should add as well that maternal complications are more likely in a VBAC labor that ends in cesarean than in a planned cesarean.  Against that risk you must weigh the risks of accumulating cesarean scars for you and any future babies. These include increasing risk of placenta previa (placenta partially or completely covers the cervix) and placenta accreta (the placenta grows through the uterine lining into the underlying muscle and sometimes even through the uterus), both of which pose serious threats to you and the future baby, as well as the likelihood of your forming dense adhesions, internal scar tissue that can cause chronic pain and make any future surgeries more difficult and more likely to result in surgical injury to internal organs or blood vessels.

    The missing piece in this calculation is how likely a VBAC would be to end in a vaginal birth? Without that information, you can't decide whether the risks attached to planned VBAC or elective repeat cesarean are more acceptable to you. All of this is irrelevant, though, if your ob won't talk to you about it. Maybe the first step is to find one who will.

    ~ Henci   

    Archived User

    I have been doing research on VBAC options for the bicornuate uterus situation. I did not know in my first pregnancy that I had a bicornuate uterus until the emergecy c-section at 9cm. My water broke right away before my labor really progressed....so they gave me no choice but to be induced. Neither my body nor my son's like the induction and he went into fetal distress and we had an emergecy c-section at 9cm. I can't find enough information on bicornuate uterus vbacs let alone for those who are more prone to water breaking at beginning of labor. Do you have any thoughts on this issue. The more I read the more likely  it looks like I might not be a good candidate for VBAC...but i'm still researching. I am only 15 weeks and have some time to think about this further.

    Thanks!

    Henci Goer

    Beyond what is written in this thread, I don't have anything that might help guide you, other than to say that I don't know that having had your bag of waters break makes you prone to repeat that with the next labor.

    If you are interested in VBAC but want to take a conservative approach, your best bet would be to find a patient, supportive care provider who tries to avoid induction and labor augmentation (using IV oxytocin to strengthen labor), but when it is necessary, does so with an oxytocin protocol that "starts low and goes slow." That approach results in equally high vaginal birth rates with much less instance of uterine hyperstimulation and abnormal fetal heart rate and will keep risk of scar rupture low. Your story hints that one possible explanation for the fetal distress that led to your cesarean was that this approach was not used last time. Furthermore, if membranes do rupture, the vast majority of women will begin labor spontaneously within 24 hr. It is safe to wait that long, especially if nothing is inserted into the vagina (tampons, vaginal exams, internal monitoring, cervical ripening techniques). According to a review of trials of early induction versus expectant management, newborn infection rates were not increased and maternal infection rates were only slightly increased with expectant management--and those studies were done before group B strep antibiotic prophylaxis was routine and in women having multiple vaginal exams and possibly cervical ripening and internal monitoring. Unfortunately, with so few practitioners attending VBACs at all, it is likely to be hard to find such a person. 

    If you decide to plan repeat cesarean, this page on the International Cesarean Awareness Network's website can help you plan one that is family centered.   

    ~ Henci


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