42 days (6 weeks) after fertilization, around week 8 of pregnancy
External genital changes in Fetus development
The Ultrasound Angle of the Dangle
9 week old embryo - 11 weeks Pregnant
How big is fetus at 12 weeks pregnant?
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At 12 weeks pregnant the fetus will be about 45 to 50 millimeters (less than 2 inches) CRL (head to butt) length, thats just a little more than the width of two U.S. pennies (one cent coins).
The genital tubercle (nub) area at 12 weeks pregnant will be about the size of a 'pin head'. On ultrasound scans; looking through, layers of skin, womb and amniotic fluid it will be difficult to see.
Waiting until 16 weeks pregnant when the fetus is about three times bigger and gender changes done is a better time for that first 'look'.
Male - 11 week old fetus - 13 weeks Pregnant
|Development of the male external
genitalia is dependent upon dihydrotestosterone which is produced by the
testes. As the genital tubercle is elongating and growing to form the
penis, the urogenital folds which lie on either side of the urogenital
membrane begin to move towards each other forming a groove, this is
known as the urethral groove. The urogenital folds fuse together on the
ventral side of the developing penis, enclosing what will now become the
|In the absence of the SRY gene, of the Y chromosome, a female embryo will develop. |
The development of the female external genitalia is promoted by the presence of estrogen and other hormones within the maternal system. The phallus described earlier continues to grow to become the clitoris. Meanwhile, the urogenital folds are developing into the labia minora. Their development is similar to that in the male. They grow up along side the phallus except that in the female, they fuse only at the most posterior aspect (bottom) to form the frenulum labiorum pudendi or fourchette.
The labioscrotal folds continue to grow as well, fusing at their most posterior and anterior portions to form labial commissures. The portions of the labioscrotal folds which do not fuse form the labia majora.
The HOT topic on pregnancy forums around the world is...
The angle of the dangle topic
A. At around 12 weeks a sonographer may make a 'best guess' as to the gender of baby from a scan, but this can, and will be, only a little better than 50/50.
On ultrasound, if your baby is cooperating and is positioned in a favorable way, fetal sex can be determined during a scan when the fetus is about 12 weeks (about 14 weeks after LMP).
Angle of the dangle
The determination is made by studying the angle between the genital 'bump' and the direction of the lower portion of the spine. The following images are not typical and intermediate forms do exist, establishing gender can sometimes be difficult.
How accurate are routine first trimester scans for fetal gender determination.
Ultrasound gender study - Objective study to assess the accuracy of fetal gender determination at a routine first trimester scan for detailed assessment of anatomy and nuchal thickness measurement.
In the study the angle of the genital tubercle was used to assign fetal gender. At 11 weeks there was an error rate of 50% and only 14 of every 100 was 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.
The gender prediction test result is easy to read! The control test window will change color to either pink (Girl) or blue (Boy).Enjoy - First class