With ultrasound, a fetal heart can be seen beating as early as 5 or 6 weeks into the pregnancy. Ultrasound can detect fetal motion. You will be asked to drink a lot of water before an ultrasound examination. Your doctor can use ultrasound in many ways in relation to your pregnancy. When your bladder is empty, your uterus is harder to see because it is farther down inside the pelvic bones.
Bones disrupt ultrasound signals and make the picture harder to interpret.
With your bladder full, your uterus rises out of the pelvis and can be seen more easily. The bladder acts as a window to look through to see the uterus and the fetus inside. The ultrasound vaginal probe, also called the transvaginal ultrasound, can be used in early pregnancy for a better view of the baby and placenta. A probe is placed inside the vagina, and the pregnancy is viewed from this angle. Some couples ask for ultrasound to determine whether they are carrying a boy or girl.