Natural history of early first-trimester pregnancies implanted in Cesarean scars.

To describe the ultrasound findings and natural history of pregnancies implanted within or on Cesarean section scars in the first trimester of pregnancy. This was a prospective observational study of 10 women diagnosed with a pregnancy implanted in or on a Cesarean section scar in the first trimester, who declined medical intervention because of their desire to continue the pregnancy. The study population comprised women at < 12 weeks' gestation who were seen in our early pregnancy unit between January 2011 and September 2013. Nine women were followed up by serial ultrasound examinations and had detailed care plans for delivery at King's College Hospital (KCH). One woman was followed up and delivered at another teaching hospital. The first-trimester ultrasound findings were compared with the clinical outcome of the pregnancy. The nine patients who were followed up at KCH developed ultrasound findings of morbidly adherent placenta (MAP) in the second and third trimesters. All 10 patients were diagnosed with MAP at the time of delivery by Cesarean section. The gestational age at delivery ranged from 26 to 38 weeks. The uterus was conserved in five patients, and Cesarean hysterectomy was performed in the remaining five. All three women with complete implantation of the gestational sac within the scar and two of three cases with placental lakes in the first trimester had hysterectomies. The two cases with bulging of the gestational sac out of the uterine contour had a preterm emergency hysterectomy due to placenta percreta. Histology confirmed placenta accreta in the five hysterectomy specimens. There were no fetal or neonatal complications. Implantation of a pregnancy on or in a Cesarean section scar is a precursor of MAP; however, the degree of morbidity associated with this implantation is variable and difficult to predict based on first-trimester ultrasound findings only. The assessment of ongoing pregnancies implanted in Cesarean scars is most beneficial when performed between 7 and 9 weeks' gestation. Complete implantation within the myometrial defect, bulging of the trophoblast from the uterine contour and large placental lakes in the first trimester are ultrasound findings that may predict severe placenta accreta or percreta and consequently a poor outcome.

Zosmer N ，Fuller J ，Shaikh H ，Johns J ，Ross JA ... -  《-》

The clinical outcome of cesarean scar pregnancies implanted "on the scar" versus "in the niche".

The term cesarean scar pregnancy refers to placental implantation within the scar of a previous cesarean delivery. The rising numbers of cesarean deliveries in the last decades have led to an increased incidence of cesarean scar pregnancy. Complications of cesarean scar pregnancy include morbidly adherent placenta, uterine rupture, severe hemorrhage, and preterm labor. It is suspected that cesarean scar pregnancies that are implanted within a dehiscent scar ("niche") behave differently compared with those implanted on top of a well-healed scar. To date there are no studies that have compared pregnancy outcomes between cesarean scar pregnancies implanted either "on the scar" or "in the niche." The purpose of this study was to determine the pregnancy outcome of cesarean scar pregnancy implanted either "on the scar" or "in the niche." This was a retrospective 2-center study of 17 patients with cesarean scar pregnancy that was diagnosed from 5-9 weeks gestation (median, 8 weeks). All cesarean scar pregnancies were categorized as either implanted or "on the scar" (group A) or "in the niche" (group B), based on their first-trimester transvaginal ultrasound examination. Clinical outcomes based on gestational age at delivery, mode of delivery, blood loss at delivery, neonate weight and placental histopathologic condition were compared between the groups with the use of the Mann-Whitney U test. Myometrial thickness overlying the placenta was compared among all the patients who required hysterectomy and those who did not with the use of the Mann-Whitney U test. Myometrial thickness was also correlated with gestational age at delivery with the use of Spearman's correlation. Group A consisted of 6 patients; group B consisted of 11 patients. Gestational age at delivery was lower in group B (median, 34 weeks; range, 20-36 weeks) than in group A (median, 38 weeks; range, 37-39 weeks; P=.001). In group A, 5 patients were delivered via cesarean delivery (with normal placenta), and 1 patient underwent a cesarean-hysterectomy for placenta accreta. In group B, 10 patients had a cesarean-hysterectomy for placenta increta/percreta, and 1 patient underwent gravid-hysterectomy for vaginal bleeding at 20 weeks gestation. Blood loss was increased, but not significantly higher in group B (median, 1200 mL; range, 600-4000 mL) than in group A (median, 700 mL; range, 600-1400 mL; P=.117). Myometrium was statistically significantly thinner in the patients group that require hysterectomy (median, 1 mm; range, 0-2 mm) than in the group that did not (median, 5 mm; range, 4-9 mm; P=.001). Myometrial thickness showed a positive correlation with the gestational age (r=0.820; P<.0005). Patients with cesarean scar pregnancy implanted "on the scar" had a substantially better outcome compared with patients in whom the cesarean scar pregnancy implanted "in the niche." Myometrial thickness <2 mm in the first-trimester ultrasound examination is associated with morbidly adherent placenta at delivery.

