Search

We report the third case of spontaneous monochorionic dizygous pregnancy, discovered on foetal sex discordance. Blood group testing on the female twin revealed a hematopoietic chimera. The mechanism of monochorionic dizygous formation could be the fusion of two independent zygotes at a late morula stage. A single placental mass with vascular anastomosis then develops. Stem cells exchanged during early foetal life can thus lead to chimeras, in similar conditions to stem cell transfusion in adults. Immaturity of the foetal immune system allows cell graft in the other twin's marrow. Assisted reproductive procedures are believed to promote such pregnancies., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Objectives: In a regional study of preterm infants born before 35weeks of gestation, the aim was to propose a new classification of preterm births into three groups, and to describe the pregnancy complications and fetal disorders in each group., Patients and Methods: In two areas covered by a perinatal network, all preterm births, live births and stillbirths, which occurred between 22 and 34 completed weeks were recorded over a 21-month period. Each case was classified either in the medically-indicated preterm birth (I) group, or in the accepted spontaneous preterm birth (ASp) group or in the non-accepted spontaneous preterm birth (NASp) group., Results: One thousand and sixty cases of preterm births were included; among them, 981 were live births or ended with per partum infant death. Forty-nine percent of these births were medically indicated, 32 % were ASp and 19 % were NASp. The distribution of pregnancy complications and fetal disorders differed between preterm birth groups: ischemic placental diseases were present in 38,2 % of medically-indicated births; preterm premature rupture of membranes occurred twice more often in I and ASp preterm births than in NASp preterm births., Conclusion: This classification is based on the medical decision; it allows to compare medical practices in given obstetrical situations. It appears to be reproducible and easy to use., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)