Research highlights

NAFTNet supports several research projects in the field of fetal medine. Below are studies that are currently active. To obtain more information regarding these research projects, or to contact the principal investigator, you need to register to this site.
NAFTNet endorses these projects, but the conduct of the research is the responsibility of the individual investigators.



Click here to access the list of publications about NAFTNet and scientific publications about research performed under the auspices of NAFTNet.

Oxidative stress in fetuses with decompensated alloimmune hemolytic disease of the fetus and newborn (HDFN).
Hemolytic disease of the fetus and newborn (HDFN) from anti-D and other antibodies still affects 3-4 cases per 1000 births. Free radical damage from oxidative stress may contribute to the anemia of HDFN by damaging formed red blood cells. The proposed study is designed to identify oxidant stresses in fetuses diagnosed with HDFN.

Natural history registry for pregnancies complicated by prenatally diagnosed lower urinary tract obstruction (LUTO) with normal amniotic fluid volume.
Untreated, early midgestation LUTO with oligo/anhydramnios has a very high mortality and renal/pulmonary morbidity in the rare survivor. Prenatal intervention in carefully selected cases has improved survival and reduced pulmonary and renal morbidity. Presently, invasive fetal therapy for LUTO is only justified in the presence of concomitant oligohydramnios. Nothing is documented about the natural history and morbidity or mortality for fetuses with early midgestation LUTO and normal amniotic fluid volumes. A registry of cases with LUTO and normal amniotic fluid could serve as the basis to justify a prospective, randomized trial of shunting versus non-shunting in this population if significant morbidity is found.

Prenatal cytogenetic diagnosis by array-based copy number analysis.
Prenatal Cytogenetic Diagnosis by Array-Based Copy Number Analysis:This multicenter, prospective observational cohort study will compare clinical diagnostic results obtained by conventional cytogenetic microscopy (CC) analysis with those achieved by microarray analysis (MA).  The prenatal diagnostic samples will come from two categories of pregnancies: 1750 patients undergoing prenatal testing for standard indications (Group 1) and another 2250 pregnancies (Group 2) in which testing is performed on account of ultrasound detection of at least one pre-specified fetal structural or growth anomaly, or two or more other unlisted anomalies. The main objective of this multi-center collaborative study is to evaluate the accuracy, efficacy and clinical advantages of prenatal diagnosis using array-based copy number (microarray) analysis as compared with conventional cytogenetic (CC) analysis using microscopy.

Determination of the accuracy of free fetal DNA in maternal plasma in the assessment of the fetal RhD blood type. (STUDY COMPLETED)
Genetic analysis of free fetal DNA in maternal plasma will open the door to major advances in prenatal diagnosis while minimizing potential risks to the pregnancy.  Early efforts have been centered in Europe and the United Kingdom on determination of fetal gender and Rh blood type.  This investigation, sponsored by the Sequenom company, will seek to determine the accuracy of a new assay for fetal gender and RhD typing in the United States.  The combined obstetrical populations of the NAFNet organization will allow the study to be completed in a timely fashion so that the assay can be validated and be available for North American patients.

TTTS pregnancies after laser therapy: Prediction of fetal/neonatal death.
Management options for severe Twin-to-twin Transfusion Syndrome (TTTS) include observation, termination of the pregnancy, amnioreduction, septostomy, endoscopic laser ablation of placental vessels and selective termination of a moribund twin fetus. Informed decisions, as well as directive- and non-directive counseling, imply a reasonable understanding of the natural evolution of the disease and the expected outcome for the various therapeutic interventions. Selective termination, in particular, requires accurate predictive indicators for each fetus, to allow a comparison with other therapies.  If selective termination is chosen, the decision as to which fetus should be targeted for termination should be made based on medical knowledge of the prediction of death. The aim of this study is to analyze predictive factors for fetal or neonatal death for pregnancies with twin-to-twin transfusion syndrome that were treated with endoscopic laser ablation of placental vessels.

Indications for delivery for twin to twin transfusion syndrome after SFLP.
Among live born infants treated for TTTS in utero by selective fetoscopic laser photocoagulation (SFLP) of placental vessels, complications of prematurity remain a major source of morbidity. Studies involving treatment of twin-twin transfusion have significant heterogeneity of gestational age at delivery. It is difficult to determine from the available literature the proportion of spontaneous versus preterm birth following PPROM versus clinically indicated delivery. This information would be of value for counseling families as well as for practitioners determining the timing of delivery. The purpose of this study is to determine the indications for delivery for TTTS after treatment with SFLP.

Natural history of stage I twin-to-twin transfusion syndrome.
Insufficient data exists regarding the behavior of TTTS diagnosed in its earliest stage.  While some cases reverse spontaneously, others progress rapidly.  Currently, there are no known maternal or fetal factors that predict resolution or progression.  Progression to higher stages is associated with worse outcomes.  Better defining the natural course of stage I TTTS could help identify patients who are more likely to progress to higher stages, and how rapidly that progression may occur.  Those patients could be offered definitive treatment such as laser photocoagulation, while those likely to resolve could be managed conservatively.  The goal of this study is to better define, through a multicenter retrospective observational study design, the behavior of Quintero stage I twin-twin transfusion syndrome (TTTS), to address unanswered questions regarding disease management, and to identify demographic, sonographic and echocardiographic predictors of disease behavior.

