What determines how heavy your baby is at birth?

[turquoise88]

I mean, aside from babies who are born very early and obviously small(er).

There probably isn't a definitive answer but it got me thinking. The last three women I've known to give birth are all what I would deem to be slim build (size 8/10) and have had big babies (9lb +).

I know some curvier women with higher BMIs and almost all have given birth to babies between 5lb and 7.5lb.

Is it weird to assume there would be a correlation between the weight of a mother and the weight of a baby?

I don't really know what the point of this thread is, other than I'm interested!

How well the placenta functions comes into it which can be in itself affected by genetics. Several of the women in my family have a common blood clotting disorder which means we have a tendency to having babies that weigh less.

I was told that it's something to do with how the placenta functions. Apparently mine was massive (twice as big) and that's why I had huge babies, my biggest was 11lb 13 at 37 weeks

I think it is mostly genetics. I am a a slim 5' 5". DH is 6' 2" and also slim.

Our babies were dd1 almost 9lb dd2 almost 10lb and ds almost 11lbs. He was very long (tall) and the weight was his long limbs, hands and feet. At 12 he is 5' 8" and his birthday is not till next summer. He is still slim and tall. His sisters are 5' 4" & 5' 9". But many members of both our families, men and women are a lot taller.

I think genetics - mine were 9lb 3oz and 10lbs 15oz at 38.5 weeks so big babies! I was tested for GD (3 times with DS2) and negative, had healthy relatively easy pregnancies.

I was 8lbs 12oz and the smallest of 3 siblings, DH was 10lbs 8oz, of our 4 nieces and nephews there’s only been one who was below 9lb.

We’re all various shapes and sizes and heights but all within a pretty normal average range.

Wow imaflutteringkite! Did you have a vaginal birth?! I was so proud when I pushed that monster out of my fanjo! 😄

It is genetics and placenta.
Bigger babies can be longer so not necessarily more difficult to deliver, weight in arms and legs doesn’t interfere.
It’s all about the shoulders :(

I had a consultant tell me "the best guide to the size of babies you'll have is the size of babies your mother had".

I was asked my own birth weight in am early appointment with DC1 as part of a study into this.

I was 6lb 10. DS was also 6lb 10. DD was 6lb 5. So fitted in my case.

I think it's a combination of factors.. I was only 6lbs 12oz and put on less than 2 stones during my pregnancy with DD (from 8st 8 to 10st 6), yet she was 8lbs 8oz! Think my DH's genetics were a factor here as he was nearly 10lbs when born.

I think good maternal nutrition does play a part too.. That's why birth weights have increased over the years.. we eat a lot better now than we used to. That is why on average heavier babies have higher IQs.. because they're better nourished in the womb.

That's interesting about placenta size! And wow, imaflutteringkite!

Don’t know really. I’m slim and was the same starting weight with both mine. First was 7lbs ish, second was 8lbs 8oz. 3rd shaping up to be bigger. No change in eating habits/exercise levels etc. I was 6lbs 1oz so seemingly no correlation with my own birth weight. Who knows!

Oh and I put on about a stone and a half with both babies, and at 31 weeks with this one have put on a stone so far.

I think it must be hard to predict for a first baby as it's that explosion of genes coming together that hasn't happened before. I was an average size baby (7lbs) and my DH was around the same. I had a 9lb 5oz baby at 38 weeks! My midwife told me that some people have super rich placentas. I ate like an absolute beast all through pregnancy but didn't gain a huge amount (under 2 stone) and I'm 5'10 so it sort of made sense but I also thought it was just one of those bullshit things midwives say

I'd say it's definitely placenta size/function. I was unable to eat much at all from 20 weeks onwards due to having the most horrendous heartburn. My DD was 9lb3 and DS was 11lb1. In DS's case, the placenta was almost as big as him, which explains why I literally resembled a beach ball with legs

I put on 1 1/2 stone with my first & she was 7lb 1oz (born at 40 weeks exactly). With my second I had morning sickness throughout & only put on 9lb (I was also half a stone lighter than with my first when I got pregnant with my second), she was 8lb 4oz at 40+5 - all through pregnancy the midwives had told me she was going to be enormous!

I’m 5 ft 3 and had a BMI of about 29 pre-pregnancy I think.

I’d love to know! I’m small, 5’3 and size 6-8 (although I was a little bigger pre kids) and I weighed 4lbs 8ozs when I was born (full term). DH was 7 pounds something at birth.

Both of mine were over 8lbs - DD1 was 8lbs 7.5 and she was 57cms long! I developed a major sweet tooth whilst pregnant so I imagine that might have contributed to her size?

DGS was 6lb 3oz, DD is 5'10" and 12.5st at delivery, DSIL is 6'3" and 19st. They're both mostly muscle. DSIL weighed 9lb 11oz at birth, his brother was 10lb. DD was 7lb 8oz.

It doesn't necessarily follow that if your mother had huge babies you will too. I was 9lbs, my sister was over 10lbs. I listened to all of this and my mother saying that "newborn" clothes would be a waste of time so just bought 0-3. First baby was 7lbs 7oz which is almost spot on average. Second was almost 9lbs, but she was 10 days late. Third was between the two.

Oh and congrats to Scottish conservative leader Ruth Davidson who gave birth to a 10lbs 1.5oz whopper yesterday! Well done that woman.

I seem to be following my mother's pattern. I was 6lb something my brother was 10lb something. My 1st was a 6lb11 girl, my 2nd is predicting much bigger, I'm measuring bigger...

I'm 5'4," DH 5'8" both slim build. I didn't put on much excess weight when pregnant and DS was 8.5. He's now over 6', no idea why!

I'd love to know too.

I'm 5'4 and usually weigh around 8 stone, DH is 6'4 and slim . I was 9at4 when I gave birth to DS1, he weighed 8lb 3 but had a huge head.

When I had DS2 I was only 8st11, I put on 11lb in that pregnacy as I was bed bound with severe SPD. He was born at 37 weeks and was 8lb and 60cm long with a massive head.

My mum used to say my sister was a big baby because she was 6lb 12 when she was born at 37 weeks. I was 7lb and my brother 7lb 2.

My sister is much taller than me and has a much bigger frame but all her babies were at least a pound lighter than mine.

I struggled to eat when of with my first child. What I did eat was in tiny quantities and of limited selection. I lost a lot of weight. Baby was 6 lb 6 oz

With my second child I was constant hungry, vomiting 4 times a day but eating 6 meals a day. I gained weight as I should have done over the pregnancy and baby was 8 lb 13oz.

I always assumed it was to do with my nutrition.

Mine were all between 6lb8 and 6lb13

I assumed because both myself and their father are average height but slightly built (narrow bone structure) that my babies were all small. My babies were all slightly smaller than I was when born, but slightly bigger than their father was.

My dd1 was 11 days late 9lb 1oz and dd2 was 5 days late and 8lb 6oz although i was told she would be over 10lb from scans.
Me and my dsis were both 11 days late and 6lb something.
Dsis dd1 and dd2 were both 11 days late and 7lb and 5lb. Her ds was 3 weeks early and 5lb.
I don't know about weights being genetic but in our family gestation is definitely genetic.

material stress can impact on birth weight (babies can be lower birth weight)