Doctor insights on:
How Accurate Are Dating Scans
How accurate is a dating scan saying im 9 weeks. Had 2 a week and a half apart and both said same things. 1st-due date jan 27th other, jan 26th 2016.
Ultrasound: dating is generally accurate by +/- 8% in days, so at 9 weeks it is accurate to approximately +/- 5 days. ...Read more
Very: It has a 5-7 day margin of error. It is quite accurate. ...Read more
How accurate are early dating scans mine came back 6weeks 5days due 23 October and my LMP was on 13/1/14 due date 20th October ?
Conception: Early scans are the most accurate and most used way to determine conception and due dates. You can verify all you need to know about your pregnancy yourself on the internet. The tools are readily available. Your baby was conceived on 1/30/2014 from sex that occurred 1/25/2014 to 1/30/2014. You can verify this here: http://www.babymed.com/conception-calculator. ...Read more
OK: Dating via ultrasound decreases in accuracy with increasing fetal age. ...Read more
Should be ok: Dating ultrasound scans have good accuracy at 8-11 weeks, so one done at 13 weeks should still be reliable. Dates by ultrasound are always estimates. ...Read more
How accurate is 12 week dating scan? Babies crl measured 5.6cm, the doctor said this makes me 12w 1 d pregnant? Do this sound right?
Sounds right : That sounds right. 12 week sonograms have about a 5 day margin of error. ...Read more
Why did my 9 week scan change my lmp date? Did i ovulate late. Is that what happend? Is dating scan at 9 weeks accurate to find ovulation?
Scan likely accurate: A 9 week scan should be accurate at getting our best idea of a due date, although it is within normal range to deliver anytime between 37 and 41 weeks....so even our best guess isn't that "accurate". And yes, if the scan made your due date later, then you likely ovulated later. Ovulation time can vary even with fairly regular periods. ...Read more
Does my due date from dating scan at 9 weeks give an accurate day of when i ovulated. My lmp was 7 days earlier than dating scan said it was.
My dating scan 2 weeks ago showed gest sac =5w1d. No fhr.Today scan showed crl 4.4mm =6w1d, sac 13.4mm, fhr 112. Is this reassuring ?Need f/ u scan?
Everything: Sounds encouraging and the embryo is growing. Consult with your obstetrician about the need and timing of future ultrasounds. ...Read more
my dating scan 1st August 2014 dated me 12w 5days who is the dad? the one on the 20th april or the second on the 29th april til middle of may?
Second one: Thirteen weeks is a trimester, or 91 days, which puts your date if conception around the 3rd of May. Since there is an error factor of +/- 5d - 2weeks, you will probably need to do paternity testing, since within this error factor, either one could be the dad, within the error if the testing technique. Dad #2 is the front runner in this calculation, but can't rule out #1 by dates alone ...Read more
I had a dating scan yesterday I am 4w3d. I didn't feel nauseous that much and my nips still are sensitive but not as much can symptoms come and go?
Yes: Absolutely! It's early, so symptoms will wax and wane for a couple of weeks then set in. Every woman's experience is different ...Read more
Much more than: Later in gestation. First trimester ultrasound is most accurate at estimating gestational age within 5-7 days (depends on the center). It trails off after that. General rule: 2nd trimester scans for dating are +/- 14 days and 3rd trimester is the least accurate (+/-21 days). ...Read moreSee 1 more doctor answer
Can 12 week dating scan be off by 2 weeks? Could a 10 week gestational age fetus measure as big as 5.6cm?
Yes: Ultrasound scanning is related to the skill of the sonographer. Typically a 10 week scan has three days of error built in when the test is performed vaginally. There is more error with an abdominal ultrasound. Average crown rump length at ten weeks is approximately 3-4cm. ...Read moreSee 1 more doctor answer
Wouldn't a fetus at a 14 week dating scan be seen if it was bigger or smaller be detected in determining due date?
Being pregnant: At fourteen weeks, if a female was pregnant, a fetus would be observable. ...Read more
20 week anatomy scan gave due date 3 days earlier than dating scan done at 9 weeks. which due date should i go by? Are they both wrong?
The ultrasound: A second trimester US is much less reliable than a first trimester one. In this case, they are very consistent which makes your dating very reliable. Go with the 9 week ultrasound date. You did not mention your LMP, but if it is also consistent with the 9 week sono, that makes your dates even more reliable. ...Read more
Does everyone ovulate on day 14? Is this why my dating scan changed my lmp 7 days later than it was? Because i didnt ovulate on day 14??
Which male could be the dad. 20th april or beginning of may as dating scan dated from 3rd may but baby was born 4th feb 4 day early from EDD?
Either guy could be: From April 20 to May 3 is 2 weeks, which can be too close to call. It doesn't matter when the baby is born, if the original dating ultrasound was within the reliable dating time earlier in pregnancy. One can do this the old-fashioned way, meaning the father is the guy the woman married... and live happily ever after. Or, if one must know exactly, one can just save up for the cost of the DNA tests. ...Read more
If my dating scan gave me the due date 21st September is there any way at all I conceived on the 9th jan or after ? Could it be out that much?
Very probable: Ultrasound scans have a plus/minus error of two weeks, however your dates line up for that conception date with a EDC of 9/21/16. ...Read more
Will dating scan at 9 weeks give a later lmp than actual lmp if i ovulated later than day 14?? Should i use dating scan to find ovulation date?
Should i go by lmp or dating scan at 9 weeks? Dating scan changed lmp date to 6 days later than it actually was. Is this because i ovulated late?
That's the same date: In pregnancy dating, all dates for natural pregnancies are estimates (plus or minus a week). That means 6 days earlier than a presumed date, or the presumed date, or 6 days after the presumed date, ARE ALL THE SAME DATE. That's how it works. They are the same day. But, if a woman only had sex ONE time, she knows her conception was likely 1-5 days after that. Dating scan at 9 weeks is accurate. ...Read more
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