Guidelines for obstetrical practice in Japan: Japan Society of Obstetrics and Gynecology and Japan Association of Obstetricians and Gynecologists 2020 edition.

The 2017 clinical guidelines for obstetrical practice by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists were revised and published as the 2020 edition (in Japanese). The aim of these guidelines is to present appropriate standard obstetric diagnosis and management procedures that have reached consensus among Japanese obstetricians. The 2020 guidelines include 113 clinical questions and an appendix, followed by answers (CQ&A; originally 112 in the 2017 edition), a discussion, list of references, and some tables and figures presenting common problems and questions encountered in obstetrical practice. Each answer comes with a recommendation level of A, B, or C and has been prepared based principally on evidence or a consensus among Japanese obstetricians in situations where "evidence" is weak or lacking. Answers with a recommendation level of A or B represent current standard care practices in Japan. All 113 CQ&As and the appendix are presented here to promote a better understanding of the current standard care practices for pregnant and lactating women in Japan.

The role of placental indoleamine 2,3-dioxygenase in human pregnancy

Munn et al. made a scientific observation of major biological importance. For the first time they showed that in the mammal the fetus does survive an immune attack mounted by the mother, and that the mechanism responsible for the survival depends on the fetus and placenta 'actively' defending itself from attack by maternal T cells by means of an enzyme indoleamine 2,3-dioxygenase (EC 1.13.11.42) dependent localised depletion of L-tryptophan. These findings raise critical questions for disease and its prevention during human pregnancy. Specifically, the role of this mechanism (discovered in mouse) in the human, and the extent to which defective activation of this process is responsible for major clinical diseases are unknown. Therefore some key facts about this enzyme expressed in the human placenta have been studied in order to test whether Munn et al.'s findings in mouse are met for human pregnancy. This short review attempts to describe our experimental work on human placental indoleamine 2,3-dioxygenase.