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Femur length under 5th centile at 21 week scan, sign of Down's syndrome ?

(10 Posts)
Hpbp Wed 21-Mar-12 21:23:19

Hello everyone, my 21 week scan showed femur length inferior to 5 th centile, sonographer mentioned Down's syndrom risk. My NT and tritest came back at 1/1694 a while ago. Should i be worried ? I am not very tall but not short either 1m60 and my OH is 1m78, i am ok if i have a small healthy baby but they are talking about Adown's syndrom, so a bit more serious issue. The other measures are fine. So i don't know what to think ? I do not really want to go for invasive and risky tests for the baby, does that mean i have to live the remaining 19 weeks under worries and concerns ?
Thank you

mrspepperpotty Wed 21-Mar-12 22:31:58

Hi OP, I can't comment on the link between femur length and Down's as I have no knowledge of that, so maybe the first step is to talk to your mw to find out what this means in terms of the risk to your baby.

I was given a risk of 1 in 250 at my triple test and I decided to have an amniocentesis to set my mind at rest. Obviously it's your choice whether or not to go ahead with that kind of procedure, but I just wanted to let you know that I found it very straightforward and much less invasive than I was expecting.

Hpbp Thu 22-Mar-12 20:35:54

Many thanks for sharing your experience. I dont know yet what i am going to do.... Need to discuss implications with my OH. Thanks again

eavers Thu 22-Mar-12 22:06:15

I had a similiar measurement at my 20 wk scan. Femur length was on the 3rd centile (and abdominal circumferance on the 97th centile!)
Obviously it was worrying but I decided not to have a CVS or amnio but it was a difficult decision and did wonder whether i had made the right decision all through the pregnancy.

I decided to have a private 20wk scan at the Fetal Medicine Centre in London. I wanted a second opinion before deciding on what to do. They were very thorough and actually measured the femur at about 20th centile. I had about 6 further scan during the pregnancy (for this and other reasons) and the femurs were then measured from about the 10th centile to the 30th.

DS is now 7 months old and fine, his legs were a bit on the short side when he was born but have grown a lot now. He does still have a really fat tummy.

Hpbp Fri 23-Mar-12 09:34:28

Hi Eavers, thank you so much for this reassuring message.
Very glad your DS is doing fine now and hope you enjoy motherhood.
We have decided to go ahead with amnio and fingers crossed it will rule out skeletal displasia and DS. I had 2 scans, at 21 weeks, one just routine and a second when they refered me to he FMU of UCLH, i will have another scan in a month time, but in between will have amnio and 3 week wait. Hopefully the results will come back at the same time and coherent....

mrspepperpotty Fri 23-Mar-12 21:55:55

Good luck OP

Hpbp Sat 31-Mar-12 14:16:33

Mrspepperpotty, Eavers, I had the first results of the amnio, no chromosome issue so far. Have to wait another 2 weeks to the full karyotype but feel confident. And scan also in 3 weeks. I am a bit less confused and less stressed out. Thanks for our support.

HOMEMADECHUTNEY Sat 31-Mar-12 22:57:47

Very glad to hear of your good news so far. Must be a huge relief to you. The very best of luck for the rest of your pregnancy.

Hpbp Mon 02-Apr-12 17:12:59

Thank you homadechutney. Will try to enjoy now indeed.

lizzieboo Sat 22-Dec-12 12:56:10

Hello, I wanted to post my story to try and prevent anyone else from going through the stress I did during my pregnancy. I used to search these boards daily trying to find reassurance to the point of unhealthy obsession and I really wish I had focussed on enjoying being pregnant and put my worries aside.

A private scan at 18 weeks and my 20 week NHS scan both showed my daughter's femur length to be behind the other measurements by up to a week, plotting between the 25th and 50th percentile lines on my baby's growth chart. After googling 'short femurs' I began to worry.

An ultrasound scan at 32 weeks then revealed I had a mild case of polyhydramnios, or excess amniotic fluid surrounding my baby, and that the femur length had now dropped down to the 9th percentile, between 2 and 3 weeks 'behind' the other measurements which were on or above the 50th percentile. After googling polyhydramnios my worry increased (it can indicate chromosome abnormalities) and despite the poly being attributed to a mild case of gestational diabetes I became absolutely convinced my baby had down syndrome, even though there were no other markers.

Ultrasound scans every two weeks (because of the diabetes) were also less than reassuring - the femur remained on the 9th percentile and at one point when I was 36 weeks the femur measured at 33 weeks while head circumference measured 38 weeks! When i mentioned my concerns to my consultant she dismissed my fears saying they didn't even use an isolated short femur as a soft marker but it did little to reassure me and I became obsessed to the point I was in tears most days, not eating, googling in the middle of the night, analysing my ultrasound scan pictures for 'signs' and ultimately putting strain on my relationship, my unborn baby and myself.

Even though I would love and want my baby no matter what, I was worried sick about our/her future and was battling between acceptance some days and, I'm ashamed to say,  outright fear of meeting her.

I went into labour at 40 weeks and even told the midwife delivering my baby that she might have down syndrome.

My daughter was born after a 9 hour labour and she did not have down syndrome. She was however, only 5lbs 16 so tiny all over!

Because of my worries throughout pregnancy I wasn't 'convinced' she was, for want of a better word, 'normal' and had her checked over by a senior peaditrician who thought I was mad (in hindsight I probably was!). When she asked me why I thought my baby might have down syndrome and I mentioned short femurs, she looked genuinely shocked and said they don't even consider that a marker in isolation, and said my daughter's legs didn't look short anyway!

Apart from the smallness my baby was/is perfect and healthy and is doing very well.

Sorry for the essay but I just could have done with something like this when I was pregnant. Please don't worry away your pregnancy like I did as I really think I made myself mentally and physically ill and put my baby at risk because of the worry (which ironically was probably the cause of her tiny size).

Also, when I was actually in labour I seemed to find a sense of peace with the situation, and I knew then that I would love her and do my best for her no matter what, and the fear of ds seemed to just disappear. She would be my baby regardless! There is also so much support out there and ds really isn't the end of the world.

I hope this helps you. Please, listen to the professionals and not dr google! Relax and enjoy the rest of your pregnancy!

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