A transvaginal ultrasound is a type of pelvic ultrasound used by doctors to examine female reproductive organs. This includes the uterus, fallopian tubes, ovaries, cervix, and vagina. “Transvaginal” means “through the vagina.” This is an internal examination.
During this procedure, a doctor will insert an ultrasound probe about two or three inches into your vaginal canal.
The entire test takes about 30 to 60 minutes.
A transabdominal ultrasound is an alternative procedure option.

There are many reasons a transvaginal ultrasound might be necessary, including:
an abnormal pelvic or abdominal exam
unexplained vaginal bleeding
pelvic pain
an ectopic pregnancy (which occurs when the fetus implants outside of the uterus, usually in the fallopian tubes)
infertility
checking for cysts or uterine fibroids
checking for proper placement of an IUD
Your doctor might also recommend a transvaginal ultrasound during pregnancy to:
monitor the heartbeat of the fetus
look at the cervix for any changes that could lead to complications such as miscarriage or premature delivery examine the placenta for abnormalities
identify the source of any abnormal bleeding
diagnose a possible miscarriage