Kaelin Agten A ，Cali G ，Monteagudo A ，Oviedo J ，Ramos J ，Timor-Tritsch I ... -  《-》

Development of the utero-placental circulation in cesarean scar pregnancies: a case-control study.

Cesarean scar pregnancies carry a high risk of pregnancy complications including placenta previa with antepartum hemorrhage, placenta accreta spectrum, and uterine rupture. To evaluate the development of utero-placental circulation in the first half of pregnancy in ongoing cesarean scar pregnancies and compare it with pregnancies implanted in the lower uterine segment above a previous cesarean delivery scar with no evidence of placenta accreta spectrum at delivery STUDY DESIGN: This was a retrospective case-control study conducted in 2 tertiary referral centers. The study group included 27 women who were diagnosed with a live cesarean scar pregnancy in the first trimester of pregnancy and who elected to conservative management. The control group included 27 women diagnosed with an anterior low-lying placenta or placenta previa at 19 to 22 weeks of gestation who had first and early second trimester ultrasound examinations. In both groups, the first ultrasound examination was carried out at 6 to 10 weeks to establish the pregnancy location, viability, and to confirm the gestational age. The utero-placental and intraplacental vasculatures were examined using color Doppler imaging and were described semiquantitatively using a score of 1 to 4. The remaining myometrial thickness was recorded in the study group, whereas the ultrasound features of a previous cesarean delivery scar including the presence of a niche were noted in the controls. Both the cesarean scar pregnancies and the controls had ultrasound examinations at 11 to 14 and 19 to 22 weeks of gestation. The mean color Doppler imaging vascularity score in the ultrasound examination at 6 to 10 weeks was significantly (P<.001) higher in the cesarean scar pregnancy group than in the controls. High vascularity scores of 3 and 4 were recorded in 20 of 27 (74%) cases of the cesarean scar pregnancy group. There was no vascularity score of 4, and only 3 of 27 (11%) controls had a vascularity score of 3. In 15 of the 27 (55.6%) cesarean scar pregnancies, the residual myometrial thickness was <2 mm. In the ultrasound examination at 11 to 14 weeks, there was no significant difference between the groups in the number of cases with an increased subplacental vascularity. However, 12 cesarean scar pregnancies (44%) presented with 1 or more placental lacunae whereas there was no case with lacunae in the controls. Of the 18 cesarean scar pregnancies that progressed into the third trimester, 10 of them were diagnosed with placenta previa accreta at birth, including 4 creta and 6 increta. In the 19 to 22 weeks ultrasound examination, 8 of the 10 placenta accreta spectrum patients presented with subplacental hypervascularity, out of which 6 showed placental lacunae. The vascular changes in the utero-placental and intervillous circulations in cesarean scar pregnancies are due to the loss of the normal uterine structure in the scar area and the development of placental tissue in proximity of large diameter arteries of the outer uterine wall. The intensity of these vascular changes, the development of placenta accreta spectrum, and the risk of uterine rupture are probably related to the residual myometrial thickness of the scar defect at the start of pregnancy. A better understanding of the pathophysiology of the utero-placental vascular changes associated with cesarean scar pregnancies should help in identifying those cases that may develop major complications. It will contribute to providing counseling for women about the risks associated with different management strategies.

Jauniaux E ，Zosmer N ，De Braud LV ，Ashoor G ，Ross J ，Jurkovic D ... -  《-》

Natural history of Cesarean scar pregnancy on prenatal ultrasound: the crossover sign.

Advances in prenatal imaging techniques have led to an increase in the diagnosis of Cesarean scar pregnancy (CSP). However, antenatal counseling when CSP is diagnosed is challenging, and current evidence is derived mainly from small series reporting high rates of adverse maternal outcomes. The aim of this study was to ascertain the performance of prenatal ultrasound in predicting the natural history of CSP using a new sonographic sign, the crossover sign (COS). This was a retrospective analysis of early first-trimester (6-8 weeks' gestation) ultrasound images in women with morbidly adherent placenta (MAP) managed in the third trimester of pregnancy. The relationship between the gestational sac of the CSP, anterior uterine wall and Cesarean scar, defined as the COS, was analyzed to determine whether it could predict evolution in these cases. Odds ratios (ORs) were calculated and logistic regression analysis was performed to investigate the association between different types of COS (COS-1, COS-2+ or COS-2-) and the occurrence of MAP. Sixty-eight pregnancies with MAP were included. The risk of placenta percreta was significantly higher in pregnancies with COS-1 than in those with COS-2 (OR, 6.67 (95% CI, 1.3-33.3)). When evaluating the two variants of COS-2 separately, the risk of placenta percreta was significantly higher in pregnancies with COS-1 vs COS-2+ (OR, 5.83 (95% CI, 1.1-30.2)) and this risk was even higher when comparing cases with COS-1 vs COS-2- (OR, 12.0 (95% CI, 1.9-75.7)). Logistic regression analysis showed that COS-1 was associated independently with severe forms of MAP, such as placenta percreta and increta (OR, 12.85 (95% CI, 2.0-84.0)), while COS-2+ was associated independently with placenta accreta (OR, 4.37 (95% CI, 1.1-17.0)). Ultrasound assessment of the relationship between the gestational sac of a CSP and the endometrial line (the COS) may help to determine whether a CSP will progress towards a less severe form of MAP, amenable to postnatal treatment, and successful pregnancy outcome. Large prospective studies are needed to confirm our findings and elucidate the natural history of this condition. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Cali G ，Forlani F ，Timor-Tritsch IE ，Palacios-Jaraquemada J ，Minneci G ，D'Antonio F ... -  《-》

Value of first-trimester ultrasound in prediction of third-trimester sonographic stage of placenta accreta spectrum disorder and surgical outcome.

