[Risk of very preterm delivery: can we refrain from in utero transfer and manage these patients in level I and II maternity wards?]. / Menace d'accouchement prématuré sévère précoce: est-il licite de ne pas transférer in utero et comment gérer une naissance en centre de niveau I et II?

The frequency of premature delivery is estimated at 0.5% of births (approximately 2000 per year in France). The rate of in utero transfers before 28 weeks, although difficult to evaluate, is well above this percentage, raising the risk of overloading level III maternity wards. Who should or should not be transferred? What tests are most pertinent? What are the criteria for diagnosing premature labor? Which treatment should be offered? How should the decision to transfer be established? What information should be furnished to the parents? How should an unexpected delivery be managed? How should the transfer network be optimally organized?

[Alternatives to amniocentesis for maternal age]. / Les alternatives à l'amniocentèse pour âge maternel.

Screening strategies of Down's syndrome should be re-evaluated. Amniocentesis for advanced maternal age has been proposed in the 70's because no other screening test was available. Maternal serum screening and first trimester nuchal translucency are now well validated, including in women over 38. The sequential and independent use of different screening tests leads to a dramatic increase of the false positive rate and thus of iatrogenic fetal losses. Maternal age remains the major risk factor for chromosomal anomalies, but it should be included in risk calculation strategies (ideally combining serum screening and nuchal translucency), and not taken as an isolated information. These screening strategies require strict quality control and audit, which is currently better achieved with serum screening than ultrasound screening. A complete information about Down's syndrome screening strategies should be given to women, regardless of their age, and their personal choice should be respected. For women of advanced maternal age, a policy of selective rather than routine amniocentesis is likely to reduce the risk of iatrogenic fetal loss and yet to allow for a reasonable sensitivity.

Circulating procoagulant microparticles in women with unexplained pregnancy loss: a new insight.

One of the frequently proposed mechanisms for pregnancy losses refers to uteroplacental thrombosis. However the contribution of classical thrombotic risk factors remains questionable and, if real, does not account for a large number of pregnancy losses. The aim of this study was to investigate the presence of circulating procoagulant microparticles, a new marker of cell activation already associated with various prothrombotic clinical settings. Microparticles were assessed by an original prothrombinase assay on platelet depleted plasma obtained from 74 women with a history of pregnancy loss without apparent cause and 50 controls. Patients were studied at least 2 months after the last obstetrical event and were classified into 2 groups: 49 women with at least 3 consecutive spontaneous abortions at or before the 10th postmenstrual week and 25 with at least one fetal death beyond the 10th postmenstrual week. Among the 74 patients, 41 had increased levels of circulating microparticles, 29 belonging to the group of early pregnancy loss (59%) and 12 to the group of late pregnancy loss (48%). The high prevalence of increased levels of procoagulant microparticles in both groups makes this new marker very promising for the understanding, follow up and therapeutical handling of pregnancy loss.

Localization of the Th2 cytokines IL-3, IL-4, IL-10 at the fetomaternal interface during human and murine pregnancy and lack of requirement for Fas/Fas ligand interaction for a successful allogeneic pregnancy.

PROBLEM: Th2 cytokines and Fas/Fas ligand interactions are proposed to be part of the placental barrier that contribute to the success of allogeneic pregnancy. To fully understand the role regulation of Th2 cytokines, we must isolate and identify the cells that produce them. We also need to assess the requirement for Fas/Fas ligand interaction in facilitating a successful allogeneic pregnancy. METHOD OF STUDY: To assess the site of production of Th2 cytokines, we used immunohistochemistry sections from placental and decidual tissue obtained at various stages of gestation in mice and humans. We used mice that are genetically deficient in Fas/Fas ligand interactions and raised specific anti-paternal CTLs by anti-paternal immunization of the mother before mating. RESULTS: The detailed results show that in both species the bulk of Th2 production may come from non-lymphoid tissues in the placenta and decidua, with a major role for trophoblasts. This raises questions about the mechanism(s) by which alloimmunization enhances local Th2 cytokine production. This issue is discussed. CONCLUSIONS: The success of allopregnancy in mice with circulating anti-paternal CTLs and deficient Fas/Fas ligand interactions rules out a mandatory role for such a mechanism in ensuring the success of allogeneic pregnancy.