Thursday, 26 August 2010

Vbac with a mullerian anomaly

Following on from this post I just thought I'd post a bit of the research I have been finding and reading. I hope it helps someone. Please note if you have a normal uterus you may want to stop reading now as this probably will be rather dull, unless you are particularly interested in dodgy double uteri.

Realistically speaking there aren't any answers I suppose, statistics are never answers. I have found two studies, one of which Sacred and scarred has posted here and the other of which is here and there is a tiny bit more detail here Unfortunately that seems to be all the research I can find, and it has no specifics for the different types of anomaly, but the study groups are very small anyway.

I'll copy and paste the relevant bits though to stop you having to sift through it all.

Firstly I guess the bit you may be interested in are the outcomes

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)
So much lower vbac rates among people with mullerian anomalies, however
The major indication for repeated cesarean delivery among Müllerian anomalies patients was malpresentation
So it was mainly due to the fact that babies are more likely to be breech. Of people that attempted a vbac so presumably weren't presenting as breech
The cesarean delivery rates were 20% (5/25) and 25.1% (448/1788)(this is the normal uterus group), respectively
So if you are presenting normally and get chance to vbac there is a good chance you may acheive one. However as I'm sure you know you are much more likely to be malpresenting with a dodgy womb then you are with a normal womb.

However in vbac one of the main things to conside is the risk of uterine rupture.

There were 1813 attempts at vaginal birth after cesarean delivery between 1992 and 1997 at the Foothills Hospital in Calgary, Alberta, Canada. Of the patients 25 had known müllerian duct anomalies and 1788 did not

The rates of uterine rupture were 8% (2/25) in the group with müllerian duct anomalies and 0.61% (11/1788) in the group without müllerian duct anomalies

8% sounds very high, however note the bit in bold

The authors studied five years records in Calgary and found 25 such women who had tried for vaginal deliveries after a previous caesarean. Two of them suffered a ruptured uterus (8%) but both had been induced with prostaglandin gel, and one had had oxytocin as well. Although the rate of rupture was only 0.61% in the 1800 women with apparently normal uteri, the authors do not say how many had had prostaglandin or oxytocin and whether that added to their risk.

In contrast the other article comes to the conclusion that

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

It's hard to tell really whether vbac with a dodgy uterus is more likely to end in a rupture, but it seems fair to say that being induced vastly increases the rate of rupture. Induction does increase the rate of rupture with normal uteri too, but to nowhere near the same extent.

This is the bit which I personally find most relevant though
All cesarean deliveries among women with müllerian duct anomalies were performed urgently in response to severe fetal heart rate abnormalities. The rates of fetal heart rate abnormalities necessitating immediate delivery (60% vs 14.1%, P =.013), operative vaginal delivery (40% vs 19.6%, P =.02), and cord prolapse (8% vs 0.45%, P =.0076) were significantly greater in the group with müllerian duct anomalies.

My DS was born by section due to his heart rate falling a lot. This is something I hadn't considered, I just presumed it was one of those things and hadn't considered it could be due to my uterus shape. I feel this is something I'll have to research a bit more.

I guess the conclusion that I have reached is that as long as you aren't carrying breech you are just as likely to get a normal birth after a caesarian as anyone else, but when things do go wrong they are much likely to go badly wrong. I think the thing is to do what feels right to you, and not what you think others think you should do. Statisitics and other peoples stories never tell your story.


SarahR said...

I have an arcuate uterus which wasn't diagnosed until my second section ! This does make interesting reading x

Bernardeena said...

Did the reasons for your sections turn out to be anything to do with your uterus shape? Arcuate is just slightly off normal isn't it, just a slight curve in at the top? I find it all quite interesting and fascinating, but I'm never sure if everyone else will just find it incredibly dull.

SarahR said...

I have more of a heart shape according to the consultant who had a good rummage around ! I've had two sections now and the first wasn't, but they can't say for certain that my second (premature delivery) wasn't due to the abnormality. I have also had a miscarriage which can be due to these abnormalities too - but again this was before mine was diagnosed and they won't comment as to whether it was significant or not.

K77 said...

I've been mulling this over for a long time now. Honestly, I think that if a women with an MA tried for a HBAC with an independent midwife that would be her best bet.

Just look at the rate of rupture with induction. What other interventions are being done as well? Continuous monitoring would be restrictive, poor positions during 1st and 2nd stage, refusal of hospitals to assist with vaginal breech births etc.

Of course rupture can happen, but I'd say it's extremely rare when birthing women are not interfered with by the medical establishment.

I was talking recently with a friend who is almost a midwife (still a student). She was saying how at some points during labour it is perfectly normal for the heartrate to drop, and that this is often cause for panic/c-section in hospitals. It made me wonder.

Something else to consider would be whether you had double layer suturing with your c/s. I asked for it with mine, but I do want to get my records and check.

Bernardeena said...

Induction was the one thing I was always going to refuse anyway, but just having researched it a bit more it has definitely confirmed what I was thinking. They don't generally induce here until you are 12 days late anyway, and hopefully he will be here before that anyway.

I know my midwife was saying the heartrate often drops in labour, but Noah's heartrate was consistantly dropping to the 50's, I think I was contracting on his cord. I just know that as we were leaving the theatre one of the doctors said to my DH that it was a very good job we came in when we did, but they did also say I could try vbac as his birth was just one of those things.

Sarah that sounds more like a bicornuate then an arcuate uterus. I suppose the problem withh miscarriage is they don't know normally if it was caused by the uterus shape or if it was just one of those things. I know I have wondered before whether mine was related to my uterus or now. I can't believe they just didn't notice at your first section though?!!