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AIBU?

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Original poster

AIBU to think I'm 39 weeks not 35?

64 replies

NameChangedNow · 11/09/2018 17:48

My baby has been measuring massive throughout pregnancy. At 33 weeks she had 37 week measurements. Before this pregnancy I was 3 weeks pregnant then had a bleed. I took one test which was negative. Then got pregnant again immediately. AIBU to wonder if I never actually miscarried and I'm further along than I and doctors think?

OP posts:
HopeGarden · 11/09/2018 20:02

Measurements from scans must be accurate though surely as they are looking directly at the baby.

It’s not quite as simple as that. I’ve had loads of growth scans as my babies have tended to be on the small side.

In the growth scan, the sonographers take measurements of certain body parts from the baby and those are fed into a formula that estimates weight. If those measurements are off even slightly - say because baby’s position is a bit awkward - then that can have a big effect on the estimated weight.

As an example - I had a growth scan for DS1 the morning of the day I went into labour. The growth scan showed no growth since the previous scan. When he was born, less than 24 hours later, he was something like 12ounces heavier than the growth scan suggested. Which was a massive difference from his actual size, given that he wasn’t even 4 and a half pounds when born.

And I know fine well that the doctors had his gestational age correct, as we’d had an early scan before the official dating scan. That’s why they do the dating scan early, at around 12 weeks, because that’s before the size variations between babies large for gestational age and babies small for gestational age start to really kick in.

BabySharkDooDooDooDoo · 11/09/2018 20:04

Gender scan at 26wks ds was 2lb 2oz and sonographer says he would be about 7 or 8lb at full term. I got a scan at 37wks and he was 9lb 1oz. Then at 41+3 when i had him he was 11lb 0.5oz... i got to meet the gender scan sonographer again when my dsis got her scan and she laughed saying how out she was when she gave her estimate Grin

Hidillyho · 11/09/2018 20:04

Scans don’t always pick it up. At 34ish weeks they estimated that my baby was 7lbs. LO was born 5 weeks later at a smaller weight than what was predicted at that scan

MatildaTheCat · 11/09/2018 20:05

Midwife here. 12ish week scans are the most accurate way to date pregnancy as the fetus grows at a pretty uniform rate at this stage. Measurements are taken.

By 20+ week’s the growth begins to vary more. By the late stages of pregnancy there is a wide variation in ‘normal’ weight so it makes complete sense that the measurements will reflect this.

If the fundal height is measured correctly it’s a good guide to steady progress but less good as to exact gestation.

Finally the stature and build of the mother will also make a difference. Smallmwoman with well grown infant = large bump and so on.

One additional final fact is that a well grown 35 week baby will not necessarily be well matured and the same applies in reverse. So allow your baby to grow and develop at his or her own rate and breathe. [smike]

Prestonsflowers · 11/09/2018 20:06

Either way, you’ll find out soon.

Merryoldgoat · 11/09/2018 20:11

The scans can tell you things like if measurement of limbs etc are within normal ranges but it can’t give you an accurate weight.

I had lots of growth scans owing to large babies.

First one was measuring about 9lb so big but not scary. He was 11lb

The second was measuring about 10.5 lb and he was 9.5lb

The scans showed ‘big’ but weight is not especially accurate at all.

spiderlight · 11/09/2018 20:13

I was told all the way through, at every appointment, how mahoosive my baby was going to be. He was 6lb 6. Conversely, a friend was told hers was measuring small and had lots of fuss and even a consultant referral about her tiny measurements, and he was over 9lb.

crispysausagerolls · 11/09/2018 20:13

The scans won’t be wrong about how far along you are because they are looking at organs etc. The size scans can be wrong - I was told DS would be 9lb4 and he was only 9lb

Nicketynac · 11/09/2018 20:18

I don't know anyone with reliable results from later scans predicting size, including people who measured so big that they were induced early or had elective sections and babies turned out to be on the small size. Not sure why they bother with the scans.

Bluntness100 · 11/09/2018 20:19

I missed two periods before I fell pregnant and was being seen by a consultant at the hospital. The result was they were worried about their dating and induced on my due date as they said they could be two weeks out and anything over the 42 weeks started to be dangerous.

