Biomaterial Database

Second- and third-trimester ultrasound evaluation of chorionicity and amnionicity in twin pregnancy. A simple algorithm. 2000

A Monteagudo, and I E Timor-Tritsch

Bellevue Hospital, New York, New York, USA. ana.monteagudo@med.nyu.edu

OBJECTIVE To develop a simple and systematic algorithm to determine chorionicity and amnionicity in the second and third trimester by ultrasound. METHODS The algorithm was constructed based upon years of experience in examining multifetal pregnancies and by adopting the different sonographic signs suggested in the literature. RESULTS The following parameters were used to construct the algorithm: sexing of the fetuses, placental location, and origin, thickness and number of layers of the membranes. CONCLUSIONS The flow chart developed is simple to use and embodies all possible sonographic parameters to help determine chorionicity and amnionicity in the second and third trimester.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D011262	Pregnancy Trimester, Second	The middle third of a human PREGNANCY, from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation.	Midtrimester,Pregnancy, Second Trimester,Trimester, Second,Midtrimesters,Pregnancies, Second Trimester,Pregnancy Trimesters, Second,Second Pregnancy Trimester,Second Pregnancy Trimesters,Second Trimester,Second Trimester Pregnancies,Second Trimester Pregnancy,Second Trimesters,Trimesters, Second
D011263	Pregnancy Trimester, Third	The last third of a human PREGNANCY, from the beginning of the 29th through the 42nd completed week (197 to 294 days) of gestation.	Pregnancy, Third Trimester,Trimester, Third,Last Trimester,Last Trimesters,Pregnancies, Third Trimester,Pregnancy Trimesters, Third,Third Pregnancy Trimester,Third Pregnancy Trimesters,Third Trimester,Third Trimester Pregnancies,Third Trimester Pregnancy,Third Trimesters,Trimester, Last,Trimesters, Last,Trimesters, Third
D011272	Pregnancy, Multiple	The condition of carrying two or more FETUSES simultaneously.	Multiple Pregnancy,Multiple Pregnancies,Pregnancies, Multiple
D002823	Chorion	The outermost extra-embryonic membrane surrounding the developing embryo. In REPTILES and BIRDS, it adheres to the shell and allows exchange of gases between the egg and its environment. In MAMMALS, the chorion evolves into the fetal contribution of the PLACENTA.	Chorions
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000465	Algorithms	A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.	Algorithm
D000650	Amnion	The innermost membranous sac that surrounds and protects the developing embryo which is bathed in the AMNIOTIC FLUID. Amnion cells are secretory EPITHELIAL CELLS and contribute to the amniotic fluid.	Amniotic Membrane,Amnions,Amniotic Membranes,Membrane, Amniotic,Membranes, Amniotic