Empty gestational sac without fetal pole. Need three views (length, width and height) to calculate MSD. An empty gestational sac with a MSD of ≥25 mm is diagnostic for an anembryonic pregnancy. Early pregnancy loss occurs in approximately 10-20% of clinically recognized pregnancies.
Note that this gestational sac with fetal pole is not intrauterine (no cervix is seen in the same plane). Ectopic pregnancy occurs in approximately 1-2 % of pregnancies.
|Free Fluid in Cul-de-Sac
Longitudinal view of the uterus. Note the presence of anechoic (dark) fluid in the posterior cul-de-sac. This may be a finding consistent with blood from an ectopic pregnancy or uterine perforation.
|Gestational trophoblastic disease
Image of complete mole (no embryo). A complete mole has a cystic intrauterine mass with no distinct gestational sac with yolk sac or fetal pole. Often has a swiss cheese, snowstorm, or moth-eaten appearance on ultrasound. Refer for inpatient management > 12-week size due to increased bleeding risk. Gestational trophoblastic disease occurs in approximately 0.1% of pregnancies.
Uterine fibroids are a common pelvic tumor that may enlarge or distort the cervix or uterine cavity, presenting technical difficulty. Ultrasound can help identify the size, location, and orientation to the pregnancy.
Images AIUM 2018 and 2020