Short femurs and low estimated birth weight at 35 weeks

[SBC0511]

Hi All,

I was referred for a growth scan at 35+2 by my midwife as baby was measuring smaller than expected on the tape measure.

Had the scan last week and the sonographer who confirmed she had measured 6/7 times picked up small femur bones measuring on the 1st centile which brings babies EFW to between the 3rd and 10th centile. (Head on the 12th, abdominal on the 30th)
They sent me for a follow up Doppler scan a week later (yesterday) which came back normal and I have another growth scan next week when I’ll be 37+2 and they’ve advised if the EFW is still below the 10th percentile I’ll be induced. They measured the other long bones yesterday and all okay aside from humerus which measured below the 5th centile but they didn’t seem overly concerned.
Worth mentioning I was also sent for a growth scan at 27 weeks and all was okay, baby was measuring on the 36th percentile overall albeit, the femurs were still smaller than the rest at this point (9th percentile)

I’ve had 2 previous healthy and ‘normal’ pregnancies with babies born at 7lbs 3 and 7lbs 8 so I don’t usually have small babies. I wasnt screened for edwards or pateaus as they couldn’t get the neck measurements at my 12 week scan but I did have the quad test for downs which came back low risk/negative.

Obviously I’ve spent the last week continually googling all the reasons this can be and I’m absolutely worried sick. Mainly about the short femurs/short humerus but also about the significant growth drop of the EFW overall from the 36th to the 3rd-10th.

Looking for other people’s experiences of something similar and what the outcomes were…

My dd was told the same thing when she had growth scans. We all worried, wondering what would be the cause and if it would cause any developmental problems. We didn't get any answers.
Fast forward to the birth, we were very anxious but needn't have been. He was born healthy, no obvious deformities and, the bone concern was never mentioned.
He had the normal check by the paediatrician and everything was fine.
He's 8 months now and doing everything he should be doing so I'm quite baffled with the short femur concern raised before his birth.

Thanks for your response @Nutterjacks. I have read a few positive stories whereby a short Isolated Femur didn’t cause issues come birth, so that is reassuring, but I think my concern stems from the fact I’ve had 2 ‘average’ size babies, and the growth has slowed over time and only really picked up as an in the 3rd trimester (basically they haven’t always been short which makes me think it may not be just a ‘small baby’)

Glad you son arrived happy and healthy. May I asked what his birth weight was?

We had the same with our second DC. At the scan we were told exactly the same about the femurs. I'd never heard of it being an issue.
Had to go back , I think, a week later for another scan.
Everything was totally normal. They couldn't explain the anomaly. DC was born at a very good weight (& length) and is like a been pole now

I had growth scans every two weeks. They consistently said my DD was going to be small and they were worried about fetal growth restriction. At one point her head circumference was measured at below the 3rd centile and they talked about needing an mri scan. She was larger than average at birth. She’s now 18 months. She does have a smaller than average head but is otherwise absolutely fine.

Thanks @Fleur405 and @ohyesohyesoh that is reassuring. I’m hoping we have a similar outcome but so difficult not to worry!

We were told with my second that he was measuring large around the abdomen and his femur length was short…. Google is not your friend when told stuff like this. He was born very healthy and with a normal tummy and legs too long for his baby grow! Take any extra tests that may help but try not to worry x

DS slowed down in the last few weeks. When he was born it was found I had a partial placental abruption so he hasn't been getting enough nutrients luckily he was only under weight for his length. He's now 9 and currently having a second tea but still skinny, developmentally he has no issues.

Thanks @Lemonademoney. yeah they say not to Google don’t they but that’s the first thing everyone does!

I think my concern is that there has been a gradual decline of femur lengths (and other measurements), as this was relatively normal at 20 weeks and 27 weeks. And it doesn’t seem to be placenta related (as mentioned this all came back as working fine) if it was just a ‘small baby’ surely they’d be small on the other scans

Praying everything is ok!

Thanks @sleepyscientist - did they do the Doppler scan with you? And if so did it look ok? We’ve discussed it potentially being placenta related (which would make sense as to why it’s slowed) but that doesn’t match up with the Doppler scan we had yesterday - they said that all looks good

It’s always scary but try not to worry @SBC0511. One of my DC went from around 50th centile at the 20 week scan to 4th at an extra scan at 33ish weeks which they organised in a hurry when they noticed my bump had been getting smaller rather than bigger. I then got a dodgy ctg trace and they decided to keep me in, and it all looked scary and like we were heading for early delivery of a very tiny baby.

