the midwife gives you a due date from your last period date however a date scan is more accurate as they measure the size of the baby but can be a week or so out thats why people go overdue by 10 days, hope this helps as im not a specialist xx Hi Vicky Are you worried about a dating scan you have had or are due to have Vicky? I am pretty sure ill only be 8 weeks pregnant with the date i have been given. I was given a date, but had to have an internal scan.
Generally scans are very accurate, but they are not 100% perfect, so there is always a small margin for error (generally up to about a week, but this varies). It turned out to be very accurate as my daughter was born 9 hours after that date! I had a scan at 6 weeks (was on honeymoon at the time and fainted in Turkey) the date they gave me was 19th lo was born 20th however my 12week scan due date was 14th !
we have found three ultrasound dating formulae that seem to be associated with small systematic and random errors when used for dating both at 12–14 and 15–20 weeks (mul et al.
(1982)14), or they considerably overestimated gestational age at both early and late dating (hadlock et al.
5 ½ weeks gestation means 5 ½ weeks from the first day of the last menstrual period, which is usually about 3 ½ weeks from the date of conception (confusing, isn’t it!
) the fetus is clearly seen on trans-vaginal ultrasound and the heart beat can be seen at this early stage (90 to 110 beats per minute under 6 to 7 weeks, then 110 to 200 beats per minute as the baby matures).
Your midwife may recommend an early scan at between six weeks and 10 weeks if you have experienced bleeding.
You may also be offered an early scan if you've had a previous miscarriage.
Ask your GP if you want the reassurance of an early scan. The scan's main purpose is to work out accurately how many weeks pregnant you are and estimate your due date.You may have calculated the length of your pregnancy from the first day of your last menstrual period (LMP).This is even though you don't actually conceive until 14 days after your LMP, or later than this if your cycle is longer than 28 days.For transvaginal ultrasound you can have an empty bladder Dating scans are usually recommended if there is doubt about the validity of the last menstrual period.For example if you a tiny sac can be seen in the uterus, but the baby and its heart beat may not be detected yet.For most mums-to-be, the first scan will be a dating scan at between 10 weeks and 13 weeks plus six days of pregnancy.However, the timing of your first scan will also depend on how your pregnancy is going, and where you live.the baby and its heart beat can be detected relatively easily with trans-abdominal and trans-vaginal examination.This is presuming that the pregnancy is actually at this stage of development.Most dating scans are done with a trans-abdominal transducer and a fullish bladder.If the pregnancy is very early the gestation sac and fetus will not be big enough to see, so the transvaginal approach will give better pictures.from 6 to 11 weeks gestational age, the fetal crl grows at a rate of about 1 mm per day.accuracy of plus or minus three days at seven weeks; this test can be.is apparently a distinct difference in the attitude towards routine ultrasound screening between the europeans and the americans.