12 week scan changed due date to an impossible date - worried about impact on C-section timing

[duedateworry]

I tracked my cycle with LH strips, which pinpointed the LH peak / day of ovulation. Once pregnant, I had my HCG tested at 11, 13 and 15dpo. The results were exactly in line with what they should have been on those days.

At my 12 week scan, the due date was changed to be four days earlier.

This would mean I ovulated on CD8(!), and days before getting an LH peak. It also means that the HCG results (which they’re now saying were taken on days 15, 17 and 19 dpo), would have been completely out of sync with what they should have been.

I know the date they’ve given me is wrong and I’m worried that the c-section I need to have will be set for a date four days too soon.

Has anyone had any joy in getting the NHS to change a due date that is patently wrong?

Due dates move all the time. 4 days is nothing to stress about. I had a scan at 7+2 due to previous losses which put me at 6+2. I've stayed on that trajectory since and remained a week behind at my 12wk scan. I presume I ovulated slightly later in my window and baby implanted late.

My Sister had to give birth at 34wks due to pre-eclampsia. She went in for BP check on the Thursday (after previous concerns etc) they weren't happy, kept her in, injected steroids and delivered my niece by C-section the next day. My niece didn't even go to NICU! She was tiny but strong. I'm sure 4 days at 38/39 weeks really won't make a difference! Furthermore, you'll be getting monitoring - including growth monitoring if there are any concerns. As a PP said, try not to engage too much with these worries. There are plenty of other factors between now and baby being born that might impact due date etc!

You really need to relax about it! Scans at 12 weeks have a margin of 'error' for dating as the foetus is so small - even 1-2mm can make a difference of estimated due date. And remember it's an ESTIMATED due date.

You'll be scanned again, and babies are considered full term from 38 weeks so a few days is not going to make any appreciable difference.

Both of my elective C-sections were at 39+4, you do have some choice in the matter. And if there is a weekend/bank hol etc in the way it will automatically shift later. 4 days is nothing though, please don't worry.

I knew with absolute certainty what my dates were. They dated me 4 days ahead and wouldn't change it. It didn't matter in the end. When it came time to book a csection, I had no issues with the consultant getting it pushed out a few days but baby came naturally a week beforehand anyway. I would try and put it from you mind.

It's all about when you implanted.

Exactly the same thing happened to me.

Knew the date I ovulated because I was tracking. I got a very early positive pregnancy test at 8dpo so know I implanted early. Dates pushed forward by 4 days at dating scan.

Went into labour at 38+3 anyway and had my ELCS brought forward. All was absolutely fine.

Really really do not worry about being 38+3 if they bring you forward.

If they have any concerns about baby they’ll induce/c section from 37 anyway, so 38+3 would be great. 4 days at 39 weeks is nothing, 4 days at 37 weeks yep could make a difference. I was born at 34+2.

I was told my baby needs to be out by 39 due to growth issues, well I’m 39 today and freaking out that they’re leaving baby in too long because they don’t have any beds. I wish they had of got me in at 38.

Also it’s not ovulation date, it’s implantation date which I don’t think you can track.

Honestly you need to chill. You’re 12 weeks and don’t need to stress about c section dates yet. Four days is not going to make much difference either way.

Could you ask that your c section be 4 days later? I guess they are trying to guard against the mum going into spontaneous labour so might not want to leave it until 39 + 4, but you could ask. Even two days grace might make you feel better

Another who had IVF so I knew to the second and my dates still changed

Babies grow at different rates, and not by the textbook, a few days here or there makes no real difference.

I heard a fascinating piece on Radio 4 this weekend about this. Worth a listen. Essentially because a baby is full term from 37 weeks it makes very little difference. The estimate is there as a proxy.

They will scan you a couple of weeks before and will shift the date if the baby looks behind in terms of growth. If it's any consolation I have always had big babies and my due date has been adjusted by up to 10 days every time at the 12 week scan (to an impossible date). 4 sections at '39 weeks' and none have had any issues at all. Home with all of them within 24 hours.

