According to Kinnear, they will examine the baby's heart rate as well as your cervix to ensure that it is clear of the placenta, closed, and lengthy. Cervical length is significant since a shorter cervix increases your chances of premature labor. A technician will inspect for it. During this part of the scan, the mother's belly will be exposed to allow the technician to view her uterus. They will also measure the thickness of your uterus to make sure it isn't too thick (more than 5 inches) or too thin (less than 3 inches). The reason for this measurement is so they can tell if you are at risk for preterm delivery or not. Women with a previous history of preterm birth have their uteruses checked regularly to make sure they don't get back into normal ranges too soon after showing signs of distress. This type of scan is useful in identifying women who are at risk for preterm delivery so that precautions can be taken to avoid complications.