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Randomized controlled trials of surgery are fundamentally different from randomized controlled trials of medications because it is difficult to blind or mask a surgical procedure or perform “sham” operations. An additional challenge is the variation in skills and surgical proficiency of participating centers and surgeons. Addressing heterogeneity in surgical proficiency remains of paramount importance, especially when randomized controlled trials involve a new or complex procedure such as minimally invasive radical surgery. In the presence of such heterogeneity, it is very cumbersome to evaluate objectively and monitor surgical skills so that most trials simply report associations that are averaged across surgeons and hospitals/centers. Such reporting is not transparent because the rates of complications and adverse outcomes are reported only as averages, and these averages may not apply to the individual participating surgeons or centers. These factors, coupled with the inherent nongeneralizability of findings from such randomized controlled trials, because of the strict inclusion and exclusion criteria for enrollment, may lead to conclusions that no longer apply to real life for individual surgeons or centers. Case in point is a recently published noninferiority randomized controlled trial that reported that minimally invasive radical hysterectomy was associated with lower rates of disease-free survival (86% vs 96.5% at 4.5 years) and overall survival (93.8% vs 99% at 3 years) than open abdominal radical hysterectomy in patients with cervical cancer. However, randomized controlled trials that involve 2 competing complex or new procedures may be affected by tremendous confounding because of variations in surgical proficiency and also nonstandardization for other confounding factors such as patient selection categories (ie, stage of cancer) and adjuvant postoperative therapies that may affect long-term survival. The purpose of this Viewpoint is not to provide an exhaustive review of the trial's shortcomings but to use it as an illustration to focus on 2 challenging areas that most randomized controlled trials of a new complex surgical procedure suffer from: (1) unadjusting or not correcting for surgical skill variability and (2) nontransparent reporting of averaged results. We provide suggestions to overcome these deficiencies through robust methods and statistical approaches.

Background There is a paucity of data describing the effects of coronavirus disease 2019 on placental pathology, especially in asymptomatic patients. Although the pathophysiology of coronavirus disease 2019 is not completely understood, there is emerging evidence that it causes a severe systemic inflammatory response and results in a hypercoagulable state with widespread microthrombi. We hypothesized that it is plausible that a similar disease process may occur in the fetal-maternal unit. Objective This study aimed to determine whether coronavirus disease 2019 in term patients admitted to labor and delivery, including women without coronavirus disease 2019 symptomatology, is associated with increased placental injury compared with a cohort of coronavirus disease 2019–negative controls. Study Design This was a retrospective cohort study performed at NYU Winthrop Hospital between March 31, 2020, and June 17, 2020. During the study period, all women admitted to labor and delivery were routinely tested for severe acute respiratory syndrome coronavirus 2 regardless of symptomatology. The placental histopathologic findings of patients with coronavirus disease 2019 (n=77) who delivered a singleton gestation at term were compared with a control group of term patients without coronavirus disease 2019 (n=56). Controls were excluded if they had obstetrical or medical complications including fetal growth restriction, oligohydramnios, hypertension, diabetes, coagulopathy, or thrombophilia. Multivariable logistic regression models were performed for variables that were significant (P Results In univariable analyses, coronavirus disease 2019 cases were more likely to have evidence of fetal vascular malperfusion, that is, presence of avascular villi and mural fibrin deposition (32.5% [25/77] vs 3.6% [2/56], P Conclusion Despite the fact that all neonates born to mothers with coronavirus disease 2019 were negative for severe acute respiratory syndrome coronavirus 2 by polymerase chain reaction, we found that coronavirus disease 2019 in term patients admitted to labor and delivery is associated with increased rates of placental histopathologic abnormalities, particularly fetal vascular malperfusion and villitis of unknown etiology. These findings seem to occur even among asymptomatic term patients.

Placental implantation abnormalities (PIAs) comprise a large group of disorders associated with significant maternal, fetal, and neonatal morbidity.Risk factors include prior uterine surgery/myometrial scarring and the presence of placenta previa with or without prior cesarean delivery. Newly identified risk factors include previous prelabor cesarean delivery and previous postpartum hemorrhage. PIAs contribute substantially to preterm birth with prematurity rates ranging from 38 to 82%. Diagnosis is typically made by ultrasound in the second or third trimester; transvaginal ultrasound and color Doppler are useful in evaluating for placental invasion, placental edge thickness, presence of fetal vessels, and cervical length. Suggestive MRI features include increased vascularity, dark T2 bands, uterine bulging, thin or indistinct myometrium, and loss of dark T2 interface. An important first-trimester finding is the implantation of the gestational sac into prior hysterotomy scar (cesarean scar pregnancy). Recommendations for delivery are universally preterm and based on expert opinion. Proposed management strategies are outlined depending on cervical length, distance between internal cervical os and placenta, and placental edge thickness.There has been a recent shift in focus to individualizing management in order to improve delivery timing and in some cases even decrease risks associated with prematurity. There is a need for larger prospective studies or randomized trials to show that individualizing care can improve outcomes.