No idea on due date?

I'm somewhat confused with this one. I have never had regular periods, so can't remember when my last one was, let alone my cycle length.

We had our first scan on Saturday (13 October) and the sonographer said I was exactly 5 weeks and 4 days judging from the size on the scan. However, when husband and I worked backwards he was away that week!!!! So therefore, we worked out that Junior was conceived on 30 August which would make us six weeks.

So, when am I due? An online thing thinks 23 May 2009, but a doctor has said early June 2009 and my maths puts us due on 30 May 2009.

Any thoughts?

Cheers,
Fiona

The US dating scan is pretty accurate but not spot on. When you are measuring something so tiny it is easy to be half a mm to the left or right, changing the EDD.
If bub was concieved on the 30th of August your EDD would be 23rd of May. That is 40 weeks from the first day of your last period, which theoretically was on the 16th of August, 2 weeks prior to conception.
Am i making any sense??? lol

Early scans are usually quite accurate.

Maybe I'm misunderstanding your post but if bubs was showing as 5w 4d on Saturday then that means you would take two weeks off that (as they include the two weeks prior to O when calculating due date) to get an estimation of when you conceived which would mean your O date was actually around Sept 16th.

Taking two weeks off again would give you a rough LMP date of 2nd September (although yours could've been different, that's how they work it out).

That would give you a due date of 9th June. That means today you are 5weeks 6 days pregnant which matches exactly what the scan said on Sat.

Remember that sperm can last for several days so you may have DTD several days before 16tth Sept which then resulted in this pregnancy.

You are making sense. I have no idea when my last period was, and they are such a non-event I'm unlikely to remember either!

I've now got an appointment with an OB next Monday, so will hopefully get some more direction then.

I'm going to change my ticker in the meantime. I do hope I am due on 23 May. Means less time until I can tell people! Woo!

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Early scans are usually quite accurate.

Maybe I'm misunderstanding your post but if bubs was showing as 5w 4d on Saturday then that means you would take two weeks off that (as they include the two weeks prior to O when calculating due date) to get an estimation of when you conceived which would mean your O date was actually around Sept 16th.

Taking two weeks off again would give you a rough LMP date of 2nd September (although yours could've been different, that's how they work it out).

That would give you a due date of 9th June. That means today you are 5weeks 6 days pregnant which matches exactly what the scan said on Sat.

Remember that sperm can last for several days so you may have DTD several days before 16tth Sept which then resulted in this pregnancy.

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Hi Satya,

Thanks for that. Also makes sense!

What does LMP mean?

Cheers,
Fiona

LMP is last monthly period.
Hope your OB can shed a little light for you. All the best!

ETA: I know you said they are a non-event (lucky girl! LOL!) but can you look through your diary at things that you were doing (e.g. going out somewhere like to a friends' place) and think, was I riding the crimson wave then?
It's a tricky one because if your period was irregular anyway that can make the due date different...

Sorry, LMP means last menstrual period.

A due date of 23rd May is not consistent with a scan that showed 5w4d on Saturday. I'm presuming you meant you had the scan on Sat 11th October (you typed 13th and that's today's date. If Sat 11th Oct is correct and you were 5w4d on that day then the due date based on a 28 day cycle (most GPs & OB's will calculate it that way regardless of the length of your cycle) is 9th June 2009.

You don't count the 5w4d from conception, it's from the LMP which in your case would be estimated to be around 2 weeks before ovulation date. So bubs is actually around 3w4 days in reality but would be referred to as 5w4d. So when you reach 40 weeks bubs is really only 38 weeks (when you take off two weeks that it takes on average to release an egg after your period arrives).

I hope that hasn't confused you, but I probably have.

Anyway based on the scan I still say you would be due 9th June. Not that it matters, bubs usually don't arrive on their EDD anyway as of course it's only an estimate. With different doctors opinions and scans I was due somewhere between 28th June to 3rd July but bubs arrived 23rd June.

Ok, that's all good. We were calculating 38 weeks, rather than 40 weeks.

9 June eh... That's miles away!

Thanks for your help.

Ahhh the old add two weeks got ya! I bet DH was worried being away at the time you thought was conception! :lol:
Yeah, what satya says makes sense, my calcs were based on the day you thought you concieved in your original post. (30th Aug) ;)

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! I bet DH was worried being away at the time you thought was conception! :lol:(30th Aug) ;)

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We did laugh about that. In the ultrasound he was straight on the blackberry to check the dates!