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At least 253 records · Page 14Linked to original sources

Clinical measures of gestational age in normal pregnancies.

Obstetric findings in 89 healthy women were evaluated prospectively by one obstetrician unaware of menstrual history. With weekly examinations, fetal heart tones were audible by fetoscope at 17.1 +/- 1.1 weeks' gestation (mean +/- SD) and the fundus reached the umbilicus at 16.6 +/- 0.9 weeks. At 20 to 31 weeks, fundal height in centimeters equaled weeks' gestation (confidence interval: +/- 3 weeks). The accuracy of predicting delivery date from combined findings (SD: 11.4 days) approached that from reliable menstrual history (SD: 10.2 days). Gestational age at delivery minus the pediatric Dubowitz estimate was 0.4 +/- 1.7 weeks. Gestational age may be overestimated by up to six weeks by assuming that the fundus reaches the umbilicus or that fetal heart tones appear at 20 weeks. However, carefully derived obstetric estimates potentially may be more reliable than pediatric estimates.

Delivery, Obstetric↗

Value of fetoscopy in prenatal diagnosis.

A technique of fetoscopy and fetoscopic blood sampling is described that makes maximum use of ultrasound scanning. A particle size analyser is also an integral part of the procedure. The results are based on 170 fetoscopies, 85 of which were performed for diagnostic reasons. The anterior placenta is rarely a cause of failure and in many instances makes fetal blood sampling easier. Pure fetal blood is obtainable from the umbilical cord insertion in 95% of cases sampled after 18 weeks' gestation. Fetal mortality may be as low as 3% and long-term adverse sequelae have not yet been discovered.

Congenital Abnormalities↗

[The antenatal diagnosis of haemoglobinopathies. A preliminary study (author's transl)].

From now on antenatal diagnosis of haemoglobinopathies is possible. Fetal blood can be taken from the uterus from the 17th to the 20th week of the pregnancy by direct puncture of the placenta or placentocentesis or by selective puncture of a straight vein close to its insertion in the cord on the fetal surface of the placenta, using a fetoscope. Biochemical techniques today allow us to detect beta thalassaemia major (with total absence of synthesis or with synthesis of less than 2 per cent of the beta A chain of haemoglobin by the fetus) and drepanocytosis (which is the synthesis of the chain beta S by the in the absence of production of the chain beta A). It is possible in cases where the fetal blood that has been taken is seriously contaminated by maternal blood (which is often the case with direct punctures) by using purification methods to increase the proportion of fetal red blood cells in the sample by eliminating adult reticulocytes which could cause errors in diagnosis. There are several centres where this type of diagnosis is being carried out. Some of them now have two years' experience and their results are encouraging. In spite of their difficulty these methods of investigation can allow couples at risk to have normal children or heterozygous infants. They can help them to avoid the need for termination of pregnancy or permanent contraception.

Anemia, Sickle Cell↗

Fetal obstructive uropathy.

Congenital obstructive uropathy is a relatively common developmental malformation, and severely affected fetuses die soon after birth from oligohydramnios-induced pulmonary hypoplasia or renal failure. Prenatal ultrasonography can reliably diagnose the specific anatomic defect, and using fetal urine sampling we can determine the extent of renal damage in utero with reasonable certainty. With these diagnostic tools and an understanding of the natural history of congenital obstructive uropathy we can now make rational decisions regarding treatment. Clinical experience has demonstrated that the selected fetus may benefit from in utero decompression, either by percutaneous shunt placement or open fetal surgery. However, each of these procedures has certain risks that must be carefully weighed against the expected benefits. Future techniques using fetoscopic surgery may provide the ideal therapeutic approach.

Animals↗

[Fetoscopy. A new method in prenatal diagnosis (author's transl)].

Fetoscopes are now being developed which make possible the inspection of human fetuses as well as withdrawal of a fetal blood sample in the early mid-trimester of pregnancy. The preliminary experiences of several groups are presented in this report. In addition, a fetoscopy including fetal blood sampling in a 24 week pregnancy prior to therapeutic abortion is described. The first prenatal diagnoses which have been made using this novel technique, concern defects of the fetal erythrocytes (sickle cel Hb, thalassemia). The fetal blood sample that was obtained in the present case was studied by appropriate methods. As expected, there was no evidence of either of these anomalies.

