Ultrasound scans are very useful to check the child's development and well-being in the uterus. They are non-invasive tests that have no negative impact on the fetus, so as many can be performed as your doctor considers necessary.
The Social Security standard is a minimum of three ultrasounds (one per trimester), although more can be performed if necessary. In private healthcare, ultrasounds tend to be more frequent. Some doctors perform an ultrasound every month. An ultrasound also tends to be used to confirm the pregnancy.
In all the ultrasound scans, the size of the baby is measured, as is their movements and heartbeat, the amount of amniotic fluid and the position of the placenta, and the likely due date is calculated.
First trimester ultrasound: Around week 12
This ultrasound scan, which is usually vaginal, is to check if there is more than one baby, and to measure the nuchal fold of the fetus, to assess the risk of chromosomal abnormalities.
Second trimester ultrasound: At week 20 of gestation
This is to observe the internal organs of the fetus to check that the baby is developing well. You can usually discover the gender of the baby, if it is in the right position.
Third trimester ultrasound: Around week 34
This is to once again assess the growth of the fetus and look at its position for labor. If it is a breech position, another ultrasound is often performed to check whether the baby's head has engaged.