Mammalian target of rapamycin inhibitors: A new-possible approach for in-utero medication therapy.

The mammalian/mechanistic target of rapamycin (mTOR) is a protein kinase that plays a crucial role in regulating cellular growth, metabolism, and survival. Although there is no absolute contraindication for the use of mTOR inhibitors during pregnancy, the specific fetal effects remain unknown. Available data from the past 2 decades have examined the use of mTOR inhibitors during pregnancy in patients with solid organ transplantation, showing no clear link to fetal complications or structural abnormalities. Recently, a handful of case reports and series have described transplacental therapy of mTOR inhibitors to control symptomatic and complicated pathologies in the fetus. The effect of these agents includes a significant reduction in lesion size in the fetus and a reduced need for mechanical ventilation in neonates. In this context, we delve into the potential of mTOR inhibitors as in-utero therapy for fetal abnormalities, with a primary focus on lymphatic malformation (LM) and cardiac rhabdomyoma (CR). While preliminary reports underscore the efficacy of mTOR inhibitors for the treatment of fetal CR and fetal brain lesions associated with tuberous sclerosis complex, chylothorax, and LMs, additional investigation and clinical trials are essential to comprehensively assess the safety and efficacy of these medications.

Abnormal Shape and Size of the Cardiac Ventricles Are Associated with a Higher Risk of Neonatal Death in Fetuses with Isolated Left Congenital Diaphragmatic Hernia.

INTRODUCTION: The objective of this study was to evaluate the association between fetal cardiac deformation analysis (CDA) and cardiac function with severe adverse perinatal outcomes in fetuses with isolated left congenital diaphragmatic hernia (CDH). METHODS: CDA in each ventricle (contractility, size, and shape), evaluated by speckle tracking and novel FetalHQ software, and markers of cardiac function (E/A ratios, pulmonary and aortic peak systolic velocities, and sigmoid annular valve diameters), were evaluated in fetuses with isolated left CDH. Two evaluations were performed: at referral (CDA and function) and within 3 weeks of delivery (CDA). Severe adverse neonatal outcomes were considered neonatal death (ND) or survival with CDH-associated pulmonary hypertension (CDH-PH). Differences and associations between CDA, cardiac function, and severe adverse outcomes were estimated. RESULTS: Fifty fetuses were included, and seventeen (34%) had severe adverse neonatal outcomes (11 ND and 6 survivors with CDH-PH). At first evaluation, the prevalence of a small left ventricle was 34% (17/50) with a higher prevalence among neonates presenting severe adverse outcomes (58.8 [10/17] vs. 21.2% [7/33]; p = 0.01; OR, 5.03 [1.4-19.1; p = 0.01]) and among those presenting with neonatal mortality (8/11 [72.7] vs. 9/39 [23.0%]; p = 0.03; OR, 8.9 [1.9-40.7; p = 0.005]). No differences in cardiac function or strain were noted between fetuses with or without severe adverse outcomes. Within 3 weeks of delivery, the prevalence of small left ventricle was higher (19/34; 55.8%) with a more globular shape (reduced transverse/longitudinal ratio). A globular right ventricle was significantly associated with ND or survival with CDH-PH (OR, 14.2 [1.5-138.3]; p = 0.02). CONCLUSION: Fetuses with isolated CDH at risk of perinatal death or survival with CDH-PH had a higher prevalence of a small left ventricle and abnormal shape of the right ventricle.

Morphometric Analysis of Spina Bifida after Fetal Repair Shows New Subtypes with Associated Outcomes.

