O Shen1, A Samueloff1, U Beller1, R Rabinowitz1. 1. Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Jerusalem, Israel.
Abstract
OBJECTIVE: To determine the relationship between amnionicity and number of yolk sacs before 11 weeks of gestation. METHODS: Twenty-two cases of monochorionic multiple pregnancy were scanned before 11 weeks of gestation. There were 21 sets of twins and one of triplets. Amnionicity was determined by visualization of a dividing amniotic membrane between the gestational sacs. The number of yolk sacs was recorded and compared with the presence or absence of a dividing membrane for all fetuses. RESULTS: In 17/20 (85%) cases of monochorionic diamniotic twins, two yolk sacs were seen. In 3/20 (15%) cases of monochorionic diamniotic twins, a single yolk sac was seen. In the one case of monochorionic diamniotic triplets, two yolk sacs were visualized. In one case of monoamniotic twins, a single yolk sac was observed. CONCLUSIONS: In monochorionic pregnancies, the presence of two yolk sacs predicts diamnionicity. However, the use of the number of yolk sacs as a predictor of amnionicity may not be accurate in a small proportion of patients. The diagnosis of monoamnionicity can be made only following a careful search for a dividing amniotic membrane. Copyright 2005 ISUOG.
OBJECTIVE: To determine the relationship between amnionicity and number of yolk sacs before 11 weeks of gestation. METHODS: Twenty-two cases of monochorionic multiple pregnancy were scanned before 11 weeks of gestation. There were 21 sets of twins and one of triplets. Amnionicity was determined by visualization of a dividing amniotic membrane between the gestational sacs. The number of yolk sacs was recorded and compared with the presence or absence of a dividing membrane for all fetuses. RESULTS: In 17/20 (85%) cases of monochorionic diamniotic twins, two yolk sacs were seen. In 3/20 (15%) cases of monochorionic diamniotic twins, a single yolk sac was seen. In the one case of monochorionic diamniotic triplets, two yolk sacs were visualized. In one case of monoamniotic twins, a single yolk sac was observed. CONCLUSIONS: In monochorionic pregnancies, the presence of two yolk sacs predicts diamnionicity. However, the use of the number of yolk sacs as a predictor of amnionicity may not be accurate in a small proportion of patients. The diagnosis of monoamnionicity can be made only following a careful search for a dividing amniotic membrane. Copyright 2005 ISUOG.
Authors: Jet Bliek; Marielle Alders; Saskia M Maas; Roelof-Jan Oostra; Deborah M Mackay; Karin van der Lip; Johnatan L Callaway; Alice Brooks; Sandra van 't Padje; Andries Westerveld; Nico J Leschot; Marcel M A M Mannens Journal: Eur J Hum Genet Date: 2009-06-10 Impact factor: 4.246