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How do you calculate how many weeks you are?

(19 Posts)
Guyropes Wed 17-Dec-14 18:16:06

Hello everyone, sorry for being a bit thick, but can anyone explain to me why there are people on here with a similar edd to me, but who are saying they are different amounts of weeks along?

It's very confusing. I thought you count from your lmp, or 14 days before your ov date if you did not ov on day 14. Is that right? Also I thought pregnancy lasts 40 weeks so your edd is 40+7. What am I getting wrong?thanks in advance

eastcoastmum2014 Wed 17-Dec-14 18:36:15

You calculate it from the first day of your last period, so the first two weeks you are not technically pregnant! So for example the first day of my last period is 17th April 2014 which makes me 35 weeks tomorrow. Hope that helps!!

MrsGSR Wed 17-Dec-14 18:41:30

Your edd is 40 weeks after your lmp smile

Guyropes Wed 17-Dec-14 21:31:44

Thanks east coast and mrsg....

Is your edd 40 +0 or 40+7?

divingoffthebalcony Wed 17-Dec-14 22:29:23

40+0 from your LMP.

birchwoods Thu 18-Dec-14 08:17:57

Guy there are loads of websites that will do it automatically for you either by your lpm or ovulation date if you know that. MN and babycentre calculate it for you and NHS. Google due date calculator.

GotToBeInItToWinIt Thu 18-Dec-14 08:24:32

Don't mean this to sound rude but why do you think it's 40+7? Pregnancy lasts 40 weeks so it's 40+0. Just wondering if there's something I'm missing smile. As a PP says if you google 'due date calculator' a website will do it for you. My lmp was 1st October and my due date will be around the 8th July.

Rumplestrumpet Thu 18-Dec-14 08:26:04

I had this same confusion Guy , I calculated 40 weeks from lmp, or 38 weeks from fertilisation (IVF so we know the moment of fertilisation!). But then my midwife counted exactly 9 months from fertilisation, which puts my due date back by a week! I was very put out, and tried arguing with her. But then I realised that it doesn't really matter at this stage - baby will come when s/he is good and ready, probably not on either days we've picked!

Guyropes Thu 18-Dec-14 13:57:52

Hi thanks for your responses...

Got to be in it... I was thinking it might be40 whole weeks. So the whole of week forty might count? My maths is not so hot! I'm never sure wether to include the start/ end point when I'm calculating duration!

Rumples... Thanks! I was beginning to feel I was the only one who didn't get it.

I have used the edd calculator based on my lmp and am happy that its correct, i just didnt know how many weeks that meant i was! I think I've worked it out now though.

GotToBeInItToWinIt Thu 18-Dec-14 14:18:21

Ah ok, makes sense smile. Have you seen a midwife yet? They will tell you how many weeks you are.

MaltedMilkBiscuits Thu 18-Dec-14 14:40:38

The end of week 40 is 41 weeks! I am 31 weeks but I'm in my 32nd week, does that make sense?

Anyway, they give you a due date at your scan and always work from that so it doesn't matter either way!

birchwoods Thu 18-Dec-14 14:50:22

Guy now that you know your EDD download one (or a few) of the pregnancy apps on your phone. They will ask for your EDD when you register and they will tell you how many weeks and days pregnant you are every day and show you what the baby looks like and how big it is. smile

Number3cometome Thu 18-Dec-14 15:30:45

Your EDD is 40 weeks after your due date, unless you are me and don't ovulate on day 14 and infact ovulate on day 21!

My EDD is 41 weeks after my LMP grin

Dating scan worked that out for me.

Guyropes Thu 18-Dec-14 15:34:45

Hi birchwood aha, so that's how you're all working it out!

I need to find an app that's discreet as my children go on my phone, and they are not in the know yet!!!

minipie Thu 18-Dec-14 15:36:27

There are loads of websites which will give you your due date, but there's also one website I found which gives you a whole calendar of what week of pregnancy you will be in at what date. V useful for working out when you'll have your scans, appointments etc.

link here

MuddyWellyNelly Thu 18-Dec-14 17:04:31

Minipe that's a good link, but in case anyone has the same issue I did - I tried to put IVF transfer day as 5, but it kept resetting it to 1. So I've had to fudge it a bit. Really good once I'd figured it out though.

minipie Thu 18-Dec-14 17:27:03

muddy are you pregnant?! I remember you from 10+er thread... so pleased for you if so!

MuddyWellyNelly Thu 18-Dec-14 17:55:48

Minipie, yes I am grin. Thank you. We ended up doing donor egg in the end, but I'm very happy with our choice. Am 8+2 today, had a scan a week ago and all looked well but obviously still terrified at such an early stage.

minipie Thu 18-Dec-14 18:15:29

smile flowers many congratulations and fingers crossed, if you have seen a heartbeat that is fab news grin

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