⇨ Weeks 18 to 21: Structural screen
At 18 to 21 weeks, your baby is capable of yawning, kicking, and sucking its thumb. Beyond your normal check-up, this is also the time when you’ll also get an important ultrasound, also known as the “20-week structural scan,” during which the obstetrician will check to see if your baby has any abnormalities in the growth or development, including in the heart, spine, stomach, kidneys, and limbs. It is important to know that while many abnormalities are picked up by this scan, not all of them are. The obstetrician can often tell if you are having a boy or a girl, with about 95 percent accuracy.
If you prefer to wait until the birth to find out the sex of your baby, it’s a good idea to ask the obstetrician not to mention it. Besides, the obstetrician will observe the position of the placenta, the umbilical cord, the amniotic fluid around your baby, and your uterus and your cervix. If your placenta is positioned low in your uterus, the obstetrician will inform you that you have a low-lying placenta. Usually another ultrasound is recommended in the third trimester to ascertain that your placenta has moved away from your cervix.