Frankly I think you are over stressing. They will monitor you and change dates if needed.
My own kids were born early (both scheduled for section on medical grounds) but my son wanted out at just under 37 weeks. At over 10lbs then I was delighted. They scheduled sections at 38 weeks at that hospital.
My doctor father said he stopped worrying after 32 weeks.

I had this too with my first, knew the 12 week scan had dated him early. In spite of other posters here patronising you about being over anxious etc, there are reasons why they want c sections in "normal circumstances" to be after the 39 week mark particularly relating to the baby's lungs if I remember correctly (just look at research papers online and you'll find it is strongly evidenced). I pushed hard with obs for as late as poss for this reason and got 39+4 (which nearly got bumped, was last of the day!). All went very well, 10/10 apgar scores and no issues whatsoever. I'm glad I made thisnextra effort. Especially as I really feckin' hate being pregnant!!!

I felt implantation in the early hours of 8dpo, so knew I’d get a positive pregnancy test 48 hours later once HCG had risen - sure enough 9dpo was negative and 10dpo was a positive.

Thank you - the 39 weeks info is promoted by organisations such as Tommy’s!

I had my elcs at 39+6. I needed to be delivered before 40 weeks for medical reasons and they were happy to let me pick any weekday that fell in the 39th week. So if you get the choice just go for 39+4 onwards.

Full term is classed as 37-42 weeks. My boy was a 34 weeker due to preeclampsia. No breathing issues at all.

Term is 37+ but for c-sections it's known that babies born before 39 weeks do have a slightly higher chance of respiratory distress syndrome. It's not common but there is a difference between vaginal and caesarean births 37-38/40.

Ah @littlemissalwaystired I didn't know that. My son was also a c section but he was fine at 34 weeks. Depends on each child too I guess

They are quite hot on the 39 week thing where I live. I was literally living on the prenatal ward from 37 weeks because DD was transverse, but they refused to do the section at 38.6 as it was new years eve. So I had to wait an extra 5 days just sitting there! I was livid at the time.

Sorry the day I was 39 weeks was new years eve and they wouldn't do it one day early as then it was pre 39 weeks.

OP, you are only at the beginning of your pregnancy journey and you don’t want to make your whole experience a negative one because of stressing over every single thing you read online. As people have already said, if there is any need for baby to come out via c section earlier than 39 weeks the doctors won’t hesitate to do it. I know two women who had an EMCS at 37 weeks due to preeclamsia and the little ones were healthy with no breathing issues. Best advice you can give yourself is to stop reading what’s on the internet and interpreting it word by word and instead leave your pregnancy in the hands of the professionals who know what they are doing.
If you are still worried about it in a few months time when you see a consultant to discuss the c section, then you can mention it to them and see what they think. Most c section dates won’t get confirmed until 32-36 weeks so you can either spend the next months worrying or try and enjoy your pregnancy journey xx

I think one thing to remember is that loads of (maybe even most!) people's due date is out by a few days. I knew mine was a few days out, but the calculation error meant I was "allowed" to go right up to 42 weeks without an induction.

So I would try not to worry about it: if your due date is "wrong" as you approach it you can just tell your Drs and let them decide whether to worry about it. (They won't.)

Also as PP have said it may very well get changed.

Another IVF pregnancy here, 5 day blastocyst implanted so I knew dates exactly. However at 6 weeks scan we were 5 days ahead and continued on that trajectory..so my due date is actually a week before the date it 'should' be. I am 26 weeks now and have had a few extra scans but never any mention of an issue with baby being small for dates so guess she just implanted and grew quick. As others have said babies can come anytime between 37 and 42 weeks so I wouldn't worry too much.

You are right that the research show baby is best to be born after 39 weeks via caesarean section. When booking your elective, just ask for 39+4 onwards rather than bang on 39. It is never guaranteed to be booked for the exact date you are 39 weeks as it may fall on a weekend, be fully booked or some trusts only do electives on certain days of the week.