Perinatal assessment of complex cesarean delivery: beyond placenta accreta spectrum

Multiple cesarean deliveries are known to be associated with long-term postoperative consequences because of a permanent defect of the lower uterine segment wall and the development of thick pelvic adhesions. Patients with a history of multiple cesarean deliveries often present with large cesarean scar defects and are at heightened risk in subsequent pregnancies of cesarean scar ectopic pregnancy, uterine rupture, low-lying placenta or placenta previa, and placenta previa accreta. Moreover, large cesarean scar defects will lead to progressive dehiscence of the lower uterine segment with the inability to effectively reapproximate hysterotomy edge and repair at birth. Major remodeling of the lower uterine segment associated with true placenta accreta spectrum at birth, whereby the placenta becomes inseparable from the uterine wall, increases the rates of perinatal morbidity and mortality, especially when undiagnosed before delivery. Ultrasound imaging is currently not routinely used to evaluate the surgical risks of patients with a history of multiple cesarean deliveries, beyond the risk assessment of placenta accreta spectrum. Independent of accreta placentation, a placenta previa under a scarred, thinned partially disrupted lower uterine segment, covered by thick adhesions with the posterior wall of the bladder, poses a surgical risk and requires fine dissection and surgical expertise; however, data on the use of ultrasound to evaluate uterine remodeling and adhesions between the uterus and other pelvic organs are scarce. In particular, transvaginal sonography has been underused, including in patients with a high probability of placenta accreta spectrum at birth. Based on the best available knowledge, we discuss the role of ultrasound imaging in identifying the signs suggestive of major remodeling of the lower uterine segment and in mapping the changes in the uterine wall and pelvis, to enable the surgical team to prepare for all different types of complex cesarean deliveries. The need for postnatal confirmation of the prenatal ultrasound findings for all patients with a history of multiple cesarean deliveries, regardless of the diagnosis of placenta previa and placenta accreta spectrum, is discussed. We propose an ultrasound imaging protocol and a classification of the level of surgical difficulty at elective cesarean delivery to stimulate further research toward the validation of ultrasound signs by which these signs may be applied to improve surgical outcomes

Validation of a sonographic checklist for the detection of histologic placenta accreta spectrum

Background: To standardize research terminology and reduce unanticipated placenta accreta spectrum (PAS), the European Working Group for Abnormally Invasive Placenta (EW-AIP) developed a consensus checklist for reporting PAS suspected on antenatal ultrasound. The diagnostic accuracy of the EW-AIP checklist has not been assessed. Objective: To test the performance of the EW-AIP sonographic checklist in predicting histologic PAS. Study Design: This is a multi-site, blinded, retrospective review of transabdominal ultrasound studies performed between 26-32 weeks gestation for subjects with histologic PAS between 2016-2020. We matched a 1:1 control cohort of subjects without histologic PAS. To reduce reader bias, we matched the control cohort for known risk factors including previa, number of prior cesarean deliveries, prior dilation and curettage (D&C), in vitro fertilization (IVF), and clinical factors affecting image quality including multiple gestation, body mass index (BMI) and gestational age at the ultrasound. Nine sonologists from 5 referral centers, blinded to the histologic outcomes, interpreted the randomized ultrasound studies using the EW-AIP checklist. The primary outcome was the sensitivity and specificity of the checklist to predict PAS. Two separate sensitivity analyses were performed: 1) we excluded subjects with mild disease (i.e. only assessed subjects with histologic increta and percreta); 2) we excluded interpretations from the 2 most junior sonologists. Results: 78 subjects were included (39 PAS, 39 matched control). Clinical risk factors and image quality markers were statistically similar between cohorts. The checklist sensitivity (95% Confidence Interval, CI) was 76.6% (63.4%-90.6%) and specificity (95% CI) was 92.0% (63.4%-99.9%), with a positive and negative likelihood ratio of 9.6 and 0.3, respectively. When we excluded subjects with mild PAS disease, the sensitivity (95% CI) increased to 84.7% (73.6%-96.4%) and specificity was unchanged at 92.0% (83.2%-99.9%). Sensitivity and specificity were unchanged when the interpretations from the 2 most junior sonologists were excluded. Conclusion: The 2016 EW-AIP checklist for interpreting PAS has a reasonable performance in detecting and excluding histologic placenta accreta spectrum

Association of multifetal gestation with obstetric and neonatal outcomes in gestational carrier pregnancies.

