| Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. | ||||
| Obstet Gynecol 2000 Apr;95(4):572-6 (ISSN: 0029-7844) | ||||
| Lee W; Lee VL; Kirk JS; Sloan CT; Smith RS; Comstock CH Divisions of Fetal Imaging and Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, William Beaumont Hospital, Royal Oak, MI 48073-6769, USA. wlee@beaumont.edu. |
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| OBJECTIVE: To describe the prenatal ultrasonographic
diagnosis, natural evolution, and clinical outcomes of vasa previa
in a large population at a single institution. METHODS: We attempted to view the internal cervical os of 93,874 women with second- and third-trimester pregnancies during an 8-year period. Echogenic parallel or circular lines near the cervix, seen by gray-scale ultrasonography, raised the possibility of vasa previa. Diagnosis was confirmed by Doppler and endovaginal studies if aberrant vessels over the internal cervical os were suspected. Abnormal placental morphology and velamentous cord insertion were documented if they were identified during prenatal scans. Ultrasonographic findings were correlated with clinical courses, perinatal outcomes, and placental pathology examinations. RESULTS: Eighteen cases of vasa previa were suspected at a mean (+/- standard deviation) gestational age of 26.0 +/- 6.3 weeks; the earliest diagnosis was at 15.6 weeks' gestation. Eight of those cases initially showed placental edge over the internal os and later developed vasa previa after the placenta "receded" from the cervix. Six women had mild vaginal bleeding at a mean gestational age of 31.3 weeks. Three women had normal late third-trimester scans and were allowed to have uncomplicated vaginal deliveries. The remaining subjects delivered by cesarean. There were two deaths (one fetal and one neonatal), and minor preterm complications slightly prolonged infant hospitalizations. One set of preterm twins needed neonatal transfusions. Pathology findings included ten cases of velamentous insertion and three cases each of bilobed placentas, succenturiate lobes, and marginal cord insertion. CONCLUSION: Vasa previa was detected in asymptomatic women as early as the second trimester. Perinatal outcome was generally favorable, although several infants had slightly extended newborn nursery admissions due to mild complications of prematurity. |
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| Indexing Check Tags: Female; Human; Male | ||||
| Language: English | ||||
| MEDLINE Indexing Date: 200006 | ||||
| Publication Type: JOURNAL ARTICLE | ||||
| PreMedline Identifier: 0010725492 | ||||
| Unique NLM Identifier: 20192111 | ||||
| Journal Code: A; M | ||||
| Found at: Knowledge Finder using the following key words: vasa previa |
Vasa previa: prenatal diagnosis, natural evolution,
and clinical outcome
Wesley Lee et al
Divisions of Fetal Imaging and Maternal-Fetal Medicine, Dept of Obstetrics and
Gynaecology, William Beaumont Hospital, Royal Oak, Michigan, USA
Obstet Gynecol 2000; 95:572-576
The antenatal diagnosis of vasa previa enables careful monitoring of the aberrant vasculature over the internal cervical os. These vessels are prone to laceration following membrane rupture with catastrophic results. During labor, compression of these vessels can cause fetal bradycardia. Vasa previa is usually caused by velamentous insertion of the umbilical cord but may also be associated with bilobed or succenturiate placentas. In all cases, either fetal or placental vessels cross over the internal os. A significant reduction in fetal loss rate and fetal transfusion can be achieved if vasa previa is diagnosed before vaginal delivery is attempted. Prenatal detection enables elective cesarean under circumstances that provide the necessary additional care.
Over an eight-year period, researchers in Michigan found 18 cases of vasa previa using ultrasound imaging. The earliest diagnosis was made at just under 16 weeks’ gestation and the mean diagnosis at 26 weeks’ gestation. Eight of the women with vasa previa had a low-lying placenta on an earlier scan and six experienced bleeding complications. Three women delivered vaginally because the late third-trimester ultrasound no longer showed vasa previa due to differential growth of uterus and placenta. Risk factors for vasa previa and their occurrence in this study - velamentous insertion (10), bilobed placenta (3), succenturiate placental lobe (3), multiple gestation (3 sets of twins) and marginal cord insertion (3).
The authors recommend at least one additional late third-trimester ultrasound to reassess the diagnosis prior to delivery. Ultrasound characteristics of vasa previa were described as echogenic linear or tubular structures representing aberrant vessels over or near the internal os. Suspicious findings were more recently checked with Doppler and colour Doppler and endovaginal when necessary. Other situations that might mimic vasa previa include chorioamniotic membrane separation, normal cord loop and marginal placental venous sinus. ‘Vasa previa was detected in asymptomatic women as early as the second trimester. Perinatal outcome was generally favorable, although several infants had slightly extended new-born nursery admissions due to mild complications of prematurity,’ they concluded.
Source: http://www.obgyn.net/