Wednesday, 15 August 2012

Decisions. Part 1 - Show Me The Stats!

I have a decision to make.

Suddenly I am 26 weeks pregnant (ok I should have seen that coming I know) and it's looking increasingly unlikely that my preferred method of birth (neonatal teleportation) is going to be an option.

So, I have to decide - repeat C-section or VBAC*?

There are a huge number of things to consider physically, emotionally and practically in this but I'm trying to remind myself that childbirth is, at worst, a few days. What comes after, the child, is the rest of my life and his/hers too. With that in mind, safety has to be the trump card.

Recent studies have shown that repeat cesareans are slightly safer than VBACs for both mother and baby, but the risks are so small in both scenarios that you may as well start worrying about being killed in a car crash on the way to hospital. Emergency cesareans are considerably more risky.

So, before I just go for the planned c-section, I want to know this - how likely it is that an attempted VBAC, would end in another emergency trip to theatre?

Billions of women have given birth, millions have had c-sections in modern hospitals, with scientifically trained doctors, and gone on to have more children - we should have the stats on this right?

Well, I'm hoping someone reading this can tell me I'm wrong, but it seems like the answer is no.

When I put the question to my obstetrician he gave me the standard figure - 70% of VBAC attempts result in a vaginal birth. But when I started to dig a bit, there were no more answers.

The thing is, 70% seems a little, well, vague. There are a huge number of reasons for that initial cesarean; a planned c-section for a breach baby, a terrified dash to theatre because the foetal heart rate suggests the baby is in distress etc. etc. What I want to know is - what is the chance of success in my specific situation?

Does the fact that I got to 10cm dilated (all be it with chemical assistance) mean I am more likely to give birth vaginally this time than, say, someone who's previous labour never got going after a failed induction? Or does the fact that my last baby was physically stuck in my pelvis mean my chance of success with a second is less than someone who may well have popped the sprog out easily had they only got the chance?

When you start asking about the specifics, 70% is utterly meaningless. Perhaps 90% of women who had the same problems as me succeed in giving birth vaginally next time or maybe its only 5%. I've plucked those figures from the air but either is possible if there were enough women in other groups whos success/failure rates are different.. 

You wouldn't need elaborate experiments to answer these questions, just someone to keep good records of lots of births and then crunch the numbers.  I spend my working life with scientists who study the tiniest actions of genes and molecules that may or may not  influence rare human diseases. It is exquisitely precise, detailed, study into things so tiny no human could ever see them, the interactions and variables are mind boggling but it's work actual humans can do. Surely we should be able to answer a simple question about getting 8lbs of baby out of a space hopper sized womb?

I need to make the decision in 10 weeks time. What do you think my chances are that a study will suddenly emerge that answers my questions by then?

Perhaps I should just keep hoping for teleportation.


*VBAC - Vaginal Birth After Caesarian


  1. So you rejected the koi assisted option, then?

    1. Ah yes the koi! Of course, how could I have forgotten that? problem solved! Thanks Helen!

  2. As you know, I've been there before with the whole VBAC / C-section debate. I hope you make the decision that is right for you with no pressure. Thanks for submitting this for the Britmums Carnival x