To explore whether early first-trimester ultrasound can predict the third-trimester sonographic stage of placenta accreta spectrum (PAS) disorder and to elucidate whether combining first-trimester ultrasound findings with the sonographic stage of PAS disorder can stratify the risk of adverse surgical outcome in women at risk for PAS disorder. This was a retrospective analysis of prospectively collected data from women with placenta previa, and at least one previous Cesarean delivery (CD) or uterine surgery, for whom early first-trimester (5-7 weeks' gestation) ultrasound images could be retrieved. The relationship between the position of the gestational sac and the prior CD scar was assessed using three sonographic markers for first-trimester assessment of Cesarean scar (CS) pregnancy, reported by Calí et al. (crossover sign (COS)), Kaelin Agten et al. (implantation of the gestational sac on the scar vs in the niche of the CS) and Timor-Tritsch et al. (position of the center of the gestational sac below vs above the midline of the uterus), by two different examiners blinded to the final diagnosis and clinical outcome. The primary aim of the study was to explore the association between first-trimester ultrasound findings and the stage of PAS disorder on third-trimester ultrasound. Our secondary aim was to elucidate whether the combination of first-trimester ultrasound findings and sonographic stage of PAS disorder can predict surgical outcome. Logistic regression analysis and area under the receiver-operating-characteristics curve (AUC) were used to analyze the data. One hundred and eighty-seven women with vasa previa were included. In this cohort, 79.6% (95% CI, 67.1-88.2%) of women classified as COS-1, 94.4% (95% CI, 84.9-98.1%) of those with gestational-sac implantation in the niche of the prior CS and 100% (95% CI, 93.4-100%) of those with gestational sac located below the uterine midline, on first-trimester ultrasound, were affected by the severest form of PAS disorder (PAS3) on third-trimester ultrasound. On multivariate logistic regression analysis, COS-1 (odds ratio (OR), 7.9 (95% CI, 4.0-15.5); P < 0.001), implantation of the gestational sac in the niche (OR, 29.1 (95% CI, 8.1-104); P < 0.001) and location of the gestational sac below the midline of the uterus (OR, 38.1 (95% CI, 12.0-121); P < 0.001) were associated independently with PAS3, whereas parity (P = 0.4) and the number of prior CDs (P = 0.5) were not. When translating these figures into diagnostic models, first-trimester diagnosis of COS-1 (AUC, 0.94 (95% CI, 0.91-0.97)), pregnancy implantation in the niche (AUC, 0.92 (95% CI, 0.89-0.96)) and gestational sac below the uterine midline (AUC, 0.92 (95% CI, 0.88-0.96)) had a high predictive accuracy for PAS3. There was an adverse surgical outcome in 22/187 pregnancies and it was more common in women with, compared to those without, COS-1 (P < 0.001), gestational-sac implantation in the niche (P < 0.001) and gestational-sac position below the uterine midline (P < 0.001). On multivariate logistic regression analysis, third-trimester ultrasound diagnosis of PAS3 (OR, 4.3 (95% CI, 2.1-17.3)) and first-trimester diagnosis of COS-1 (OR, 7.9 (95% CI, 4.0-15.5); P < 0.001), pregnancy implantation in the niche (OR, 29.1 (95% CI, 8.1-79.0); P < 0.001) and position of the sac below the uterine midline (OR, 6.6 (95% CI, 3.9-16.2); P < 0.001) were associated independently with adverse surgical outcome. When combining the sonographic coordinates of the three first-trimester imaging markers, we identified an area we call high-risk-for-PAS triangle, which may enable an easy visual perception and application of the three methods to prognosticate the risk for CS pregnancy and PAS disorder, although it requires validation in large prospective studies. Early first-trimester sonographic assessment of pregnancies with previous CD can predict reliably ultrasound stage of PAS disorder. Combination of findings on first-trimester ultrasound with second- and third-trimester ultrasound examination can stratify the surgical risk in women affected by a PAS disorder. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Calí G ，Timor-Tritsch IE ，Forlani F ，Palacios-Jaraquemada J ，Monteagudo A ，Kaelin Agten A ，Flacco ME ，Khalil A ，Buca D ，Manzoli L ，Liberati M ，D'Antonio F ... -  《-》