Clinical guidelines for obstetrical practice were first published by the Japan Society of Obstetrics and Gynecology (JSOG) and the Japan Association of Obstetricians and Gynecologists (JAOG) in 2008, and a revised version was published in 2011. The aims of this publication include the determination of current standard care practices for pregnant women in Japan, the widespread use of standard care practices, the enhancement of safety in obstetrical practice, the reduction in burdens associated with medico-legal and medico-economical problems, and a better understanding between pregnant women and maternity-service providers. These guidelines include a total of 87 Clinical Questions followed by several Answers (CQ&A), a Discussion, a List of References, and some Tables and Figures covering common problems and questions encountered in obstetrical practice. Each answer with a recommendation level of A, B or C 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 87 CQ&A are presented herein to promote a better understanding of the current standard care practices for pregnant women in Japan.

Maternal bodyweight as well as eating habits established before pregnancy may have a considerable effect on fetal growth. There is an urgent need to improve the diet of Japanese women of child-bearing age, especially during pregnancy.

The aim of the present study was to investigate the relationship between assisted reproductive technology procedures, the morphology of the basal plate of placentas, and amount of bleeding in deliveries. Fifty-five whole placentas (fresh-embryo transfer in the in vitro fertilization cycle [n = 6], frozen-thawed embryo transfer in the natural cycle [n = 13] or in the hormonal cycle [n = 10], and age-matched spontaneously conceived pregnancies [n = 26]) were retrospectively enrolled and histologically analyzed. The whole placentas were stored in our pathological division among 512 singleton pregnancies with vaginal deliveries (34-41 weeks of gestation) at Hamamatsu University Hospital. The morphology of the placental basal plate was examined using Azan staining. A total of 20 digital images (each 0.53 mm(2)) of microscopic fields were analyzed per placenta to measure the mean values of the vertical maximum thickness of Rohr and Nitabuch fibrinoid layers and % loss of decidua. The thickness of Rohr fibrinoid layer and % loss of decidua were significantly higher in the frozen-thawed embryo transfer in the hormonal cycle group than in the frozen-thawed embryo transfer in the natural cycle and spontaneously conceived pregnancy groups (each P < .01). The z scores for both the thickness of Rohr fibrinoid layer and % loss of decidua positively correlated with those for the amount of bleeding in deliveries (P < .05 each). Assisted reproductive technology procedures changed the morphology of the placental basal plate, suggesting a possible association with an increase in the amount of bleeding in deliveries.

Chorangiosis is a vascular hyperplasia in the terminal chorionic villi, usually diagnosed histologically using the criteria of Altshuler. Its true etiology has not been fully identified, but chorangiosis has been proposed to result from a longstanding, rather low-grade hypoxia in the placental tissue. To clarify a possible association of placental oxygenation status with the development of chorangiosis, we measured placental tissue oxygen index (TOI) values using near-infrared spectroscopy (NIRS) before delivery and retrospectively compared them to the detection of placental chorangiosis, in a total of 47 (46 singleton and one set of dichorionic diamniotic twins) pregnant women. Small for gestational age (SGA) and/or maternal complications were observed in all cases of placental chorangiosis. Placental TOI values were significantly elevated in cases of chorangiosis. This indicates high oxygen saturation in the intervillous spaces because placental TOI values are expected to represent the oxygenation of maternal blood in the placental tissue. A possible preceding low efficiency of oxygen transfer to the fetal circulation in the villi might not only augment the oxygen saturation of maternal blood in intervillous spaces, but also cause rather low oxygenation in the capillaries of the villi and result in chorangiosis.

Objective: To classify the infants into 9 blocks based on the deviation of both placental weight (PW) and fetal/placental weight ratio (F/P) Z score and compared the incident rate of perinatal death in each of the small for date (SFD) vs. appropriate for date (AFD) vs. heavy for date (HFD) groups.Methods: The study population consisted of 93,034 placentas/infants from women who vaginally delivered a singleton infant. They were classified into 3 groups according to infants' weight: SFD (n=3,379), AFD (n=81,143) and HFD (n=8,512). The population was classified into 9 blocks according to the combination of i) low vs. middle vs. high placental weight (PW: a sex-, parity- and gestational-age-specific placental weight) and ii) low vs. middle vs. high F/P. In both i) and ii), ± 1.28 standard deviations in the in the Z scores was used for classifying low vs. middle vs. high, with 3x3 making 9 blocks. We then determined whether or not the perinatal death in each block differed among the three groups (SFD vs. AFD vs. HFD).Results: (1) The proportions of 'balanced growth of placenta and infant' (appropriate PW and F/P based on Z-score) were 37.6% in the SFD group, 78.8% in the AFD group, and 51.2% in HFD group. (2) The proportion of 'inappropriately heavy placenta' in the SFD group and that of 'inappropriately light placenta' in the HFD group were 0.3 and 0.4%, respectively, a very rare phenomenon. The proportions of 'inappropriately heavy placenta' and 'inappropriately light placenta' accounted for 4.1 and 5.5% in AFD group, respectively. (3) The rates of perinatal death in those with 'balanced growth of placenta and infant' were lowest in the SFD and AFD groups.Conclusion: By showing the fact that perinatal death was lowest in cases with balanced fetal/ placental growth, we conclude that 9-block categorization of PW and F/P based on deviation in the Z-score may be a candidate factor employable for understanding fetal and placental growth and perinatal deaths.