They thought my daughter was big, she wasn't she was long. 6lbs four. Top five percentile for height, bottom five for weight.

If they are worried they will induce you, don't worry.

LiquoricePickle · 12/09/2018 01:14

I was told that my baby was going to be over 9lbs. Here was 6lbs6 at a week overdue and was too small for newborn clothes.

Mammaof · 12/09/2018 01:55

On my first pregnancy they sent me for numerous growth scans, warned me to buy tiny baby clothes and not to be shocked when the baby came out as he would be tiny. My last scan was at 40 weeks, I gave birth at 41 weeks and he was 8lb 10!!! So the scans are crap and refuse to have another growth scan on my second pregnancy

Lonecatwithkitten · 12/09/2018 07:47

Scans can be up to 25% put as they don't measure the baby they measure the return of the ultrasonics wave and all kinds of things can alter the return of that wave even a tiny amount.
Dating looks at the development of certain organs which we know with huge amount of accuracy the order and way in which the organs develop,

Stupomax · 12/09/2018 13:05

I went for my 13 week scan and the baby was very very obviously not a 13 week baby - it was very clear that I was 4 weeks further in than I'd thought. Everyone in the room actually gasped then laughed when we saw the baby on the scan. I felt pretty stupid arriving 13 weeks pregnant and leaving 17 weeks pregnant. I'd had a completely ordinary 'period' that I'd been dating everything by but it turned out not to be a period.

littlesos · 12/09/2018 13:27

I was told my baby was measuring small and was tracked throughout the end of my pregnancy. She was 10lb 9oz when she arrived, so measurements are not always accurate.

Elllicam · 12/09/2018 13:30

With my third son I went in with reduced movements and they scanned him at an estimated 7lb. He was born at 9lb 4 4 hours later. Scans can be quite off.

Blobby10 · 12/09/2018 13:31

Admittedly it was 22 years ago and I'm sure technology has improved since then but I was told my first born would be a standard 7-8lbs and he was 10lbs 5.5oz. Was told the same with second who came out 10lbs 6oz and my third was only going to be a little thing compared to her big brothers - she was 10lb 7ozs! Scans can be wrong!

UsuallyOnTime · 12/09/2018 14:02

This reply has been deleted

Message withdrawn at poster's request.

AmIRightOrAMeringue · 12/09/2018 14:06

I don't think the scans are accurate as the baby by this point is too big to fit on one scan picture so they have to scan part at a time and there are infinite number of positions the baby can be in, which make it look bigger or smaller. So I'd take it all with a pinch of salt and go off your and your partners sizes and birth weights

Babdoc · 12/09/2018 14:09

Scans are all very well, but in my view you can’t beat an experienced old Scots obstetrician for estimating weights by simple examination. I remember teasing mine for being half an ounce out - he reckoned 8lbs 6oz, DD arrived at 8lbs 5 and 1/2 oz!

thecatsthecats · 12/09/2018 14:21

They told my sister her baby was average - he came out 100th percentile for height!

Unsuitablelake · 12/09/2018 14:46

Iast two children the scan was waaay off. with my middle child they said that she is going to be big(scan). And she was born 5.9lbs with my last one scan showed in 32 weeks that he is going to be small. as his middle sister. He was born 10.5lbs. Even scan doesnt show precisely

MirandaGoshawk · 12/09/2018 14:54

My twins were born at 29 weeks, by my reckoning. The doctor told my DH that I'd got it wrong, and their development was much further on. But I could do the maths - the doctor didn't know that we hadn't had sex for three months prior to the week we got married, which was the week I got pg!

TheWinterofOurDiscountTentsMk2 · 12/09/2018 15:00

My twins were born at 29 weeks, by my reckoning. The doctor told my DH that I'd got it wrong, and their development was much further on

I can assure you that the drs could tell whether your twins were 29 weeks or much later on (how many weeks did they say they were?) and your calculations were not the accurate ones.

StressedToTheMaxx · 12/09/2018 15:07

I had a similar situation.
I went for a reasurance scan as I had a bleed- expecting to be 6 weeks- and turned out to be 2 days off of 12 weeks. Which was 100% physically impossible for me to be that far on.
They changed my due date and moevd all my scans etc. Then baby started measuring small Hmm
I think it's a bit like guess work sometimes.

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