Anemia, Sickle Cell↗

[Current trends and prospects of fetal neurosurgery].

Fetal surgery failed up to now to correct early in gestation nervous system pathologies before an irreversible damage occurs. The major hindrance is the induction of preterm labour considered for fetal surgery what rejection is for organ transplantation. Pharmacological tocolytic control seems an essential step before a routine surgery is established. In the meanwhile miniinvasive endoscopic surgery holds out the best promises, minimizing fetal and maternal stress. There are many convincing experimental evidences that endoscopic surgery may prevent secondary neurological damage of spinal cord in the myelomeningocele. Vascularized latissimus dorsi muscle flap or skin graft were effectively used, with endoscopic techniques, to create a protective patch to preserve the nervous tissue from mechanical and/or chemical damage. Endoscopic implant of neurons-rich grafts in damaged cerebral sites, with beneficial behavioural effects and increased learning capacity in the recipient animal with respect to controls, disclose further perspectives to fetoscopic surgery.

Animals↗

Changes in maternal serum alpha-fetoprotein levels associated with intrauterine genetic diagnostic procedures.

The amount of fetal-maternal transfusion during invasive intrauterine diagnostic instrumentation was determined by measuring the increase in maternal serum alpha-fetoprotein (delta AFP) caused by the procedure. Fetal liver biopsy or fetoscopy for purposes other than blood sampling caused a mean delta AFP of 11.4 ng/ml and 34.2 ng/ml, respectively. Fetoscopy with fetal blood sampling produced a mean delta AFP of 211.8 ng/ml, while fetoscopy followed by placentesis caused a mean delta AFP of 462.8 ng/ml (representing a 1.07 ml fetal-maternal transfusion). Although this magnitude of fetal-maternal transfusion is an acceptable risk for the fetus, it is a sufficient transfusion to cause blood cell antigen sensitization.

Biopsy, Needle↗

Techniques for in utero endoscopic surgery. A new approach for fetal intervention.

In utero open surgery can salvage many fetuses with life-threatening anomalies. This approach carries risks, especially from preterm labor induced by the hysterotomy incision. In an effort to decrease uterine injury during hysterotomy, we developed techniques for endoscopic manipulation of the fetus. We developed these methods in fetal lambs. The uterus was exposed and insufflated with CO2. As a model for in utero surgery, a simulated cleft lip was created and immediately repaired using intracorporeal suturing and knot-tying procedures. The techniques for endoscopic suture placement and knot-tying were based on microsurgical principles. We also designed and created several specialized instruments to facilitate precise work in this highly magnified surgical field. The novel techniques of endoscopic fetal surgery described here offer an alternate approach to fetal intervention. Our future goals include the application of these techniques to a nonhuman primate model and the development of percutaneous access methods.

Animals↗

Endoscopic intrauterine surgery in primates: overcoming technical obstacles.

Current protocols for fetal surgery require cesarean section and partial fetal extraction, both of which impart significant risks to the mother and fetus. Endoscopic fetal surgery is less invasive and will likely reduce some of these risks, but the technical difficulties and feasibility in a primate model have yet to be explored fully. Four pregnant baboons (95 days gestation) were anesthetized, their uteruses exposed via an abdominal incision, and blunt-tipped flanged endoscopic ports inserted. Amniotic fluid was removed, and warmed saline was infused to dilate the uterus. To evaluate instrumentation and wound closure, the tip of the snout was externalized and bilateral cleft lip-like defects made. The lips were then endoscopically repaired by suture (Endostitch, U.S. Surgical) or unique nonpenetrating clips (VCS, U.S. Surgical). The saline was then removed, amniotic fluid returned, and the ports carefully removed. After 4 weeks, the fetuses were delivered and evaluated. Eight cleft lip-like defects were successfully repaired in all four cases. Operative time averaged 83 min. No infections, amniotic leaks, or adhesions developed. Survival was 50% with two fetuses delivering within 48 hours postoperatively: one from preterm labor, the other with fetal demise from retroperitoneal hemorrhage after operative blunt abdominal trauma. We demonstrate the feasibility of endoscopic fetal surgery in primates. The use of blunt-tipped flanged ports provides a fluid tight seal and allows appropriate closure of the fetal membranes, but requires laparotomy and uterine exposure. Distension of the uterus with warmed saline affords a larger operating field, enhancing visualization and instrumentation of the fetus. Grasping the fetus through the exposed uterus gives excellent control for repair. However, such control is also needed in a percutaneous approach. Further instrumentation development is needed to accomplish similar control for the percutaneous approach.

