A retrospective review of sonograms performed on 75 twin gestations was performed to evaluate the ability of sonography to distinguish monochorionic from dichorionic gestations based on the thickness of the membrane separating the fetuses. Clinical or pathologic evidence of chorionicity and amnionicity was available in all cases. A thick membrane had a predictive value of 83% for dichorionicity and was seen in 89% of the first sonograms obtained on dichorionic gestations. Of third trimester dichorionic pregnancies, a thick membrane was seen in only 52%. A thin membrane on the initial study had a predictive value for monochorionic diamniotic pregnancy of 83%, but was seen in only 54% of cases. There was 100% intraobserver and 91% interobserver concordance in interpretation of membrane thickness. Technical factors important in interpretation of membrane thickness are discussed. The appearance of the membrane can be useful in sonographic evaluation of chorionicity and amnionicity in twin gestations, but should be used in conjunction with all other information available.
We reviewed high-resolution real-time sonographic images (especially selected for a lack of technical artifacts) of the fetal spine of 46 normal fetuses between 18-27 menstrual weeks of development. The degree of visible posterior neural arch ossification was graded and compared with the gestational age. Recognizable early ossification of the laminae was seen in the cervical region of all fetuses studied. Similar ossification followed sequentially in the thoracic, lumbar, and sacral regions; however, sonographically recognizable ossification of the laminae in the lumbar spine was delayed until 22-24 weeks and in the sacral spine until 25 weeks or more. Awareness of these features will help to prevent false-positive diagnoses of dysraphism and, conversely, hopefully augment our ability to detect such lesions.
The twin-twin transfusion syndrome, associated with acute polyhydramnios in the 18th to 28th week of gestation, has a high perinatal mortality rate. Patients managed without intervention have essentially a 100% mortality rate for the involved twins. Different methods of intervention have been described, including therapeutic amniocentesis, selective feticide, and placental vessel puncture. In this case report we describe selective removal of one twin at 21 weeks of gestation by hysterotomy in a patient with the twin-twin transfusion syndrome.
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.
An attempt has been made to begin delineation of the in utero dynamics of fetal intracranial fluid in the presence of brain malformations. In a series of patients with fetal CNS defects, cephalocentesis was performed at the time of therapeutic abortion or to facilitate vaginal delivery. Intracranial CSF pressures and volumes were quite variable. There did not appear to be any discernible correlation between the type of lesion and the intracranial pressure. Fetal CSF glucose levels were moderately depressed and protein concentrations were very high. Neither virus nor bacteria were cultured from fetal CSF or amniotic fluid of any patients in this series.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.