A 25-year-old female presented to the ED with vaginal bleeding and lower abdominal cramping. She had taken a pregnancy test 2 weeks prior to being seen in the ED, and it was positive. She had one prior pregnancy that went to term and then had to have a cesarean section for failure to progress. The bleeding had started the day she presented to the ED, and she reported that it was dark with clots. She denied a history of miscarriage or ectopic pregnancy.


Initial VS: BP 115/66, HR 78, RR 16, SpO2 100% on RA


Physical exam revealed a soft, non-tender, and non-distended abdomen. Pelvic exam revealed a mild amount of blood in the vaginal vault with a closed external cervical os.


Urine pregnancy test done in the ED was positive.


A bedside transvaginal ultrasound was done to try to confirm an IUP. Here is the first clip:

What do you see?


You can see that the endometrial stripe, closer to the fundus, appears thickened and appears to have some debris, either clot or other products, present. If you look closer to the cervix, you can see what appears to be a gestational sac. To the novice this could look like a pregnancy that is in the process of spontaneously aborting. Look even closer, however, and you can also see the C-section scar in the uterus. It looks like the gestational sac is attaching to the scar. What!? Here is a still shot pointing out structures:

cearean scar




This abnormality caught the eye of the sonographer, and a zoomed in view was obtained:

It appears there is a gestational sac present without an obvious yolk sac.


The sonographer also obtained transverse views of the uterus:


In the first clip you can see the fundus moving down toward the cervix. In the second clip you can see the gestational sac to the left of midline, outside of the endometrial stripe; further raising the suspicion of a C-section scar ectopic pregnancy.


Another good way to confirm that this is not just a pregnancy on its way out of the uterus is to put color Doppler flow over the gestational sac. See below:

See how it lights up like a “ring-of-fire.” This means that it is still highly vascular and attached to the uterine wall. An incomplete abortion would not do that.


Obstetrics was consulted from the ED. They wanted to see the patient back in 2 days for follow-up. When she presented for follow-up, she had a repeat ultrasound that showed the gestational sac had passed spontaneously.


If a pregnancy implants in the myometrium in early pregnancy, it can cause uterine rupture and rapid, profuse bleeding as the pregnancy progresses. The incidence of a cesarean ectopic is thought to be 1:1,800 to 1:2,216 of all pregnancies. The imaging modality of choice is ultrasound. Transvaginal ultrasound has a sensitivity of 84.6% in detection of cesarean ectopics. These pregnancies most often are misdiagnosed as either cervical ectopics or incomplete abortions. When detected early, treatment is variable and is usually based off of symptomatology. Treatment options range from expectant management, as in our case, to D&C.


Bottom Line: In someone with a prior c-section, make sure that what you call an incomplete miscarriage is not actually a cesarean ectopic!




  1. Mackesy MM, Chick JF, Chauhan NR, Mandell JC, Khurana B. Cesarean section scar ectopic pregnancy. J Emerg Med. 2014;46(5):685-686.
  2. Rotas MA, Haberman S, Levgur M. Cesarean scar ectopic pregnancies: etiology, diagnosis, and management. Obstet Gynecol. 2006;107(6):1373-1381.
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