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How to perform and interpret a first trimester transabdominal point-of-care ultrasound
  1. Sally Graglia1,
  2. Aaron Kornblith2
  1. 1 Department of Emergency Medicine, University of California San Francisco, San Francisco, California, USA
  2. 2 Department of Emergency Medicine & Pediatrics, University of California, San Francisco Medical Center, San Francisco, CA, USA
  1. Correspondence to Dr Sally Graglia, Emergency Medicine, University of California San Francisco, San Francisco, California, USA; sally.graglia{at}

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Case presentation

A previously healthy 31-year-old gravida 1, para 0, presents to the ED for the evaluation of vaginal bleeding. The patient took a home pregnancy test that was positive and notes that her last menstrual period was 8 weeks prior to her presentation to the ED. The pregnancy is spontaneous and desired; however, she has had intermittent vaginal spotting, soaking four pads since yesterday. She takes a prenatal vitamin but has no other prescribed medications.

On physical examination, she is well appearing with normal vital signs, including a blood pressure of 135/94 mm Hg and heart rate of 84 beats per minute. Her abdomen is non-tender with normal bowel sounds without rebound or guarding. On pelvic examination, her cervical os is closed with a small amount of blood in the vaginal vault.

Intravenous access was obtained; laboratory evaluation shows a normal haemoglobin of 13.3 g/dL, platelets of 208 k/uL and an international normalised ratio of 1.0. Her blood type is O+, and she has a beta-human chorionic gonadotropin of 147 411 mIU/mL. A first trimester abdominal point-of-care ultrasound (POCUS) was performed to evaluate for the presence of an intrauterine pregnancy.

What are the indications for performing a first trimester POCUS?

The primary indication for performing a first trimester POCUS is to evaluate for the presence of an intrauterine pregnancy.1 In the first trimester of a spontaneous pregnancy, the confirmation of an intrauterine pregnancy on ultrasound makes an ectopic pregnancy sufficiently unlikely since the rate of heterotopic pregnancy is very low.2 In contrast, in an assisted pregnancy or a pregnancy resulting from in vitro fertilisation, the risk of a heterotopic pregnancy increases from as low as 1/10 000 to as high as 1/100 pregnancies.2–4 Any patient who is undergoing assisted fertility warrants additional work-up for the presence of a heterotopic pregnancy despite a confirmed intrauterine pregnancy.2–4

Which transducer is best suited for performing a first trimester transabdominal POCUS?

The location of a pregnancy may …

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  • Handling editor Simon Carley

  • Contributors I was the primary author in this manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.