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!

I always wonder about this as the heavier friends I know have smaller babies & it’s the trim ones who have big ones.
I was just over 7lbs but DH was about 10lbs. He’s big build & 6.2 & I’m a 12 & 5.9.
DC1, tiny bump & small weight gain but ate loads due to nausea & they were worried about placenta flow so I was induced at 40 wks, he was 9lbs 3 & long, so not small. DC1 is only slightly above average height now at 4 & very skinny but both DH & I grew tall late. 2nd pregnancy I was massive, had the extra water thing but baby was again 9lb 3. However he’s still massive now at 20 months in terms of height.

They insisted DS was going to be between 6-7lbs, according to the frequent scans. Considering my lightest up till then had been DD2, born 3 weeks early and 8lbs 6ozs, I thought that very unlikely. As I told them, when I had had her, I could eat breath and move, with my DS I could do none of these easily.

He was born 10 days late, weighing in at 10lb 5ozs, with a very difficult birth, ending in an EMCS and permanent damage to his eye.

I believe it’s genetics and placental function
I had one 5in 14 at 38 weeks other two 7lb 5 and 7lb 4 at 40 weeks
I’m 5’4 and petite build

From distant memory:

Genetics - your parent's birth weight
Your birth weight
Your age
Smoking and drinking
Maternal diet - too little/too much
Obvious things like premature delivery or twins
Other health problems in the pregnancy e.g. anaemia, diabetes
Placental function

Pre pregnancy I'm a size 8-10 and 5ft 4. My first who was a boy was 8lb 13 and ten days early. My daughter was bang on due date and was 9lb 8. I'm 28 weeks with number 3 so who knows! I was 9lb 11 at birth husband was 10lb 11.

Nope my first was 5lb and I was huge, my second was 9lb 1 and I barely gained anything. My third I had repeated growth scans for and was warned to expect a huge baby. Nope one week late and a rather normal 7lb 11oz

I'm fairly petite, just over 5' 3''. DM is around 5' and was also petite when I and my DSis were born. We were 7lb 13 and 7' 5.

I acquired gestational diabetes while expecting DS, which meant I had to stop eating all the nice stuff anything sugary. Possibly why I only put on 1.5 stone and why DS was only 5lb 13.5 oz at birth. I also had pre-existing high blood pressure, so was induced at 39 weeks. He could really have done with cooking a bit longer, but I doubt he'd have been much over 6lbs even at full term. I must have had a crap placenta.

I’m slim, had a tiny bump, was measuring small throughout, was told to expect a small baby, DD was 8lb 14

After having DS1 I was asked to take part in some research into the factors behind ‘bigger babies’. Apparently maternal obesity, gestational diabetes and family genetics (the weights of babies had by grandmother etc) are thought to be the biggest factors.

When I had DS1, who was 9lb, I had a pre-pregnancy BMI of 18ish, wore size 8 clothes and gained very little weight during the pregnancy. I ate pretty much as I had beforehand, with maybe an extra snack each day, had a pretty small bump and my midwife friend was convinced the baby would only be 6-7lb. Interestingly, my mum had also been quite slim, had smallish bumps and not eaten excessively, and her three babies were all over 8lb10.

My bump with the 10lb-er was enormous. Just hanging off me. When I sat down I had no lap, I could even feel the kicks in my thighs when I was sitting. I got a hernia and had to wear a belt. Although my SPD was fine on the 2nd one, which makes no sense 😂 I was 3 stone down in just 2 week.

Weeks after I had him*

DS was early and still came out at 9lbs. However I have a family history of huge babies so knew he would be a big 'un.

Think genetics play more of a role than the mother's size.

my first was 9lb,
2nd 10 lb 8oz ( his placenta was big, took effort to push it out.)
3rd 7lb 3oz
4th 7lb 8 oz

am so glad they didnt get bigger each time.

7lb 7oz is average. My consultant told me that they had a bet with the other consultants on what would be the average birthweight on a particular day at their hospital - and the one who predicted 7lb 7oz (known generally as the average birth weight in western cultures) won.