For those of you wondering how it is possible to find out the sex of the baby so early, here is an explanation.
Details of ‘Angle of the 30 degrees’ study
The fetal gender was assigned as male if the angle of the genital tubercle to a horizontal line through the lumbosacral skin surface (lower portion of the spine) was greater than 30 degrees and female when the genital tubercle was parallel or convergent (less than 10 degrees) to the horizontal line.
WHEN LOOKING AT THESE PICTURES LOOK AT THE BLUE/PINK ARROW. THEN RIGHT UNDER IT, THE 1ST YELLOW ARROW IS OVER THE “GENITAL TUBERCLE” OR THE BABY’S GENITALS. AT THIS AGE BOTH BOYS AND GIRLS LOOK LIKE THEY HAVE A PENIS, BUT IT DEPENDS ON THE ANGLE OF THE GENITAL TUBERCLE. WHICH IS WHY YOU NEED A VERY EXPERIENCED ULTRASOUND TECH, AND THEIR GUESS IS ONLY 88% CORRECT AT THIS POINT. SO IT IS MORE FOR FUN, WE WON’T BE CHANGING THE NURSERY TO BLUE UNTILL WE GET TO 16+ WEEKS.
(Sorry for the caps I can’t use fancy formatting on my iPad)
Female gender (See the angle of the pink arrow)
In some of the study groups, when the angle of the genital tubercle was an intermediate angle of 10 to 30 degrees the fetal gender was not determined.
Out of a total of 1619 pregnancies; gender was assigned and confirmed in 1424. The table below shows the results in so far for accuracy of fetal gender prediction at a routine first trimester scan.
Results of ‘Angle of the 30 degrees’ studies
Weeks of gestation 11 weeks 12 weeks 13 weeks 14 weeks
Ability to assign fetal
gender % age group 68% 88% 94% 98%
fetal gender 50% 84% 90% 94%
Male fetuses incorrectly
assigned as female 41% 13% 8% 5%
Female fetuses incorrectly
assigned as male 9% 3% 2% 1%
Gender correct from
100 baby scans 34 80 85 92
Prenatal gender assignment by ultrasound has a high accuracy rate at 12 to 14 weeks. At 11 weeks there was an error rate of 50% and only 14/100 assigned correct male gender. In the male fetuses after 12 weeks, there was a significant increase in the angle of the genital tubercle from the horizontal. The accuracy of sex determination increased with gestation.