Higher BMI=bigger baby?

[lucielooo]

I read on another thread recently that mums with higher BMI's are more likely to have bigger babies - sorry if this is a silly question, but why? Is it just a correlation, i.e. larger BMI, perhaps eats more therefore bigger baby. Or is it causal, i.e. even if someone with a high bmi did everything the same as someone with a low BMI their baby would still be bigger?

I feel like this is an idiotic question but hopefully someone can help!

I have a high BMI and my first was 7lbs 12. At this one's 20 weeks scan he was just below the 50th centile, so I don't think there's always a direct correlation. Obesity is a risk factor for gestational diabetes, which can increase baby's size because of persisitently high blood sugar, and baby will have inherited some physical characteristics from it's parents, so I suppose it can happen in some cases.

No idea, but I was told at my appointment yesterday that mine will be 9lb something. Can't remember what my bmi was but I was classed as overweight.
I was a bit slimmer with ds1, who was 8lb 12

what bitingfairy said.

I know small people who've had big babies, and big people who've had small babies. Anecdotal evidence of course, but GD aside, I don't think there's a link, no.

My BMI has been pretty much the same, varying by about 1, but always in the overweight range and mine were 9lb9, 10lb12, 8lb12 and 8lb14.

My BMI was quite low when I had DD1 and she was 9lb5

When I had my 3rd baby my BMI was 31 and DD was just 7lb.

So for me it worked the opposite way.

My BMI was 17 when pregnant with ds (dc 4), so technically a little under the norm I think? He was 9lb 8oz at birth. I've heard of the link with GD, but didn't realise there was a definite correlation with BMI?

I wouldn't think so. I'm classed as having a high BMI but according to 20 week scan, baby was actually a bit small for dates (well within average though). Am now 33+2 and according to my midwife, baby is neither big nor small, but just about right.

I think it depends on the individual, of course.

There is absolutely no scientifically proven correlation between one's BMI and newborn's weight. High BMI places one at a riskier pregnancy category and, if such person's weight gain is not monitored carefully thoughout pregnancy, could lead to numerous complications, including high blood pressure, diabetes, venous trombosis and many others... Higher BMI does not lead to a healthier or bigger infant (btw, bigger does not mean healthier either!)

There's only a link through GD afaik - those women with higher BMI are at higher risk of getting GD and if you have GD, the baby is likely to be bigger.

My pre-pregnancy BMI was just over 30 and so far my baby is measuring about average (54th centile at the last scan we had). I haven't had any issues with weight gain or blood sugars either - have actually dropped a dress size in maternity clothes.

Thanks all - I understand that some of the other complications that higher BMI can lead to, but just couldn't fathom the logic that high BMI would necessarily lead to bigger baby (risk factor for GD aside)

I think it was mentioned in a thread about why you are not 'allowed' a homebirth over a certain BMI

lucielooo I think the homebirth depends on where you are and on common sense.

As I said, I'm classed as having a high BMI and am planning a homebirth. My midwife is fine with it.

I must admit I was highly amused, when at her last visit, after weighing me on the scales I had got in (was fine), asked me if she could use them to weigh herself.

So don't let anyone try to put you off if you want one. Talk to the midwives who attend homebirths in your area and see what they say.

lilly13 I'm interested to note your interpretation as I have always read these issues as bigger BMI=bigger baby=unhealthy baby=already bad mother which does little for my self-confidence.

Don't know how I'd feel if I didn't have DH or my lovely midwife who is v. thorough and reassures me through examinations that baby is doing well and so am I.

With DD1 my pre-preg bmi was 31. She was 6lb 10oz at birth. In current pregnancy, my bmi was a little higher at 32 and so far the scans have shown that he/she will be of 'average' size (whatever that is!) but consultant did say at last appointment (28wks) that she wouldn't be as small as DD1 - though not too big though I hope. I've had no problems with regards excessive weight gain (about a stone so far) or GD in either pregnancy.

My BMI is 31 though on my notes the midwife put it as 29 which is definitely wrong. I've hardly put on any weight so far (currently 17+5) in fact last time I weighed myself I was less than prepregnancy but I know these things change quickly!

I've been told I can have a homebirth if I want one (which I think I do) but then reading that higher BMI increased risk factors got me wondering whether it does matter that the MW recorded my weight incorrectly.

But as I say, I wondered in what way it affected it - and to what extent being as healthy as possible throughout pregnancy and managing weight gain would help dimish any risk.

I think you're classed as higher risk for thrombosis if BMI is over 35 in my area.

But good to hear from everyone that high BMI doesn't necessarily mean big baby - which makes sense!

I have very high bmi but baby is measuring normal size on scans - I think it's another thing they use to scare fatter women and make them feel guilty for.

Like others have said I don't think there is a direct link between BMI and baby's size. I had a BMI over 30 when I had DD & she was late and still only 6lbs 13oz. So not really big at all!

I think it's because the higher BMI puts you at risk of pregancy related conditions like Gestational Diabetes which can lead to a bigger baby. I always measured spot on for dates throughout pregnancy but MW always said baby would be small which I thought was odd!