Animals↗

Transcervical flexible endoscopy for first trimester embryonic/fetal evaluation.

OBJECTIVE: The aim of the study was to investigate the efficacy of flexible embryofetoscopy for visualization of the first trimester human embryo and fetus. METHOD: Twelve pregnant women scheduled for legal termination of pregnancy at 6-12 weeks' gestation were included in the study. A flexible fiber optic endoscope with an eyepiece connected to a monitor was used. The sterile endoscope was passed transcervically under ultrasound guidance through the chorion into the chorionic cavity. Embryos/fetuses were observed directly through the intact amniotic membrane. RESULT: Successful embryofetoscopies with clear visualization of the embryo or fetus were accomplished in 50% of cases. There were no procedure-related complications. CONCLUSION: Preliminary experience employing transcervical flexible embryofetoscopy for direct visualization of the first trimester human embryo and fetus suggest that this technique may be used for the early identification of congenital anomalies suspected by ultrasound and is expected to offer opportunities for embryo/fetal tissue sampling as well as for gene and cell therapies.

Adult↗

Prenatal diagnostic techniques. Chorionic villus sampling.

Chorionic villus sampling (CVS) is a new prenatal diagnostic technique which is performed in the first trimester of pregnancy. Traditional methods of prenatal diagnosis, including amniocentesis and fetoscopy, must be performed in the midtrimester. In concert with the development of DNA methods of fetal cell analysis, first trimester fetal diagnosis utilizing CVS offers many advantages over traditional mid-trimester techniques. In addition, CVS may potentially allow therapeutic intervention to prevent or ameliorate some congenital defects.

Amniocentesis↗

Transabdominal thin-gauge embryofetoscopy: a technique for early prenatal diagnosis and its use in the diagnosis of a case of Meckel-Gruber syndrome.

OBJECTIVE: Our aim was to develop and evaluate a transabdominal endoscopic technique to visualize the embryo or fetus with thin-gauge needles and submillimetric fiberoptic endoscopes. METHODS: Under ultrasonographic guidance, an 18- or 19-gauge thin-wall needle was introduced into the uterus of 28 patients undergoing first-trimester or early second-trimester termination of pregnancy. A 0.7 mm endoscope was threaded through the lumen of the needle after removal of the stylet. Visualization of the embryo-fetus was attempted before 14 weeks' gestation (n = 20). From 16 to 20 weeks (n = 8), the needle and endoscope were directed to the placental insertion of the umbilical cord, and a cordocentesis was performed. RESULTS: Excellent visualization of the surface anatomy of fetuses from 7 to 13 weeks was obtained in 85% of cases (17/20). A diagnosis of Meckel-Gruber syndrome was made at 11 weeks' menstrual age by visualizing postaxial polydactyly and an occipital encephalocele. Endoscopically assisted cordocentesis allowed visualization of the lumen of the umbilical vein and of the blood flow within it. CONCLUSION: Endoscopic visualization of the embryo or fetus can be performed transabdominally in the first trimester with small-delivered endoscopes. This represents a clear advantage over previous endoscopic approaches to the human pregnancy. Potential applications of this technique include a precise description of fetal anatomy and physiologic features, diagnosis of anomalies, and therapeutic fetal interventions.

Abdomen↗