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Why do midwives

(25 Posts)
Inwaiting Tue 02-Feb-16 17:35:05

still refer to two due dates? one EDD by scan and one EDD by dates. Which one is it? I'm a bit confused why they still report EDD by dates when its been confirmed by scan?

KnitsBakesAndReads Tue 02-Feb-16 19:13:04

My midwife told me that the EDD according to the 12 week scan is the one that midwives or doctors use for deciding if you're overdue etc. Apparently there can be quite a lot of variation in when you ovulate from month to month which you're not necessarily aware of, so they tend to trust the 12 week scan EDD more.

I guess maybe they record the EDD by dates in your notes as that's the date they use to arrange your booking appointment and first scan?

NotSpeaking Tue 02-Feb-16 19:57:47

I thought I knew my date. That was a week ago now, today is my due date via the scan and no baby. Looks like they were right. Annoyingly.

Inwaiting Tue 02-Feb-16 20:11:50

yeah I know what you mean. I just find it odd that they still refer period dates and scan dates rather than just scan dates

SparklyTinselTits Tue 02-Feb-16 20:32:23

It's really odd. I'm still 100% convinced that my dates were wrong.
I told the MW I hadn't had a proper period, just some spotting since my implant was removed before I had dd, but she still used the date of this "period" to work out my EDD hmm DD always measured small on scans, my bump always measured 2-3cm smaller than it should, and DD was 5lb 15oz when she was borN.
DH is in the military and was away a lot around the time that DD was conceived, so from discussing when we DTD, we think DD was born at around 36 weeks rather than 38.
Surely they should just keep the EDD from the scan, and scrap the "dates" EDD!!

littleducks Tue 02-Feb-16 20:41:13

Mine were always altered to scan dates

Lj8893 Tue 02-Feb-16 20:45:11

I'm a student midwife, all the midwifes I work with refer to the edd determined at scan. Before that they work on the last period edd but change it once the scan has confirmed a date.

Never heard of a midwife continuing to use the last period edd if the scan is different!

PerspicaciaTick Tue 02-Feb-16 20:49:17

I knew exactly when DS was conceived as hecus an IVF baby and we know exactly when my egg was collected and inseminated. The hospital still preferred to use their own inaccurate EDDs. DS arrived exactly on the due date calculated by the IVF clinic, approx. 1week after the hospital EDD.
All dates are approximate and babies have a 4 week window within which they can reasonably be expected to arrive.

Lj8893 Tue 02-Feb-16 20:53:49

It's an Estimated due date for a reason, it can never be 100% confirmed by scan.

I don't think women should be given a date, they should be given a date from and date to.

Inwaiting Tue 02-Feb-16 21:39:05

I just don't see the point in recording the edd by dates if they just go by scan? I just wonder if there was a reason why both is still recorded that's all

zzzzz Tue 02-Feb-16 21:43:46

grin they used scan date with mine despite the fact they were IVF so we were pretty sure of our dates wink

GingerCuddleMonsterThe2nd Tue 02-Feb-16 21:47:21

Sparkly I'm the same as you, DP in the military and the date they had drummed up made no sense for conception! DP wasn't around for the 3weeks this miraculous conception would have occurred in hmm

The scan didn't help much either as DS measured small through my pregnancy so they kept telling me I was 14weeks along and I was more like 18! DS was born at 37weeks to EDD but on "investigation" they actually decided he was term amd probably more like 41 and just small. Words fail me I'd been telling them this for nearly 9 months hahaha I know when I have sex....it's not often these days with various postings haha

Blueprintorange Tue 02-Feb-16 21:52:33

I had an issue with my dates - the midwife was adamant my due date was later than the one I'd been given by the IVF clinic, and then said the baby was measuring big confused

Not massively important, but I wanted it to be correct incase I went overdue and needed an induction earlier than they thought was needed IYSWIM. Thankfully I had a very sensible consultant who changed the date to the correct one for me.

Lj8893 Tue 02-Feb-16 21:57:26

They use last period dates to work out an EDD in order to get your scan booked for the approximate right gestation and for booking bloods etc. once you have your scan the EDD is used from that, more often than not it won't change or will only change by a couple of days. (And even still it's not 100%).

eurochick Tue 02-Feb-16 22:37:55

Mine was also an IVF pregnancy. I just corrected the EDD on my notes. They don't need to guess when conception occurred if it took place in a lab! Most people I dealt with got this. My GP seemed to be confused...

unimaginativename13 Tue 02-Feb-16 23:21:36

They use the scan as then they place all babies at the same size, then the EDD is 28 weeks after.

To the comment that said the baby didn't arrive 9months after their expected date, this is why is all estimated. It's from 38-42 weeks so just a ball park number so to say.

unimaginativename13 Tue 02-Feb-16 23:24:10

Just to add both are recorded as you usually have your booking in appt before the scan, so 'your date' and your scan date are recorded.

Inwaiting Wed 03-Feb-16 06:50:28

I understand that they generate my booking appointment and scan date from my last period date. I'm just confused why they still refer to it 20 weeks later in scans when they will only go off scan dates anyway. It's not really an issue I just wondered why they still refer to both if they will only take scan dates anyway.

Lj8893 Wed 03-Feb-16 08:19:14

Like I said, I've never know a midwife to still refer to the last period edd after the 12 weeks scan.

wonkylegs Wed 03-Feb-16 08:31:30

Mine only uses my 12wk scan date and to be fair she still always asks me. My consultant uses the scan date. And we've all accepted that for various reasons it'll be a nice and surprising if I make it that far but highly unlikely.

FatimaLovesBread Wed 03-Feb-16 08:46:44

I've never known a midwife refer to both dates. Only the scan date once updated.

In our case it's an ivf pregnancy so they've just gone off that date event hough all my scans have measured ahead. They'd want to induce me at 40 weeks so which would be 39 if they went by scan dates

Wardrobespierre Wed 03-Feb-16 09:35:15

I've had babies in two different areas and never had a mw refer to the date by lmp once they have a scan date. And I saw many different MWs. Maybe you should ask op? Maybe it was a mistake? How do they refer to it?

skankingpiglet Wed 03-Feb-16 09:39:48

My midwife has never referred to both, once I had had my scans they went by that. It is very annoying when they have clearly adjusted wrongly though, and I'm sure I once read there can be as much as a 15% difference in different sonographers measurements which would explain it being wrong. This time I only had my lmp to go by so feel ok to go with the scan but last time they adjusted my date meaning I apparently ovulated before the single incident of contraception failure which resulted in DD hmm Perhaps not a massive thing in the scheme of life, but DD was born by elcs due to breech and the correct date would have meant a few more days cooking as they wanted her out a couple of days before my edd. The closer to fully cooked the better IMO.

SparklyTinselTits Wed 03-Feb-16 09:52:58

piglet that's what bothers me too.
I had majority of my antenatal care in Germany, but gave birth in the UK.
I'm going to ask one of my pregnant friends who is still in Germany what date her MW is using...it might be the norm over there to use the "dates" date rather than a scan date...but still can't see why it would be hmm

TriJo Wed 03-Feb-16 14:22:48

My EDD by dates (20th February) and by scan (20th March) are 29 days apart - the "by dates" one was pretty much filed under "let us never speak of that again" at my dating scan. I had a private early scan before booking as I was really unsure on dates.

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