title: Zygosity and placental anatomy in 15 consecutive sets of spontaneously conceived triplets.
abstract: Most triplets are trizygotic because they result from assisted reproduction. Prognosis is generally good. We analyzed 15 sets of triplets who were conceived spontaneously. Six sets were monozygotic, 7 were dizygotic, and only 2 sets were trizygotic. Considered as 45 twin pairs, 25 pairs (56%) were monozygotic. Twenty percent of these twins died as a result of twin-twin transfusion. Spontaneously conceived triplets have high risks compared with those resulting from assisted reproduction. These risks result from a high proportion of monozygotic embryos, many of whom have monochorionic placentas with vascular anastomoses, causing twin-to-twin transfusion.
authors: Department of Laboratory Medicine and Pathology, University of Alberta Hospitals, Edmonton, Canada.
authors: G A
authors: GA
authors: Machin
authors: F
authors: F
authors: Bamforth
mesh_terms: D001724:Birth Weight; D002823:Chorion / Q000033:anatomy & histology / Q000737:chemistry / Q000502:physiology; D004247:DNA / Q000032:analysis; D005260:Female; D005306:Fertilization; D005330:Fetofetal Transfusion / Q000401:mortality; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D012099:Reproductive Techniques; D014310:Triplets / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics
chemical_list: D004247:DNA