IVF baby measuring two sizes 18hrs apart

[magpiecounter]

Hi, we have had the blessing of an IVF baby but it's a scary ride.

I was measured 4.2mm at 7+0 last Thursday at 3.30pm and the sonographer struggled to find the baby so had to do an internal ultrasound. She said the baby was 10 days behind and didn't measure 6 weeks yet.

The next day (7+1) my IVF clinic did a repeat scan at 11am but this time she did a normal ultrasound and found the baby right away. She measured him at 7.7mm and said I was 6+4 which made me almost 4 days behind.

I don't know which one to trust. Both are too small for ivf which scares me but one of them has to be wrong. Anyone experience this and have a good outcome?

As you've discovered, when they're so so tiny (almost microscopic, even a fraction of a millimetre makes a huge difference. Angle makes a ginormous difference when they're that size.

I was two days behind around that stage. 5 days ahead by my twelve week scan!!

It's notoriously hard to measure babies via ultrasound and my doctor was kind enough to warn me in my last pregnancy that I was due to see another doctor the next week as she was on holiday, and that he tended to estimate bigger than she did so not to worry if my baby seemed to jump up a kilo overnight! (this is not uk).

I took from that that not only do the machines vary in accuracy but interpretating what the ultrasound says is also not a precise art.

Measured 3 days behind at 8 weeks and 10 weeks but was measuring ahead at 12 weeks.
I echo what was said.
So early on the embryo is tiny and the angle, visibility, equipment quality, sonographer skills, etc ... can make a big a difference and 1mm is a day at your stage so all this sounds very normal to me.
I wouldn't worry OP x

Sorry you are going through this. Did either scan see a heartbeat? I too was advised that at such an early stage, its very easy to be inaccurate in terms of size. Plus, various machines have different accuracy. I'm suprised the IVF clinic didnt do a TV scan also, as these are more accurate at such an early stage.

I measured a week behind with my 1st IVF pregnancy earlier this year. I asked the question on here, and many women found they'd caught up by the next scan. Unfortunately I MC at 9 weeks, despite seeing HB on the 7 week scan. Seems a mc after seeing a HB isnt so common. Best of luck x

@Elouera both scans saw a heartbeat and the second one the sonographer said it was a strong heartbeat but the baby was snuggled in tight still. The first saw a heartbeat but wasn't forthcoming about it:

Thank you everyone. I'm just so worried because one was wrong but both said ivf babies should measure exact to the day. I hoped having a FET would mean we had a days grace because apparently frozen embryos implant a day later sometimes. Apparently not. They said it should be perfect and the time of transfer and type of transfer make no difference.

Just hope the bigger measurement was the more accurate.

@Elouera so sorry you miscarried. That's my worst nightmare after five rounds of ivf. It's been such a fight to get here that I'm constantly scared of losing him.

Glad you saw a HB on both scans. Thats great. I've TTC 10yrs with 3 mc and no kids, so I know the heartache. Best of luck x

What's odd is the girl who did the smaller measurement wasn't concerned at how far behind I was yet the ivf appointment was more cautious and said she would ask for another scan at about 9weeks

So my last scan sonographer asked for a repeat scan 10-14 days following (21st-25th December) but the EPU said no as the scan showing 4.2mm they did was fine even though it was 10days behind for ivf!! Not sure why one is fine with a 10 day delay and one is concerned with a 4 day delay!

At no point was I told my IVF pregnancy should always measure exactly. I was scanned weekly in the early weeks due to OHSS. I was told how difficult it is to date a very early pregnancy, and a different angle could easily take a slightly different measurement.
I had a scan that dated me 6 weeks, but a further scan 7 days later jumped me to 8 weeks. At my dating scan, I was another 3 days ahead.

@Mackie2020 my ivf clinic were very concerned today when I told them my measurements and have booked an emergency appointment with their dr as it's not right to be so far behind when we know the exact age of the baby. They said a day or two either way can be allowed for but anything over or under that allowance is a concern. They were also quite concerned my GS and YS measurements were not recorded as an indicator of viability.

Just to update. Our baby died.

I’m so sorry to hear this. Exactly the same happened to me a few weeks ago.

Be kind to yourselves and it’s ok to feel angry/sad/numb/nothing xx

I'm so sorry. Please be kind to yourself. I do hope you've got support in real life.

If you want to send me a message separately about anything then please do.
This Christmas is sooooo tough anyway and you just need to take each hour and each cuppa at a time xxxx

So sorry to read your update op.

I'm so sorry to hear this @magpiecounter
I was really hoping everything would be ok for you

So sorry to hear this. Sending thoughts you way OP. Remember that there is the miscarriage association who have a helpline if you need to speak to someone xxx

Oh bless you, this happened to me after ivf a few years ago :-( so sorry op x