No abstract

In women with persistent placenta previa or low-lying placenta and prior cesarean delivery, the smallest anterior myometrial thickness on first-trimester sonography significantly improved detection of morbidly adherent placenta.

Likelihood of vaginal bleeding necessitating delivery declined with advancing gestation in pregnancies with placenta accreta as did blood loss. Most were delivered at 36 weeks of gestation or greater, nearly 90% in the absence of bleeding complications. Thus, although preterm delivery is an important consideration when placenta accreta is suspected, our findings support individualizing delivery planning.

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The levonorgestrel-releasing IUD is significantly less conspicuous than the copper IUD on 2D imaging. Three-dimensional ultrasound enhances the conspicuity of both types of IUD.

Objectives-To prospectively evaluate low implantation of the gestational sac and other first-trimester ultrasound (US) parameters for prediction of placenta accreta spectrum (PAS). Methods-Women with a diagnosis of low implantation on clinically indicated first-trimester US underwent a transvaginal US examination at 10 to 13 weeks' gestation to assess the trophoblast location, anechoic areas, bridging vessels, and smallest myometrial thickness (SMT). The placental location was evaluated in the second trimester, and serial US examinations were performed in cases of low placentation. Placenta accreta spectrum was based on clinical findings and confirmed by histologic results. Results-Of 68 women, 40 (59%) had prior cesarean delivery (CD). Hysterectomy was performed in 8, all with prior CD. Of these, 7 (88%) had US suspicion of PAS. In 16 with prior CD and basalis overlying the internal os, 9 (56%) had second-trimester placenta previa, and 7 of 9 (78%) underwent hysterectomy with pathologic confirmation of PAS. Of 28 without prior CD, there were no cases of persistent low placentation in the third trimester regardless of the trophoblast location. Ultrasound parameters associated with PAS were a smaller distance from the inferior trophoblastic border to the external os, disruption of the bladder-serosal interface, bridging vessels, anechoic areas, and the SMT. In women with prior CD, use of the SMT in the sagittal plane yielded an area under the receiver operating characteristic curve of 0.96 (95% confidence interval, 0.91-1.00). Conclusions-First-trimester low implantation increases the risk of persistent placenta previa and PAS in women with prior CD. All parameters were associated with PAS, the most predictive being the SMT. Key Words-cesarean scar pregnancy; first-trimester ultrasound; low implantation; placenta accreta spectrum P lacenta accreta spectrum (PAS) is a life-threatening obstetric complication occurring when the placenta abnormally adheres to or invades the myometrium. Once rare, PAS now complicates as many as 1 per 300 pregnancies in the United States, with the substantial rise in the incidence paralleling the rise in cesarean delivery (CD) rates, a known risk factor for PAS. 1-3 When compared with intrapartum diagnosis, prenatal diagnosis of PAS improves maternal outcomes by allowing for multidisciplinary planning and delivery before the onset of labor, vaginal bleeding, or both, thus reducing maternal and fetal morbidity. 2,4-7

Objectives The purpose of this study was to review first‐trimester transvaginal sonograms of patients with cervicoisthmic implantations and prior cesarean deliveries to determine whether sonographic biometric measurements can distinguish between abnormally adherent trophoblastic implantations and normally implanted pregnancies. Methods Our database was reviewed from October 2006 through December 2011 for patients with first‐trimester sonographic diagnoses of cervicoisthmic implantations and previous cesarean deliveries. Biometric measurements of the smallest distance from the anterior trophoblastic border to the uterine serosa were performed on transvaginal sagittal images of the uterus. Outcomes were classified into 5 categories: cesarean scar pregnancy, placental invasion (accreta/increta/percreta), previa without invasion, spontaneous abortion, and delivered intrauterine pregnancy. Statistical methods included analysis of variance with the Tukey range test and Student t test. Results Of 77 studies, outcome data were available for 56 patients. The mean gestational age was 8.8 weeks (minimum, 2.0 weeks; maximum, 14.9 weeks). The anterior trophoblastic border distances from the uterine serosa were significantly smaller in cesarean scar pregnancies (mean, 1.6 mm; SD, 0.6 mm) and placental invasion pregnancies (mean, 2.2 mm; SD, 1.0 mm) than the normally implanted groups (mean, 7.9 mm, SD, 3.3 mm; P < .0001). Conclusions Smaller trophoblastic border distances to the anterior uterine serosa are seen in abnormally adherent trophoblastic implantations, and these distances distinguish them from other pregnancy outcomes.

Ultrasound characteristics can be used to diagnose the classic-appearing nonneoplastic entities, benign neoplasms and malignancies. In cases in which the appearance of an ovarian mass is not classic, assignment of relative risk of malignancy using a multiparametric model is appropriate and beneficial for patient management.