Lacunar-like changes of the chorion: can it be a first-trimester ultrasound sign in predicting worse clinical outcome in cesarean scar pregnancy termination?

Figures & data

Figure 1. Thirty-two-year-old patient, G2P1, 62 days gestation, no lower abdominal pain or vaginal bleeding. Blood β-HCG 114,384 IU/ml. Ultrasound examination showed an elongated gestational sac of which the lower extremity located at the cesarean section scar (anterior lower segment) with scattered anechoic foci within chorion.

Figure 2. Thirty-seven-year-old patient, G3P1, 52 days gestation. She had suffered from vaginal bleeding for 12 days without lower abdominal pain. Blood β-HCG level 77,198 IU/ml. Ultrasound showed a gestational sac totally located in the lower segment cavity and protruded from uterus contour. Calipers located at the outer edge of gestational sac. CX: cervix; F: uterine cavity fluid.

Figure 3. Thirty-nine-year-old patient, G4P1, 75 days gestation. She complained vaginal bleeding for a few days. Blood β-HCG 230 IU/ml. Ultrasound detected a thickened wall gestational mass within lower uterine segment. Multiple anechoic foci of various sizes with hypo-echoic dots could be seen within the thickened wall. The double-head arrow pointed out the thickness measurement of chorion.

Figure 4. Thirty-six-year-old patient, G4P1, 50 days gestation, vaginal bleeding (+). Blood β-HCG 168,136 IU/ml. Ultrasound showed an elongated gestational sac with lower extremity implanted in the uterine lower segment (between calipers). There was no lacunar-like change of chorion membrane.

Figure 5. Measurement of minimum thickness of uterine lower segment myometrium: the hypoechoic myometrial layer (double-headed arrow) between the outer edge of the chorion (lower dotted line) and the inner edge of the uterine serosa (upper dotted line) was taken for measurement.

Figure 6. Grading of the blood signal on color Doppler flow imaging (CDFI) of uterine lower segment: (a) CDFI grade 1, very little blood signal; (b) CDFI grade 2, moderate blood signal; (c) CDFI grade 3, rich blood signal (from the same patient of Figure 3).

Table 1. Comparison of clinical manifestations and laboratory test of cesarean scar pregnancy (CSP) patients in early pregnancy.

Parameters^a	Case group^b	Control group^b	p Value
Age (years)	34.2 ± 3.9	33.6 ± 4.5	.620
Gravid number	4 (3, 4.75)	4 (3, 4)	.826
Parity number	1 (1, 2)	1 (1, 1)	.112
Cesarean section number	1 (1, 2)	1 (1, 1)	.112
Number of uterine cavity surgery^c	2.5 (2, 3.25)	2.5 (2, 3)	.526
Gestation (days)	56 (46.25, 72.75)	50 (43, 57)	.066
Lower abdominal pain (+)	8 (40)	19 (54.3)	.308
Vaginal bleeding (+)	12 (60)	21 (60)	1.000
Blood β-HCG (IU/ml)	54948.5 (10414.75, 108635.875)	49,496 (21,419, 100,751)	.740
Blood β-HCG′ (IU/ml)^d	84,907 (33,155, 178008.5)	99,586 (37,291, 112,941)	.970

^a Data are presented as the mean ± SD, median number (25% and 75% quartiles) or n (%).

^b Case group: CSP with chorionic lacunar-like changes; control group: CSP without chorionic lacunar-like changes.

^c Number of uterine cavity surgery included suction evacuation, dilation and curettage and cesarean section.

^d Blood β-HCG′: β-HCG of cases with fetal heart beat (+).

Table 2. Comparison of sonographic features of cesarean scar pregnancy (CSP) patients in early gestation.

Parameters^a	Case group^b	Control group^b	p Value
The maximum outer diameter of the gestational sac (cm)*	5.6 ± 2.5	3.9 ± 1.5	.002
The maximum thickness of the chorion (cm)*	1.05 (0.73, 1.88)	0.70 (0.50, 1.00)	.001
The minimum thickness of the myometrium at uterine lower anterior wall (cm)*	0.08 (0.00, 0.16)	0.20 (0.13, 0.26)	.001
The longitudinal diameter of implanting part of gestational mass in the uterine lower segment (cm)*	3.3 ± 1.8	1.2 ± 0.5	.000
The serosa protrusion of the uterine lower segment (%)*	12 (60)	2 (5.71)	.000
Detection of the embryo/fetus (%)	13 (65)	23 (65.7)	.957
Fetal heart beat (%)	13 (65)	19 (54.3)	.438
The crown-rump length of embryo/fetus*	1.70 (0.55, 2.05)	0.70 (0.40, 1.00)	.040
CDFI grading of lower uterine segment (%)^c,*	0, 12 (66.7), 6 (33.3)	6 (17.6), 27 (79.4), 1 (2.9)	.000
PSV (cm/s)	65.8 ± 45.8	36.2 ± 23.1	.067
RI	0.39 ± 0.11	0.47 ± 0.12	.076

* The difference is significant.

^a Data are presented as (mean ± SD), median number (25% and 75% quartiles) or n (%).

^b Case group: CSP with chorionic lacunar-like changes; control group: CSP without chorionic lacunar-like changes.

^c The level of blood signal on color Doppler flow imaging (CDFI) of lower uterine segment was divided into three grades: CDFI grade 1, very little blood signal; CDFI grade 2, moderate blood signal; CDFI grade 3, rich blood signal.

Table 3. Comparison of treatment methods and hospitalization of cesarean scar pregnancy (CSP) patients in early gestation termination.

Parameters^a	Case group^b	Control group^b	p Value
One-way treatment^c	13 (65)	28 (80)	.219
Combination treatment^c	7 (35)	7 (20)
Treatment including lesion resection in surgery or laparoscopy*	7 (35)	1 (2.86)	.002
Combination of UAE^d	14 (70)	24 (68.6)	.912
Surgical bleeding*	35 (20, 200)	20 (20, 22.5)	.036
Total hospitalization days*	7.5 (4, 11.75)	3.5 (2, 6.25)	.006
Hospitalization more than twice	3 (15.0)	5 (14.3)	1.000

* The difference is significant.

^a Data are presented as median number (25% and 75% quartiles) or n (%).

^b Case group: CSP with chorionic lacunar-like changes; control group: CSP without chorionic lacunar-like changes.

^c Treatment modality of CSP including suction and curettage under ultrasound guidance or laparoscopic surveillance, scar pregnancy lesion resection under laparoscopy or open surgery and methotrexate (MTX) chemotherapy through muscle injection. UAE usage which was an assistant way to control bleeding was not included in the above treatment.

^d UAE: uterine artery thrombosis.