Importance: The binary classification of spina bifida lesions as myelomeningocele (with sac) or myeloschisis (without sac) belies a spectrum of morphologies, which have not been correlated to clinical characteristics and outcomes. Objective: To characterize spina bifida lesion types and correlate them with preoperative presentation and postoperative outcomes. Design: Secondary analysis of images and videos obtained during fetoscopic spina bifida repair surgery from 2020-2023. Setting: Fetal surgery was performed at a quaternary care center. Participants: A prospective cohort of patients referred for fetal spina bifida underwent fetoscopic repair under an FDA-approved protocol. Of 60 lesions repaired, 57 had available images and were included in the analysis. Interventions or Exposures: We evaluated lesion morphology on high-resolution intraoperative images and videos to categorize lesions based on placode exposure and nerve root stretching. Main Outcomes and Measures: The reproducibility of the lesion classification was assessed via Kappa interrater agreement. Preoperative characteristics analyzed include ventricle size, tonsillar herniation level, lower extremities movement, and lesion dimensions. Outcomes included surgical time, need for patch for skin closure, gestational age at delivery, preterm premature rupture of membranes (PPROM), and neonatal cerebrospinal fluid (CSF) diversion. Results: We distinguished five lesion types that differ across a range of sac sizes, nerve root stretching, and placode exposure, with 93% agreement between examiners (p<0.001). Fetal characteristics at preoperative evaluation differed significantly by lesion type, including lesion volume (p<0.001), largest ventricle size (p=0.008), tonsillar herniation (p=0.005), and head circumference (p=0.03). Lesion level, talipes, and lower extremities movement did not differ by type. Surgical and perinatal outcomes differed by lesion type, including need for patch skin closure (p<0.001), gestational age at delivery (p=0.01), and NICU length of stay (p<0.001). PPROM, CSF leakage at birth, and CSF diversion in the NICU did not differ between lesion groups. Linear regression associated severity of ventriculomegaly with lesion type, but not with tonsillar herniation level. Conclusions and Relevance: There is a distinct phenotypic spectrum in open spina bifida with differential baseline presentation and outcomes. Severity of ventriculomegaly is associated with lesion type, rather than tonsillar herniation level. Our findings expand the classification of spina bifida to reveal a spectrum that warrants further study.

Quantifying Placenta Accreta Spectrum Severity and its associated Blood Loss: A Novel Transvaginal Ultrasound Scoring System.

BACKGROUND: Hemorrhage associated with placenta accreta spectrum (PAS) is a leading cause of maternal morbidity and mortality. Estimating blood loss in these individuals is a critical component of comprehensive preoperative planning. OBJECTIVE: A semi-quantitative score based on transvaginal ultrasound was developed and tested to predict PAS, estimate its severity, and blood loss in individuals with clinical and ultrasound evidence suggesting PAS. STUDY DESIGN: A secondary analysis was conducted of prospectively collected data from a quaternary center of patients with suspected accreta on 2D ultrasound and clinical suspicion. A pre-determined scoring system was applied based on three components: 1) uterine wall (score 0: no loss of hypo-translucent uterine wall with overlying placenta in the lower uterine segment; 1: loss of hypo-translucent <3-cm defect; 2: 3-6-cm defect; and 3: >6-cm defect); 2) arterial vascularity at the uterine wall defect (score 0: no vessels observed; 1: 1-2 vessels over the defect; 2: 3-5 vessels; and 3: >5 vessels) and 3) cervical involvement (score 0: normal cervical length without previa; 1: previa with normal cervical length; 2: short cervix with previa, minimal vascularity and small lacunae; 3: short cervix with previa, increased vascularity and large lacunae). Each patient's three domain scores determined a cumulative, final score of 0-9. Patients were managed at the discretion of a multi-disciplinary team and patient's preference among the following options: cesarean delivery with placenta removal, cesarean delivery with placenta in-situ (conservative) with or without delayed hysterectomy, or cesarean hysterectomy. The frequency of different degrees of placental invasion per pathology examination per score unit was registered. Multiple linear regression analysis was performed for association of blood loss according to score adjusted by risk factors for PAS. RESULTS: A total of 73 patients were evaluated. All 11 patients who had a score of 0 had cesarean delivery with placenta removal without evidence of intraoperative PAS, thus resulting in a 100% negative predictive value. The remaining 62 had scores between 1-9. Among patients with scores 0-3 (n=20), only one had intraoperative PAS, yielding a negative predictive value of 97%. Higher scores were associated with severe PAS forms (r=0.301, p=0.02). Based on the associations between PAS scores, clinical correlation, and blood loss, we divided patients into four categories: Category 0: PAS score 0; Category 1: scores 1-3; Category 2: scores 4-6; and Category 3: scores 7-9. The median blood loss in Category 0 = 635 ± 352 mL, Category 1 = 634 ± 599 mL, Category 2 = 1549 ± 1284 mL, and Category 3 = 1895 ± 2106 mL (p <0.001). On multivariable analysis, Category 2 (ß = 0.97, p <0.01) and Category 3 (ß = 1.26, p <0.003) were associated with significantly greater blood loss than Category 0, irrespective of type of surgery. CONCLUSION: The transvaginal ultrasound score separates groups at low risk (Category 0) and at higher risk of PAS (Categories 1-3). Categories 1-3 may provide important clinical information to estimate the risk of severe forms of PAS and of blood loss during surgery.