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Another VBAC question

(12 Posts)
hopsalong Mon 10-Apr-17 08:13:28

I know this topic has been covered to some extent, but I wanted to ask specifically: has anyone who had a previous large baby, and who seemed to be having another one (predicted to be 4.5kg + by 40 weeks) been encouraged/ discouraged by their hospital from a VBAC? I have been getting somewhat contradictory advice. On the one hand, midwife still very gung-ho, but obstetrician said that "on balance" she recommended an elective c-section at 39 weeks.

The data point that's making me brick myself (I would actually prefer a VBAC) is that the risk of scar rupture goes up from 1/200 (already seems pretty high) to 1/30 or so with a weight over 4kg (according to hospital statistics on handout). I know there will be plenty of women who managed just fine to VBAC very large babies, but I'm wondering how people factored estimated weight into their decision process?

OP’s posts: |
EveMoneypenny Mon 10-Apr-17 09:44:42

Sorry, no advice, but will be following this with interest. My first baby was a massive 5.24 kg. I'm only 12 weeks pregnant, but I know ideally I'd like a VBAC.

Your stats on scar rupture with a 4kg+ baby are certainly food for thought. It would be interesting to know how many of those involved a baby that was bigger than the baby delivered by cs and so the uterus is stretched beyond the point it previously reached. I'm sure I've read that you are at an increased risk of rupture if your first cs was premature, which makes sense. I wonder if there are any studies on this.

hopsalong Mon 10-Apr-17 10:42:38

Wow! That is massive! My first was "only" 4.35kg but with a big head, and this one is predicted to be bigger (I know I know to take scans with a grain of salt). The problem seems to be that the longer you leave it the bigger they will get. So I feel that if I went into labour this week at 37 weeks I might have a good chance naturally, but by 41 + 10 (they will book a c-section then anyway if vaginal birth hasn't happened) I feel it has to be less likely. Midwife in fact said that they would only allow this long for a VBAC because I am tall: are you?

Did you have gestational diabetes or any other factors (massive husband?!) that might explain such a big baby? I haven't got any factors to explain having a larger than average baby (though nothing compared to yours!). But maybe you will find this one is a lot smaller naturally, e.g. if different sex, or just because of chance (not many babies born at that weight!)

OP’s posts: |
size16 Mon 10-Apr-17 11:50:48

op i'm surprised how rude your last post is considering you've had a big baby yourself

KP86 Mon 10-Apr-17 11:55:49

Not sure I see how OP was rude?

DoctorMonty Mon 10-Apr-17 12:46:49

Hopsalong, can you tell us a bit more? Was your caesarean your first, and why was it a caesarean?

By far the strongest predictor of a successful VBAC is a previous normal vaginal delivery.

So, if you've had other VDs and/or your caesarean was for something like breech, or for some unknown reason the baby suddenly got distressed etc, then you have getting on for 90% chance of success, and I wouldn't worry too much about a bigger baby.
If however you've only had that one delivery, particularly if your CS was for failure to progress, then you're edging closer to 50-60%. I don't know what your BMI is but if it's over 30, that's also a risk factor for unsuccessful VBAC. And adding in a big baby too makes the odds even slimmer... hmm

hopsalong Mon 10-Apr-17 12:58:46

How was I rude? Certainly didn't intend to be!

DoctorMonty: thanks for asking. I'm afraid it doesn't look all that good for me. I'm tall and slim (BMI under 20 before pregnancy), have gained a normal amount of weight (just under two stone), and don't have gestational diabetes. But I haven't had a vaginal delivery and the surgeon who performed the last c-section wrote that it was due to cephalopelvic disproportion in my notes. The current baby was estimated to weight 8lbs at 36+0, and the biparietal diameter was already over 10cm. So am thinking it isn't looking promising... But I went overdue last time (and then induction got nowehere -- I tried gentler things but refused drip when consultant told me I would have a 60% chance of a c-section anyway). So I was hoping that if I go into labour naturally this time I would have a shot?

OP’s posts: |
EveMoneypenny Mon 10-Apr-17 16:24:38

I don't think hopsalong was rude at all! He was truly massive, no point pretending otherwise.

I am quite tall, as is my husband, and went to 42 weeks last time before induction. My cs was also because he was in a bad position - back-to-back, as well as big. I don't think i had gestational diabetes but I wasn't offered the GTT last time (obviously will be this time!) My BMI was overweight last time and I definitely put a bit too much weight on. My BMI is a little less now, just above 25, and I am going to try very hard to keep my weight gain at a sensible level. Of course that could all be in vain - perhaps I just grow big babies! Good luck with your decision.

DoctorMonty Mon 10-Apr-17 19:35:24

Yeah... I think you've got your answer there! True CPD is pretty rare, but with babies as big as you grow them...

I don't suppose there's much harm in just booking your section at 41/40 rather than 39/40, in case if all happens spontaneously. But they wouldn't put you on the drip if things didn't move along nicely (sounds like you wouldn't want if anyway) so it's whether you want to go through however many hours of labour for probably around 50:50 chance of needing a section anyway, plus the risk of scar dehiscence/rupture, plus it being an emergency not an elective. I think you can sense which I'd go for wink

TippetyTapWriter Mon 10-Apr-17 19:37:02

Following with interest... hadn't heard that stat about size. My ds was born at 39 weeks by elcs because he was breech. He was 3.96kg at 39 weeks so following the curve would have been over 4kg at 40 weeks and 4.5kg at 42 weeks. What worries me more is that his head was enormous, well over 100th centile at birth and they were actually concerned he had hydrocephaly! Luckily he didn't. Plus all his weight was width as he wasn't long. First midwife described him as 'hefty' and my mum said he was built like a heavyweight boxer... !! Had enormous broad shoulders and back.

I know all babies are different but this one has measured ahead at two scans so might end up being another big one.

I would prefer vbac as my elcs experience was actually quite bad. Ds was born with breathing difficulties and suspected sepsis and admitted to nicu for a week. I know breathing complications are a rare complication of cs but I don't want to repeat the experience of having to go home without my baby sad But I know there's no guarantee I won't end up with emcs or bad vbac. Wish I had a time machine so I could check what was going to happen.

smellsofelderberries Wed 12-Apr-17 13:16:27

I don't have any experience of VBACs but I look into the research of pelvic floor trauma sustained during VBACs. It can be quite common, particularly with babies that have massive heads. It's something people don't talk about and that needs to change.

TippetyTapWriter Thu 13-Apr-17 08:55:45

Do you have any more info on that elder?

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