Is an intrauterine pregnancy (IUP) (defined as yolk sac or fetal pole) present?
Abdominal or pelvic pain
Suspected ectopic pregnancy or risk factors for ectopic pregnancy
Vaginal bleeding
Unexplained syncope, or hypotension
Pelvic mass
CONTRAINDICATIONS
Absolute: None
Relative (transvaginal approach): Recent major pelvic surgery
CONSENT
Get verbal or written consent for the procedure, except in extremis situations
RISKS
No documented harmful effects on the fetus or the mother due to ultrasound exposure
LANDMARKS
Transabdominal
Have the patient lie supine
The bladder should be full in order to have an adequate acoustic window
Use a standard curved 3.5- to 5.0-MHz probe to scan the lower abdomen
Place the probe on the anterior abdominal wall, at the level of the symphysis pubis
For advanced gestations, place the probe more proximally
Transvaginal
Insert the probe into the vaginal canal
The uterus is midline, posterior to the bladder and anterior to the rectum (FIGURE 44.1)
The right and left ovaries are lateral to the uterus and anteromedial to the right and left iliac vessels
Anteroflexed uterus 90% and retroflexed in 10%