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the EDD is the estimated date of delivery, with both of my children the edd was not correct. my first was born a week after the edd which was the date of conception plus 40 weeks. my second was born 10 days prior to the edd but i also had 4 different edd.

Estimated Date of Delivery is just that, Estimated. A baby can be born from 3 weeks before up to 2 weeks after with no problems.

With my first, his scan EDD was 10 days later than my period EDD and he was born on the scan EDD.

Second time around (twins) the scan and period EDD were the same but I was induced 4 weeks before with pre-eclampsia.

The only EDD that is accurate from an ultrasound is one done in the first trimester. The earlier the ultrasound is performed, the better. We measure what is known as the crown-rump length (the measurement from the top of the head to the baby's backside), and this measurement is the most accurate in predicting an EDD. First trimester ultrasounds are typically accurate within a week of how far along a baby actually is. Second trimester ultrasounds are up to two weeks off; and third trimester ones are up to three weeks off. What we are measuring, though, is how far along the baby really is--not when the baby will be born. As someone else mentioned, a due date is only an estimate--and only 5% of women actually deliver on their due date.


Dr. B.

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โˆ™ 2015-07-16 18:06:23
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Q: Is an ultrasound EDD accurate if your period does not last normally seven days?
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Related questions

Can your last menstrual period show twenty three weeks but your ultrasound show twenty seven weeks which is more accurate?

ultrasound is more accurate. Measurments of the fetus are made during ultasound that give a more accurate gestational age

Is seven days before a missed period to soon to take a pregnancy test?

Taking a pregnancy test seven days before a missed period won't be accurate.

How long can a seven week baby stay dead in its mother's womb?

Normally it will come out in a monthly period if it is dead.

If an ultrasound estimates that you are seven weeks pregnant could it be off by a week?

Not really. Babies grow at pretty precise rates and therefore conception is pretty easy to answer at this early in your pregnancy. You are more likely to have your dates mixed up or that you conceived at a different time than you thought. Yes the date could be off a bit but ultrasound dates are usually pretty clear and accurate on dating embryos. Its all down to the measurements taken of the embryo and last period etc, that give a estimate of the conception date. When an ultrasound shows you are 7 weeks pregnant it actually means you are 5 weeks from conception. Pregnancy is on average 40 weeks from the start of the last period. This is because in the days before ultrasound this was the only date we knew. You don't actually conceive until 2 weeks after this date.

How do you define a workweek?

A workweek is part of the seven-day period in which work is normally performed usually from Monday to Friday from 9 A.M. to 5 P.M.

If an ultrasound at seven weeks on October 25 predicts a due date of June 3 when did you conceive?

When the doctor counts you as 7 weeks, they are counting from your last period. I figured if the ultrasound says 7 weeks, that is from around sep. 7th, the 1st day of your last period. meaning between sep. 18th thru sep. 24th could have got you pregnant. Likely the 21st. However an ultrasound of 7 weeks on 25th October gives you a due date of 13th June not the 3rd. See the Related Link for "conception-calculator" to the right for more.

Is it normal to have an ultrasound at seven weeks and see no sac and no heartbeat?

I'm not in the medical field, but with my pregnancy at 6w 2d the technician could see the sac, but no baby. She then did an internal ultrasound, and it was then visible with a heartbeat.

What is the 28 day cycle?

first week, no period. seven days. second week, no period. seven days. third week, no period. seven days. fourth week, period. seven days. it can vary...

Did Kate gosselin have septuplets and one die?

At the first ultrasound, there were seven but shortly after the seventh stopped developing and there were six.

How early can you see a heartbeat on an ultrasound?

well, i seen the flicker on a monitor, which is the baby's heartbeat..and I'm seven weeks.

What does a pelvic ultrasound reveal about a fetus?

In early pregnancy (about five to seven weeks), ultrasound may determine the size of the fetus to confirm the suspected due date, detect multiple fetuses, or confirm that the fetus is alive (viable).

How many days before periods does you know that U are pragnent?

Seven Days after Ovulation period Seven Days after Ovulation period

Ive been on the birth control pill for about a month now how long should your period be normally lasting for?

For the seven days you supposed to take the sugar pills. Sometimes maybe a day or two after.

What is radium's period number?


If an ultrasound at week seven shows a low heartbeat of 70 can you still give birth to a healthy baby?

Yes, absolutely.

What happens after seven years after a girl has her period?

Nothing happens seven years after a girl has her period. There's nothing specific about this length of time.

What is a seven piece bathroom?

they normally consist of 5 but if you want they say a seven piece is called a tangram.

Does your stomach get stiff if you are seven weeks pregnant?

Not normally that early

How do you arouse your girlfriend who is seven weeks pregnant?

Arouse her normally...

Can you be as young as seven to get your first period?

It is VERY rare to get a period at 7 but it could happen.

What is the gestation period for a porcupine?

Seven months.

What is the gestation period for a badger?

seven weeks

Im sure im 5 weeks pregnant not 7 and i had 2 ultrasound they both show sac but no baby is it too early to see the first 1 was at 3 weeks and then at 5 but according to the doctor im 7 weeks?

If you are 7 weeks from your last period, you are seven weeks pregnant, 3 weeks pregnant is before you miss a period and you would not have a scan then. If you are seven weeks and there is no sign of a fetal pole it appears that the embryo may not have developed and you will miscarry soon, I am sorry.

Are there any ultrasound technician schools in SC ?

South Carolina has many ultrasound technician schools, both online and on-campus. Depending on which program you are interested in, there are at least seven schools that you can consider. A helpful website to visit to view each school and their programs is

Your period lasts every 6 days when you start?

no your period can be anywhere from 2 to seven days

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