Which, if any was more accurate for you…growth scan or fundal height?

[Moominmiss]

I’m 35 weeks now and have gestational diabetes which I’m now managing with insulin and metformin.

Because of this I have a c section booked for just over 37 weeks.

Last week, at 34 weeks I had my first growth scan. Baby looked fine and overall they said tracking to be 54th centile, although his abdominal circumference was high at 97th. They said still within normal ranges so weren’t worried and that it’s common with GD babies for their tummies to be bigger.

He was estimated to be 5lb 5oz at that scan at 34 weeks. The consultant I had my appointment with immediately after the scan said babies tend to put on around half a pound a week from that point so I’d be looking at a 7-7.5lb baby.

I actually think because of the GD he’ll put on a lot more than that and be much bigger but time will tell!

I then had an appointment with my usual midwife 3 days later and all was fine until she did my fundal measurement and found I was only measuring 31 weeks instead of 34.

She seemed shocked that my scan had been normal and said had I not just had one she’d be referring me for one based on that.

I know that neither of these methods of measuring are accurate and can be WAY out in terms of indicating either a small or large baby.

But out of interest I just wondered, which, if any proved more accurate for you?
I would assume the growth scan purely because fundal height could be affected by baby’s position etc.

Pretty sure I’ve covered all bases with clothes for baby in hospital anyway. I’ve packed 1 newborn outfit (as I’m fairly confident he’ll be too big for that), a couple of up to 1 month ones (as they go up to 10lb I think), and a couple 0-3 in case he’s enormous lol.

My third baby was 8lb 6oz at 38+2 (no GD), albeit 7 years ago and I’m now with a different partner, but I still think even arriving a few weeks early that this baby will beat that weight by a fair bit!

Hiya, I've had big babies too and always found the scans to be more accurate.

Scan was more accurate for me. Though the fundal growth wasn't too far off. I was always measuring ahead ~2 weeks on fundal growth (never translated to a baby weight though). Growth scan at 36 weeks showed baby was about 6lb 15. Baby was born 9 days later weighing 7lb 5.

Scans

Growth scans have to be done as a set of 3

For me fundal height showed I was on track, growth scans showed baby was growing small.
The growth scan was accurate xx

Fundal height and growth scans both suggested my DS1 was on the smaller side and that was true. He was on the 10th centile for weight when he was born, now he's nearly 2 and is still between the 2nd and 9th centiles.

However I did find fundal height measurements especially inaccurate as they seemed to vary based on where baby was and who did the measurements. When I went in to hospital to have DS I was 39 weeks and the first nurse measured my fundal height at 36cm and said I'd need continuous monitoring and to give birth on the delivery suite because I was measuring small. Then someone else did it again about 20 minutes later and they got 38cm, which meant I was fine to give birth on the midwife lead unit.

My scan was more accurate but both were shite. My fundal height with both babies put me on the 50th centile, scans put me around the 75th.

Babies came out on the 93rd and 99.7th centiles I would never trust them again! Luckily I had 2 very easy deliveries so I think I just grow big babies (no GD as far as we know but I wasn't ever tested as I had no risk factors or symptoms).

Baby #1 was 9lb 2oz and went straight into 0-1 clothes. Baby #2 was 10lb 8oz and went into 0-3. It sounds like you've covered all bases

Neither. Bump measured small, growth scan conversely said huge baby, actually when born at 39+5 he was average size and has remained on 50th percentile ever since. The midwife didn't believe the tape measure and said average based on what her hands and experience told her; the consultant who scanned me also predicted average despite the scan she'd just done. They were both spot on, within a couple of ounces.

Can’t answer yet but due on Thursday and my fundal height has been all over the place, measured 34 at 31 weeks, still 34 at 34, 35 at 38 and 38 at 39 ! Had 3 growth scans and all showed growing at a perfectly normal rate just under 50th centile, I’m thinking I maybe just take a growth spurt and stop for a couple of weeks 😂 also think it depends who is measuring as well

Neither, both were way out

The scan was more accurate but not spot on. I don't think measuring from the outside of the bump really works, I am very short so obviously I stuck out quite far as there's nowhere else for a baby to go! And I was retaining a lot of fluid - went down quickly after the birth.

Had a growth scan at 34w and DD2 measured at 6lb 3oz and around 37w. All of my fundal heights were in line for my dates and DD2 was born at 40+2 weighing 8lb 2oz. DD1’s fundal height measurements were all in line for her dates and she was 8lb 6oz at 40+5. DH and I just make slightly larger than average babies but that’s not surprising. I was nearly 9lb and DH was nearly 10lb!!

My scan was way out. Stated I'd have a smaller than average baby -about 5lb.

Dd came out at 7lb 8 and on 97th venture for height.

Meant to add that DD2’s weight prediction and measuring at 37w was mainly because of her femur measurements. She had long legs.

Scan has a 15% margin for error. Fundal height has a 38% margin for error.

15% is pretty high to begin with!

@Moominmiss, no experience as I'm pregnant with my first baby - 36+3 with GD but just wanted to say that, in my trust, they stop fundal measurements with the midwife as soon as you start growth scans. My midwife said the scans are more accurate (though also not 100% correct from what I've been reading!). I have a c-section in 2.5 weeks and no more growth scans. I have a midwife appointment tomorrow and I'm tempted to ask her to measure out of interest even though I know it's not much of an indicator at all & could potentially cause me to worry! From what others have told me, I will be interested to see how accurate the growth scan measurements are when she's born xx

I had GD but didn't have any fundal measurements as I had regular growth scans so can't comment on the fundal measurements but the last scan at 36weeks said my DS was 5lb7oz and he was born at 38 weeks weighing 6lb12.5oz so the scan wasn't too far off if you account for how much they put on a week roughly. My DS also needed tiny baby clothes so you might not have a huge baby just because of GD

Scan for me. The midwife and consultant were sure on the basis of my fundal height and feeling my abdomen that he was an average size baby - not big. But the scan suggested 9lbs+. Scan was correct - he was born 9lbs 2oz. (Which I realise isn’t a HUGE baby, but fair to say it’s above average.)

My fh measurements put me two weeks ahead. I might tell mw not to bother measuring. I'm on a bmi pathway. My growth scans put me a day or so behind. Baby is following just over 50th centile line, 32 week scan suggested weight was 4lb5 so far.