Scar implantation pregnancy progressing to placenta percreta

Case contributed by Dr Alexandra Stanislavsky


PV Bleeding in early pregnancy

Patient Data

Age: 35 years
Gender: Female

A single intrauterine gestational sac is demonstrated, containing a single embryonic pole and yolk sac.

CRL 17mm ( 8 weeks 0 days).
Cardiac activity: Present, heart rate 162 bpm.

Perigestational hemorrhage present in the fundal region, measuring 39 x 17 x 20 mm (7 ml).

The gestational sac is centered in the lower uterine segment, with thickened decidua within the Cesarean scar nidus, and a thinned overlying myometrium, raising concern for a Cesarean scar implantation. 

A corpus luteum is noted in the right ovary. 19 mm avascular echogenic lesion within the left ovary is in keeping with a dermoid cyst. This had been seen on prior studies.


Further obstetric history of note:

G14P7, 4xCS, 1xectopic, 3xTOP

Scan performed one week later (9w0d) confirms placental implantation as C-section scar with thinned overlying myometrium and prominent vascularity at the placental site.

The patient was referred urgently to the Fetal-Maternal Unit for further assessment and management but unfortunately did not attend, and was lost to followup until she represented in the mid-trimester 

21 weeks 6 days


Fetal anatomy normal (not shown)

Anterior placenta, inferior edge covers internal os by 32mm. Cord insertion into the placenta is centric. No definite myometrium seen in anterior lower uterine segment. Subplacental hypervascularity noted which appears to extend into anterior abdominal soft tissue. No definite bladder wall serosa seen with increased vascularity posterior to placenta.


Inferior margin covers internal os by 3.8 cm.

In the midline uterus, above the level of the lower segment, there appears to be a lack of sliding between the anterior uterine wall and peritoneum.

Findings are suggestive of placenta percreta above the level of the lower segment, in the midline (possible history of prior classical C-section). At this point there is no visible myometrium, the placenta appears to be in continuity with overlying tissues, probably peritoneum.

Complete placenta previa with the placenta predominately anterior.

There is bulging of the uterine wall is strongly suggestive of full-thickness myometrial implantation or placenta percreta.

The interface between the uterus and bladder is normal in appearance. However, abnormally prominent vessels are identified in the subcutaneous fat deep to the rectus abdominous divarication.


Within an area of increased subcutaneous fat vascularity there is a much smaller area measuring, located 5 mm superior to the Cesarean scar where there is the impression of extension of placental tissue to the linea alba.

No evidence of retroplacental hemorrhage.


Surgical feedback: Upon opening the abdominal cavity, there was a lot of omental adhesion to the anterior abdominal wall, the placenta (as pictured here) has migrated through the uterus and the bladder was attached to that but fortunately the bladder was not adherent to the lower part of the uterus and around the cervix.  There was dense omental adhesion with large vessels to the anterior wall

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