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OB ultrasound

33 studies11 challenges

Where is the pregnancy, how old is it, is it well: the questions each image answers, in the order the clinic asks them. Every image opens with how to read it; switch to Practice when you are ready to be tested.

Transabdominal ultrasound of the uterus with heterogeneous echogenic material low in the uterus near the cervix and an empty fundusTransabdominal, sagittal · 15 weeks

OB ultrasound · Early pregnancy loss

Bleeding with tissue passed, second trimester

Diagnosis

Incomplete miscarriage with retained products in the cervical region

Normal against abnormal

The plane, and which way is up

Transvaginal, sagittal: the probe is in the vagina, so the top of the screen is nearest the probe (the cervix and lower uterus), the fundus is deeper on the screen, and the bladder is at the upper left. Transabdominal sagittal is the reverse: the bladder is at the top of the screen and the uterus lies behind it.

Look for, in order

  1. Is there a sac, and what is inside it? An empty sac with a mean diameter of 25 mm or more (transvaginal) is anembryonic.
  2. If there is an embryo, measure the CRL and look for cardiac activity for at least 30 seconds; no heartbeat at a CRL of 7 mm or more is failed pregnancy.
  3. After bleeding: is the cavity empty, is there retained tissue (heterogeneous echogenic material, often with flow), or a sac still present?
  4. Below the thresholds, do not call it: repeat in 7 to 14 days.

What normal looks like

A viable pregnancy has cardiac activity appropriate to its age; the criteria for failed pregnancy are deliberately strict so that no viable pregnancy is ever ended on a scan.

Trap. Dates are often wrong; a small empty sac is usually early, not failed. Wait, rather than diagnose loss on one scan below threshold.

Describe it in this order

  1. The plane and the approach (transabdominal or transvaginal)
  2. Location of the pregnancy: in the uterus or not
  3. Number: singleton or multiple, and chorionicity
  4. Viability: cardiac activity
  5. Dating or growth: the measurement that fits the stage
  6. Fetal anatomy, placenta, cord, fluid, cervix, as the stage allows
  7. Adnexa and free fluid
  8. Then, and only then, the impression

Findings

  • Fundus and body of the uterus empty
  • Heterogeneous material in the lower uterus and cervical region

What it means for the patient

An incomplete miscarriage on ultrasound is retained heterogeneous tissue with an open or filling cervix; the fundus is empty. The management options (expectant, medical, surgical) depend on bleeding, haemodynamic stability, infection and the patient's preference. Rh status is checked and anti-D given where indicated.

Framework: ACOG, Practice Bulletin 200: early pregnancy loss (2018).

OBGynSpace Tutor

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