Standardized prenatal assessment of risk-stratification for fetuses with congenital diaphragmatic hernia.
Congenital diaphragmatic hernia (CDH) occurs in approximately 1 in 2,500 live births and accounts for about 8% of all congenital anomalies. Among the patients with isolated CDH, morbidity and mortality depend predominantly on the severity of pulmonary hypoplasia and pulmonary arterial hypertension. Survival rates in neonates with isolated CDH have improved due to advances in neonatal respiratory management. Improvements in prenatal imaging, earlier prenatal diagnosis, and protocoled perinatal care have led to better patient selection for perinatal intervention including fetal tracheal occlusion and early ECMO initiation. The present NAFTNet study aims to standardize all these measurements in different centers in the United States that are part of this group, in order to better classify the fetuses according to prognosis. After standardizing the methods, a reproducibility study will be performed and, then, further evaluation will be performed to analyze the accuracy of these prenatal predictors. In order to evaluate those objectives, we aim to perform a retrospective multicenter NAFTNet study. The present study will contribute not only for the standardization and evaluation of the prenatal methods in different NAFTNet centers, but also to initiate a discussion about the standardization of the postnatal management for a future prospective study, before selecting candidates for fetal endoscopic tracheal occlusion.

NAFTNet Retrospective Report on Dexamethasone and Fetal Heart Block.
Complete heart block (CAVB) occurs in 1-2% of anti-SSA positive pregnancies. The consequences of CAVB are significant: almost 20% die and 50% of the survivors require permanent cardiac pacing by age 1 year The mortality rate increases to 50-80% in the fetuses who develop dilated cardiomyopathy (DCM) or endocardial fibroelastosis (EFE). Anecdotal reports of treating “emerging” disease, including 1° and 2° AVB or isolated EFE, support treatment to prevent progression to “established” including CAVB and DCM. In addition, the American Heart Association guidelines for fetal therapy suggest the use of dexamethasone in fetuses with autoantibody positive second degree AV block (Level of evidence II/B) to hinder disease progression to CHB.  This is a retrospective study of all anti-SSA antibody positive pregnancies with fetal conduction system disease or myocardial dysfunction or EFE reported to the NAFTNet centers from January 1, 2010 to December 31, 2015.

Gastroschisis Outcome Of Delivery (GOOD) study
The objective of this study is to investigate the hypothesis that delivery at 36 0/7- 36 6/7 weeks in stable patients with gastroschisis is superior to observation and expectant management. To test this hypothesis, we will complete a randomized, prospective, multi-institutional trial across North American Fetal Therapy Network-affiliated institutions. Patients may be enrolled in the study any time prior to 34 weeks, but will be randomized at 34 weeks to delivery at 36 weeks or observation. The primary composite outcomes will include stillbirth, neonatal death prior to discharge, respiratory morbidity, and need for parenteral nutrition at 30 days.

Three-Arm Randomized Trial of Pessary, Vaginal Progesterone and Placebo for Preterm Birth Prevention in Twin-Twin Transfusion Syndrome Complicated by a Short Cervix Undergoing Fetoscopic Laser Surgery.
Fetoscopic laser surgery for twin-twin transfusion syndrome (TTTS) increases the risk of preterm delivery. Preterm birth remains the most important cause of neonatal mortality and long-term neurodevelopmental morbidities for the TTTS survivors. Short cervical length is known to be an important risk factor for spontaneous preterm birth and to occur more frequently in women with a TTTS. Although there is no evidence that progesterone reduces the risk of preterm birth in TTTS or in multifetal gestation, there is evidence that progesterone reduces the risk of prematurity in singleton gestations complicated with a short cervix. The Arabin pessary has also been shown to reduce the risk of preterm birth in TTTS with short cervix undergoing FLS in a small retrospective study. This is a randomized trial evaluating the use of micronized vaginal progesterone or pessary versus control (placebo) to prevent early preterm birth in women carrying twins and with a cervical length of less than 30 millimeters.

Cardiovascular risk predictors in High Output Cardiac States: Twin-Reversed Arterial Perfusion & Sacrococcygeal Teratoma.
While TRAP and SCT are two very different disease entities, they share a common cardiovascular pathophysiology and may both lead to high-output cardiac failure. Recent reports suggest that TRAP complicates up to 3% of all monochorionic twin pregnancies; it is therefore considerably more common than formerly estimated. While the exact initiating mechanisms remain unknown, two elements are prerequisite: (i) The presence of arterio-arterial and veno-venous anastomoses. (ii) A hemodynamic advantage must arise for one (‘pump’) twin causing a reversal of the circulation in the second (‘perfused’) twin. This is a prospective observational cohort study. Subjects with either TRAP or SCT will undergo standard-of-care treatment in the participating centers. Cardiovascular parameters will be obtained at diagnosis and as frequently as once weekly, depending on clinical care standards and patient clinical needs and are part of the routine assessment. No additional ultrasound scans will be performed for women enrolled in the study. Pregnancies will be followed until delivery.

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