This transabdominal pelvic ultrasound demonstrates a sagittal view of the bladder and uterus. The uterus is empty, and there is a moderate amount of free fluid in the Pouch of Douglas and superior to the uterus.
Obstetrics and Gynecology (OBGYN) was consulted and the patient went to the operating room (OR) for concern for ruptured ectopic pregnancy. The patient was found to have 400 cc of hemoperiteum with a dilated left fallopian tube near a tribally aborting pregnancy. The left ovary was slightly enlarged with what appears to be a subcentimeter ovarian cyst but overall normal appearing left ovary with a normal right fallopian tube and ovary.
Ectopic pregnancy is defined as a pregnancy which has been implanted in a location other than the uterus.Most ectopic pregnancies are in the fallopian tubes (96%), but ectopic pregnancies can also be cervical, interstitial or cornual, intramural, ovarian, or abdominal. 1
Ectopic pregnancies can present with first trimester vaginal bleeding or abdominal pain.2 Some ectopic pregnancies can be asymptomatic.
Reported incidence of ectopic pregnancy ranges from 2% – 13%.3,4
Pelvic inflammatory disease (PID), previous surgical manipulation of fallopian tubes, or previous ectopic pregnancy are risk factors for ectopic pregnancy.7 However, half of women with a diagnosed ectopic pregnancy do not have known risk factors.7
Generally, the presence of an intrauterine pregnancy adequately excludes the presence of an ectopic pregnancy. However, an astute clinician must always consider the possibility of a heterotopic pregnancy (an ectopic pregnancy occurring at the same time as an intrauterine pregnancy). In spontaneous contraception, the reported rate of a heterotopic pregnancy is 1/30,000 patients; in assisted contraception, 1/100 patients will have a heterotopic pregnancy.3
Being familiar with the normal progression of a pregnancy can help providers care for patients with a possible ectopic pregnancy. The first sign of pregnancy is the gestational sac, followed by a yolk sac, a fetal pole, and cardiac activity. While the earliest sign of pregnancy is a gestational sac, this finding in isolation should not be viewed as a definite intrauterine pregnancy. Intrauterine fluid can be seen with ectopic pregnancy, producing this pseudogestational sac. The first definitive sign of intrauterine pregnancy is a yolk sac.6
Cardiac activity can usually be visualized at 6-7 weeks of gestation transabdominally and at 5-6 weeks of gestation transvaginally.6
Traditionally, either the curvilinear is used transabdominally or the endocavitary probe is used transvaginally in the evaluation of the uterus for the presence of an intrauterine pregnancy. In appropriate patients, one study suggests that use of the linear probe can be used in early pregnancy to diagnose intrauterine pregnancy and avoid the time delays and patient discomfort of obtaining a transvaginal ultrasound.5,8
Bouyer J, Coste J, Fernandez H, Pouly JL, Job-Spira N. Sites of ectopic pregnancy: a 10 year population-based study of 1800 cases. Human reproduction (Oxford, England). 2002; 17(12):3224-30. [pubmed]
Alkatout I, Honemeyer U, Strauss A, et al. Clinical diagnosis and treatment of ectopic pregnancy. Obstetrical & gynecological survey. 2013; 68(8):571-81. [pubmed]
McCarty, Matt. “Ectopic Pregnancy.” Core EM. NYU Langone Health, 7 June 2017. Web. December 19, 2018. [web]
Hahn SA, Lavonas EJ, Mace SE, Napoli AM, Fesmire FM, . Clinical policy: Critical issues in the initial evaluation and management of patients presenting to the emergency department in early pregnancy. Annals of emergency medicine. 2012; 60(3):381-90.e28. [pubmed]
Avila, Jacob. “Linear probe in early pregnancy.” 5 minute sono. 16 June 2016. Web. 19 December 2019. [web]
American College of Emergency Physicians. “Tips and Tricks: First trimester pregnancy ultrasound.” ACEP. 1 August 2018. [web]
Barnhart KT. Clinical practice. Ectopic pregnancy. The New England journal of medicine. 2009; 361(4):379-87. [pubmed]
Tabbut M, Harper D, Gramer D, Jones R. High-frequency linear transducer improves detection of an intrauterine pregnancy in first-trimester ultrasonography. The American journal of emergency medicine. 2016; 34(2):288-91. [pubmed]