Introduction:
During the first trimester of pregnancy, evaluation for complaints of lower abdominal pain or vaginal bleeding should include an assessment for ectopic pregnancy. Bedside pelvic ultrasound to detect an intrauterine pregnancy (IUP) can speed this evaluation. When an IUP is visualized, ectopic pregnancy can be ruled out (unless there is suspicion for heterotopic pregnancy). Ectopic pregnancy cannot be excluded in a pregnant patient without a definitive IUP on ultrasound.
Although a double decidual sign and gestational sac have been described in the obstetrics and radiology literature as the earliest signs of a true IUP, the double decidual sign is inconstant and many false positives exist. It is difficult to appreciate the difference between a true gestational sac and a pseudogestational sac (a collection of fluid or blood in the uterus which mimics early pregnancy but is NOT an IUP). Thus, most emergency physicians will not define a true IUP until a yolk sac is seen.
Focused Question:
- Is there an intrauterine pregnancy?
Required Views:
1. Transverse view of uterus (Transabdominal approach)
| Probe position | Image |
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| Notes | |
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| Positive studies demonstrating IUP (click to enlarge) | |
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2. Longitudinal view of uterus (transabdominal approach)
| Probe position | Image |
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| Notes | |
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| Postive studies demonstrating IUP (click to enlarge) | |
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3. Transverse or coronal view of uterus (Transvaginal approach)
| Probe position | Image |
 Transvaginal ultrasound approach- transverse |
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| Notes | |
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| Positive studies demonstrating IUP (click to enlarge) | |
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4. Longitudinal view of uterus (Transvaginal approach)
| Probe position | Image |
 Transvaginal ultrasound approach- longitudinal |
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| Notes | |
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| Postive studies demonstrating IUP (click to enlarge) | |
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