Like you, our placental Doppler was ok and they decided to keep monitoring and checking growth and placenta, and in the end DC was delivered on 6th centile at 37 weeks but healthy and all ok.

Hang in there. The measurements aren’t hugely accurate, and as one consultant helpfully reminded me - someone’s got to be the smallest one in the class photo, it doesn’t usually mean there is something wrong.

I'm in a similar position. Had growth scans from 23 weeks because of low PAPP-A but doppler was normal

Started off around 40th centile at 20 week scan and now around the 12th at 28 weeks. Abdominal circumference still mid range but femur length is low. Seen midwife and consultant after scan and they didn't seem concerned. Having scans every 3 weeks to monitor, but as others have said someone has to be on the lower centiles.

I get how stressful it is though, seeing baby drop centiles at each scan makes it hard not to worry

I had a baby that was dropping down the growth curves. At 37w she had dropped to below 9th and I was booked for induction, although she came spontaneously at 38w. When she was born i had very very high blood pressure and she was a tiny 2.6kg (5lb 12oz). The midwife said my BP could have influenced things (i was on asprin from 12weeks) and her notes say suspected IUGR. She had some issues after birth as she had sepsis but her small size didn't cause that (although it obviously made it trickier for her to recover from). In any case, at 2yrs old she is 79th centile for height,75th for weight and doing great! So even if they are little, it doesnt mean that it is the case forever.

@SBC0511 our Doppler showed a very small area which might have been a haematoma but was sufficient, we are both quite small so it was thought he would just be small. The problems started when I went into labour I was in constant pain between contractions and bleed. CTG was abnormal and he was delivered within the hour. We was born very skinny and slightly jaundiced on day 2 but was managed on the ward and home on day 3. I then got a significant haematoma from the C-section.

We are both in a relevant field so the debrief was detailed as I do have risk factors for this kind of thing. The conclusion was a placental haematoma which had progressed to a partial abruption which likely expanded during labour. It was discussed that he is small in general so it could be the abruption occurred within hours of labour but either way we decided against another one

Thanks for the responses all 🙏

The baby is my grandson, my DD's 5th DC. He was small, just under 7lb
DD is very slight and her other DC's were all small but all healthy.

@SBC0511 I've been for a growth scan today and asked the question about short femurs. The sonographer told me that the data they use for centiles for femurs is outdated due to technology changes, because measurement method's have changed. So despite the way centiles should work, despite scanning so many babies he rarely sees any above the 70th centile so what can seem like a small centile actually isn't

My baby was 15th for femur today and 46th for abdominal but he said compared to other babies that's proportional measurements. So although she's smaller than average, the femur length isn't a concern relative to other measurements

Hi All

As the OP I wanted to a provide a conclusion to this story. If one thing I found frustrating during the turbulent time we went through it was reading threads on experiences only for there never to be an outcome provided.

I won’t go into too depth but ultimately the scan we had at 35 weeks was inaccurate. We followed up the 35 week scan with one at 37 weeks whereby femurs were measuring just fine along with all other aspects of the anatomy.

fast forward a few weeks and we have given birth to a beautiful, healthy baby girl who weighed in at 7lbs exactly.

I don’t want to go into too much detail as the post would be too lengthy but the stress, anxiety, paranoia, fear and every other emotion in-between me and my partner went through in the 2 week period before the 2nd growth scan was nothing short of horrendous. Google is the devil!

At the end of the day, we are incredibly lucky and grateful to birth a beautiful healthy baby girl and I must admit the experience we went through has made us appreciate her just that little bit more but for anyone going through the same in the future, it is very possible scans are inaccurate as evidenced by our situation. The initial sonographer even said they’d looked 7 or so times to make sure they got an accurate measurement…and it was still out.

We’ve been there now, I empathise with any in a similar scenario as it’s so hard not to stress but positive thinking and supporting one another got us through this traumatic experience and we were lucky enough to end up with a healthy DD at the end.

For me, it seems all too often these inaccurate scans happen

Thanks