OBJECTIVE: Multifetal gestation is more frequent among gestational carrier pregnancies than non-surrogacy IVF pregnancies. We aimed to evaluate the association between multifetal gestation and obstetric and neonatal morbidity among gestational carrier pregnancies. METHODS: Pooled cross-sectional study of birth certificate data from gestational carrier pregnancies in Utah from 2009 to 2018. Our primary outcome was a composite of severe obstetric morbidity; secondary outcomes included cesarean delivery (CD), hypertensive disorders of pregnancy, preterm birth (PTB), and a neonatal morbidity composite. Logistic regression was utilized to compare odds of these outcomes between gestational carrier pregnancies with and without multifetal gestation. RESULTS: A total of 361 gestational carrier pregnancies resulted in the delivery of 435 neonates during the study period. Of these, 284 were singleton pregnancies, and 77 were multifetal, a multifetal gestation rate of 21.3%. Baseline demographic characteristics did not differ between singleton and multifetal gestations. Multifetal gestation was not associated with higher rates of severe obstetric morbidity (odds ratio [OR] 1.87, 95% confidence interval [CI] 0.34-10.39). Multifetal gestation was associated with increased odds of neonatal morbidity (OR 9.49, 95% CI 5.35-15.83); PTB < 37, 34, and 32 weeks (OR 21.88, 95% CI 11.64-41.12; OR 11.67, 95% CI 5.25-25.91; OR 8.79, 95% CI 3.41-22.68); and CD (OR 4.82, 95% CI 2.81-8.27). CONCLUSION: Severe obstetric morbidity did not differ between singleton and multifetal gestations among gestational carrier pregnancies. However, multifetal gestation was associated with increased odds of neonatal morbidity, CD, and PTB. This information may be useful when counseling prospective gestational carriers and intended parents

Pitfalls in sonographic evaluation of placenta accreta spectrum

Placenta accreta spectrum (PAS) is a serious complication of pregnancy. Preoperative diagnosis improves outcome for both mother and infant therefore it is critical that obstetric imagers are aware of the signs of the disease and know how to avoid pitfalls in diagnosis. This article reviews and illustrates the sonographic signs that are most helpful in detection of PAS and provides tips on avoiding pitfalls in diagnosis

Obstetric morbidity in gestational carrier pregnancies: a population-based study

PurposeWe sought to characterize severe obstetric morbidity among women who are gestational carriers compared to other patients.MethodsThis was a population-based study comparing gestational carrier pregnancies to non-surrogate pregnancies (non-surrogate IVF pregnancies, all non-gestational carrier pregnancies, and a cohort of matched controls) delivering in Utah between 2009 and 2018, using birth certificate data. Our primary outcome was a composite of severe morbidity, including death, ICU admission, eclampsia, HELLP syndrome, transfusion, and unplanned hysterectomy. Our secondary outcomes were cesarean delivery (CD) and hypertensive disorders of pregnancy.ResultsDuring the study period, 361 gestational carrier pregnancies and 509,015 other pregnancies resulted in live births. Severe morbidity was less common among gestational carrier pregnancies than IVF pregnancies (1.7% versus 5.5%, odds ratio [OR] 0.29, 95% confidence interval [CI] 0.12-0.70), but was not different when compared to all other pregnancies (1.0%, OR 1.61, 95% CI 0.72-3.60), or a cohort of matched controls (1.0%, OR 1.37, 95% CI 0.55-3.40). CD was less common among gestational carrier pregnancies than IVF pregnancies, but not different than all other pregnancies or matched controls. While frequency of hypertensive disorders of pregnancy was lower among gestational carrier pregnancies than IVF pregnancies, it was higher than all other women who delivered and comparable to matched controls.ConclusionSevere obstetric morbidity is uncommon among gestational carrier pregnancies. Women who are gestational carriers are at lower risk of morbidity and CD than others who conceive through IVF and do not appear to be at increased risk compared to matched controls