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anyone understand conceptions, scans, due dates??

(18 Posts)
sparklingreactions Tue 06-Jan-09 14:58:18

Hi all just wated to know if anyone really understood how scans date pregnancy and how accurate they are?

i had a scan at 8 weeks and another thats tied in to within 5 days and another later on which tied in to within a day of the first one (although they took my date from my second scan)

just wondered how i would work out conception and a few other things just so i understand abit more??

why they add 2 weeks?? do they only add 2 weeks even if you have a longer cycle? is it just an estimate of when your period was from when they think you concieved?

can you count back 38 weeks from your due date to get a conception date?

why didnt my period tie in with my scan dates?

anyone that can help id be realy grateful xxx

sparklingreactions Tue 06-Jan-09 15:04:19

Anyone? x

ten10 Tue 06-Jan-09 15:13:03

2 weeks are added because they date the start of the pregnancy at the first day of your last period, and then most women ovulate on the 14th day of their monthly cycle,

so you are counted as being pregnant before you actually conceived,

sparklingreactions Tue 06-Jan-09 15:20:48

if i count back 38 weeks from my due date it gives the date of which i think i concieved. however if i count back 40 weeks to the lmp it doesnt match up to where i had my period its a week and 3 days out is this normal?

MrsHappy Tue 06-Jan-09 15:32:30

Perfectly normal in anyone who does not have a 28 day cycle or ovulate on day 14 (which is the vast majority of women).

sparklingreactions Tue 06-Jan-09 15:42:29

i had sex on the 16th of june and my 8 week scan(i counted back 6 weeks to conception) showed the 18th is this okay? with the added 2 weeks it showed my lmp to be later than it was but as u said its normal would u trust the scans?

Lulumama Tue 06-Jan-09 15:42:43

hi, you seem to have posted a lot about your confusion re your dates, you really should speak to your MW and get some reassurance from her

also, you posted that you thought your waters were leaking, did you get checked out?

hope all is well

sparklingreactions Tue 06-Jan-09 15:44:07

yeahh got that cheked mw doesnt seem to be too concerned as she had a look up and couldnt find any signs of leaking just told me 2 wear a pad if it happens again and get it checked soo releived!

Lulumama Tue 06-Jan-09 15:44:48

your due date is estimated

a normal full term pregnancy can be anywhere within 37 - 42 weeks

only 5 % of babies are born on their due date and the date is estimated based on a cycle of 28 days and ovulation aroudn day 14, whch obviously not every woman has

the earlier the scan, the more accurate

a difference of a few days really does not matter

why are you so concerned?

the two weeks added are the two weeks before conception is deemed to have taken place and is added for everyone

that is why your due date is estimated not an exact date of when you will deliver

Lulumama Tue 06-Jan-09 15:45:39

well, taht;s something

but am really wondering why you are so worried about the scan date, it really does not matter that your dates are 5 days out

sparklingreactions Tue 06-Jan-09 15:47:26

iv spoke 2 my midwofe and i never seem 2 understand her she makes it sound sooo complicated about all this 37-42 weeks an plus 2 weeks an shes told me that my dates seem fine but im not convinced i just feel so huge and am convinced im a month ahead of what they think i am my period came at the end of mat and lasted into the veri beginnin of juse i got pregnant on the 18th acording to my scans but i just feel so massive maybe because im onli tiny hehe xx

sparklingreactions Tue 06-Jan-09 15:49:41

no im not aorried that there 5 days out im just concerned as to why i feel so huge and that my period was over a week out 2 where the scan said it was i just didnt get much information from doctors and just need sum advice as i didnt mention i had a 35 day cycle and needed to know if maybe that would have affected the dates i didnt really think it mattered at the time?

sparklingreactions Tue 06-Jan-09 15:50:48

oh and i apologise for the terrible typing in the messsages needed 2 turn a light on hehe how dark is it !!! xx

Lulumama Tue 06-Jan-09 15:51:15

well, if you ahd a scan at 8 weeks, and it said you were 8 weeks or so pregnant, i would believe that scan.

a difference of 4 weeks would make a huge difference with an ealry scan

the difference between a pregnancy of 4 /8 / 12 weeks is huge

it really would have been picked up on

if your other scans also tie in , then you really have to take on board the fact you are not a month further on, especially if fundal height measurement and palpation also concur that you are however many weeks pregnant you are

it is not an issue, your baby will arrive when he/she is ready and there will be signs at birth if he/she is 4 weeks under the expected gestation

Lulumama Tue 06-Jan-09 15:52:38

if you were 12 rather than 8 weeks pregnant at the initial scan, it would have been glaringly obvious

sparklingreactions Tue 06-Jan-09 15:56:29

ino im probably jyst being silly my fundal heights r right to within about .5 of a cm for the early scan. ino im just being paranoid i just heard that babys can be stillborn if left longer than 2 weeks to be induced its my firts baby im a terrible worrier xx

Lulumama Tue 06-Jan-09 16:06:11

babies can, sadly, be still born at term, or early or late. the risk for stillbirth is slightly increased post dates, but still a tiny risk.

your dates etc all seem to tally, so you should try to concentrate on enjoying the pregnancy and make sure you go to all your antenatal appointments and call your MW if you are worried about anything

i honestly think if you were a whole month further on in your pregnancy, it would have been picked up on before the third trimester

sparklingreactions Tue 06-Jan-09 16:13:48

thanx:d iv got antenatal classes this week looking forward to thats hopefully ill have something else to concentrate on then and stop worrying about things that arent there haha. im just abit of a nervous wrek at the moment xx

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