Martin J C van Gemert1, Jeroen P H M van den Wijngaard1,2, Frank P H A Vandenbussche3. 1. Department of Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, The Netherlands. 2. Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands. 3. Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, The Netherlands.
Abstract
BACKGROUND: Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack a functional heart but nevertheless show fetal growth because the normal pump twin perfuses the acardiac body through arterioarterial (AA) and venovenous (VV) anastomoses. The widely accepted 1% monochorionic acardiac incidence dates back to 1944 and the associated 1:35,000 pregnancies to 1953. Our aim was to update this analysis. METHODS: We accepted the 1% (actually 1.1%) monochorionic acardiac incidence due to lack of more precise data, included the recently observed 58% early cessation of acardiac development as well as consequences of assisted reproductive technology, and assessed the incidence of acardiac twinning under conditions of AA-VV anastomoses. RESULTS: Early acardiac monochorionic twinning increased from 1.1% to 1.1/(1-0.58) = 2.6%, from 1:35,000 to 1:9,500 to 11,000 pregnancies, depending on number and method of assisted reproductive technology, and occurs in approximately 1:8 AA-VV anastomoses-containing monochorionic placentas. CONCLUSION: Early acardiac twinning is not a rare event. The 1944-based 1% acardiac monochorionic incidence has a weak basis and could therefore be (much) larger. Knowing this incidence more precisely may contribute to our knowledge of embryonic splitting in unequal cell masses.
BACKGROUND: Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack a functional heart but nevertheless show fetal growth because the normal pump twin perfuses the acardiac body through arterioarterial (AA) and venovenous (VV) anastomoses. The widely accepted 1% monochorionic acardiac incidence dates back to 1944 and the associated 1:35,000 pregnancies to 1953. Our aim was to update this analysis. METHODS: We accepted the 1% (actually 1.1%) monochorionic acardiac incidence due to lack of more precise data, included the recently observed 58% early cessation of acardiac development as well as consequences of assisted reproductive technology, and assessed the incidence of acardiac twinning under conditions of AA-VV anastomoses. RESULTS: Early acardiac monochorionic twinning increased from 1.1% to 1.1/(1-0.58) = 2.6%, from 1:35,000 to 1:9,500 to 11,000 pregnancies, depending on number and method of assisted reproductive technology, and occurs in approximately 1:8 AA-VV anastomoses-containing monochorionic placentas. CONCLUSION: Early acardiac twinning is not a rare event. The 1944-based 1% acardiac monochorionic incidence has a weak basis and could therefore be (much) larger. Knowing this incidence more precisely may contribute to our knowledge of embryonic splitting in unequal cell masses.
Authors: Martin J C van Gemert; Michael G Ross; Jeroen P H M van den Wijngaard; Peter G J Nikkels Journal: Birth Defects Res Date: 2021-12-20 Impact factor: 2.661
Authors: Lan Zhang; Hongli Liu; Shuai Huang; Chao Tong; Zhigang Wang; Hongbo Qi; Philip N Baker; Mark D Kilby Journal: Front Med (Lausanne) Date: 2022-04-14
Authors: Martin J C van Gemert; Cees W M van der Geld; Michael G Ross; Peter G J Nikkels; Jeroen P H M van den Wijngaard Journal: Birth Defects Res Date: 2021-05-17 Impact factor: 2.344