accuracy of ultrasounds

LittleLams

Registered User
With my first pregnancy, my gynae told me at 12 weeks that it was a boy. At 20 weeks, he said likely that it would be a girl. We had a girl. Now onto my second pregnancy and just had a scan at 16 weeks with the same gynae. He said that it is probably a girl as he could not see anything between the legs. Does anyone have experience with how accurate these scans are?
 
I think they are far more accurate later in the pregnancy.

I went for my "fetal anomaly scan" w/ my eldest when I was about 25 weeks and was told she was most likely a girl. She was.

I went for my "fetal anomaly scan" at about the same time for my second, and he was a boy, front and center. My husband was able to tell from across the room.

But, you still never know for certain until the birth, I suppose.
 
I had a scan at 20 weeks and the Doctor was pretty convinced it was a boy. But I too wondered about the scans accuracy, so when I had a 4d scan at 36 weeks I asked the Doctor again then and with that scan there was no denying its accuracy. Definetly a boy!
Agree with loupou they are more accurate the later in pregnancy you are.
 
Hi

The gender can be determined visually with a quite good accuracy from the 16th week

But anyway it always depends on the position of the baby... and they should never give a 100% probability on the visual basis.

Only the amniocentesis or the birth give a certainty
 
Thanks. With my experience with the "false expectation" the first time around, I am wondering whether i should wait until the birth to find out!!!
 
I found this info when I first learned my doc was giving "80 per cent certainty" predictions at 12 weeks. The conclusion is, it's very accurate even at 12 weeks, if the practitioner is using the right techniques - but of course in some cases they'll be mistaken.

http://www.ob-ultrasound.net/genderfaq.html

On the subject of "early diagnosis of fetal gender", a recent article by B J Whitlow et al, entitled "First trimester diagnosis of gender" which appeared in the Journal: Ultrasound in Obstetrics and Gynecology 1999; 13:301–304 addressed this issue.
This study addresses the question of first trimester diagnosis of fetal gender by assessing the outcome of 447 women who had normal transabdominal ultrasound sometimes complemented with transvaginal ultrasound (26%) when the genitals were not clearly visible. Patients were scanned between 11 and 14 weeks and were referred for assessment of fetal anatomy.
Results showed that the overall success rate of gender identification between 12 and 14 weeks was 80% which is less than invasive karyotyping. In the transverse plane, male fetuses showed a dome shaped genital swelling with a cephalic-directed phallus and females had three or four parallel lines representing the labia. The gender of the fetus did not affect the operator’s ability to assign gender and when assignment was possible gender did not affect the accuracy. The ability to assign gender increased with increasing gestational age.


Another article, Determination of gender - 10 and 14 weeks by Z Efrat et al which appeared in the Journal: Ultrasound in Obstetrics and Gynecology 1999; 13:305–30, reported:

The 172 women were all scanned transabdominally.

....

The phallus was vertical/cranially directed in males and caudally directed in females. At 12 weeks the accuracy of gender assignment was 98.7% and at 13 weeks the accuracy was 100%. There was incorrect assignment of males as females in 3% at 12 weeks and no females assigned as males after 12 weeks.
 
In Aust they will not even try to ascertain the sex of the child at 12 weeks. You have to wait until your 18 week scan.
 
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