Fetal macrosomia and VBAC?

[feminist~mama]

I'm looking for studies regarding big ol' babies and VBACs... I've been seeing a midwife and yesterday did my obligatory appointment with an OB. Naturally, he was all about "you're already measuring large" and "we'll offer an ultrasound at 38-39 weeks and then a repeat section if there's thought that this is a large baby".

I talked to my partner about it who was a bit freaked out (sigh) and would love some actual studies that talk about the risks of uterine rupture during a VBAC with a big baby. I think it would make him feel better.

My DD was 10lbs, 8.5oz, with no gestational diabetes, so I do have a history of making a pretty large baby. I *do* have a different baby daddy this time, so hopefully I don't have anything to worry about! *Fingers crossed*

[cathicog]

to some practitioners, anything over 9 lbs is large. Babies move and heads mold, pelvises are not made out of concrete,they come apart and go back together, and the movements of the mama on her feet, or on hands and knees, can get even a 12lber out just fine...if you're 35 weeks now, let's say, and the baby is approximately 7 lbs now, might be about 9 by birth....that's quite doable, it sounds like...

[AlexisT]

ACOG says you can "consider" prophylactic section at 5kg, 4.5kg for diabetics. That doesn't mean you have to, but ACOG is pretty much about erring on the side of caution, so if even they don't say to section for a 10 lb'er, I wouldn't (absent any other considerations).

I don't have any studies--I have heard that smaller babies are more likely to result in a successful VBAC but 1) you'd expect to see some effect and 2) doctors behave differently when they know the baby is big, and you can't correct for that.

[thorn]

there's a really great thread on the atlanta ican message board about this. you have to join to read it, but I can't copy/paste it all here due to mothering's copyright issues I think.

http://atlanta.ican-online.org/board...p?topic=3470.0

[AustinMom]

Here are a few links....
http://www.ncbi.nlm.nih.gov/pubmed/2...?dopt=Abstract
http://www.springerlink.com/content/r3445h7836303110/
http://www.aafp.org/afp/2001/0115/p302.html
http://www.drplace.com/ACOG_Issues_G...s.16.27195.htm
http://www.birthtruth.org/fears.htm
http://www.gentlebirth.org/archives/icanvbac.html

Most of these are all highly esteemed (in the OB world most of all) medical organizations. They all say that doing a ERCS or just an elective c/s is not recommended, neither is induction. Basically, there is no way of knowing whether a baby is truly macrosomic or not, and u/s is not a better analysis of diagnosis this.

The main thing care providers are scared of, it seems, is shoulder dystocia. This can be avoided by not birthing on your back, and can be fixed by simple position changes at the point of discovery. With an epidural, these may be harder.

It seems like almost every woman now days measures large. This could be because the average birth weight of babies has gone down, and this is in part due to ECS and inductions before baby is done "cooking", so they come out smaller. You ask a MW what her average weight of a baby is, and an OB, and I'm sure the OB's will be much higher.

Personally, I would never choose ERCS. My son was 9lb 8oz and was a cs due to "failure to progress" and asynclitism, and we are HBACing with our second in Sept. Your body is not going to grow a baby too big for you to birth unless there is another factor like GD, rickets, etc. It's against our animalistic survival mode. Your body knows what it can handle, and your body is the one growing the baby, so it would be illogical for the two to not match up. Some women just grow bigger babies than 7lbers. We must be two of those women

[MNHall]

I'm sorry I don't have the stats to give to you....but, I have personally heard and read a number of stories of women who had a c/s for a baby that was "too big", measuring maybe upper 8 or lower 9 pounds...but then went on to deliver a 10 plus pound baby via VBAC! So...those kind of stories really show that weight does not determine vaginally delivery success!!!

I know I personally LOVE having u/s's! I just find it so bonding to see my little one on the screen! And for me personally, it's reassuring to check in. But, in this case, if a measurement of your baby is the only reason, maybe saying no thank you will give your doctor less pull of the "big baby" card!

I hope someone can provide you with some stats about big babies and vbacs!

Good luck!

[feminist~mama]

Originally Posted by AustinMom

Here are a few links....
http://www.ncbi.nlm.nih.gov/pubmed/2...?dopt=Abstract
http://www.springerlink.com/content/r3445h7836303110/
http://www.aafp.org/afp/2001/0115/p302.html
http://www.drplace.com/ACOG_Issues_G...s.16.27195.htm
http://www.birthtruth.org/fears.htm
http://www.gentlebirth.org/archives/icanvbac.html

Most of these are all highly esteemed (in the OB world most of all) medical organizations. They all say that doing a ERCS or just an elective c/s is not recommended, neither is induction. Basically, there is no way of knowing whether a baby is truly macrosomic or not, and u/s is not a better analysis of diagnosis this.

Thanks so much! This is exactly what I was looking for!

And thanks for all the replies! I'm not about to agree to an ERCS, and have no intention of consenting to an US no matter what the estimate weight of my babe is! But this will be helpful in putting my DP's mind at ease.... I hope!

[shenanegans]

at a 38 week u/s my son was estimated to be one pound more than he was when he was born, 6lbs at 39 weeks. I definitely don't trust those estimates.

[ann_of_loxley]

I like this website:

http://www.bigbaby.org.uk/

I wouldn't trust an ultrasound for weight guestimations. They can be off by pounds. You have had a big baby and unless you have a very very rare genetic condition where your pelvis is super funky shaped - the size of your baby has NOTHING to do with if you 'can' or 'can't' birth them. Your pelvis flexes in three places and babies have numerous head plates that are designed to overlap and fit through a pelvis. The only other worry with a 'big baby' could be shoulder dystocia but that actually has nothing to do with size, it has to do with postion of baby so there are bodily positions you can put yourself in during labour - or hands on help that can be given to 'correct' such an occurance.

I strongly believe that we would not grow babies bigger than we can birth. This may mean that we end up going into labour a bit sooner simply because our womb has reached maximum capacity! lol But we are like a goldfish bowl and our babies like goldfish... they won't grow bigger than the bowl they are given! lol

My son was 10 and a half pounds as well - he was also breech and I was scared an uniformed at the time so went for the section when I went into labour (they didn't know he was breech until then!)... I thought if I stuck with a really great (GD) diet this time around (though I didn't have GD with my son) that I could hope for a tiddler of a baby! lol...But it looks like I am growing another big one regardless - so I think I too just grow 'big babies'.

[jess152]

No study here, just personal anecdote; pushed out my 9lb, 2oz. VBAC baby on hands and knees. Piece of cake!

My midwife had never seen a rupture in her career (800+ births), and when she told me that, it ceased to be a worry for me. It really is that exceptionally rare.

Good luck!

[eastkygal]

If DP is worried about uterine rupture, I can offer my story. I was an HBAC with my second. She ended up needing a c-section delivery because she was occiput posterior and her cord was wrapped around her arm 3 times, along with her head not being tucked. However, I labored hard with her. She was 11lbs. at birth. I believe she would have been born vaginally had it not been for the malpositioning. Like the PP said, shoulder dystocia is what they worry about often. It can be remedied by positioning, or a skilled practitioner will do the screw maneuver among other things to free the stuck shoulder. Anyway, I wouldn't hesitate to HBAC again. I would try a little to keep baby weight in check, but I wouldn't worry too much. I mean, what can you do? I didn't have GD.

[leavemealone]

Not really a study, but ancedotally, I have had two "big babies" after my first was a c-section for CPD. My first VBAC was 9 lbs 10 oz. My second VBAC (first HBAC), was 10 lbs 13 oz and came out posterior. My c-section for "CPD"? 9 lbs 6 oz.