Ryoma Hayashi

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Prenatal and intrapartum care provided to 1,181 women, all meeting risk requirements for nurse-midwifery care, by certified nurse-midwives (n = 471) and obstetricians (n = 710) are compared using indicators of physical and of educational/psychosocial components of maternity care. Data are from clinical records and questionnaires completed by the women.(More)
Risk assessment for preterm delivery remains difficult, particularly among women with no prior history of preterm birth. We hypothesized that accurate assessment of cervical length by endovaginal ultrasonography could predict preterm delivery risk. A total of 178 patients with singleton gestations and without cervical incompetence were studied with(More)
OBJECTIVE The purpose of this study was to test the hypothesis that infusion of the oxytocin antagonist atosiban results in decreased preterm uterine activity in the human. STUDY DESIGN A randomized, double-blind, placebo-controlled trial was performed. One hundred twenty women from 20 to 36 weeks' gestation with a complaint of labor who had more than(More)
The purpose of this study was to describe the course of preterm labor in patients receiving a standard intravenous infusion of the oxytocin antagonist atosiban. An open-labeled, non-randomized study was conducted at 4 sites. Successful tocolysis was defined as delay of delivery larger than 48 hours from starting atosiban and no need for an alternate(More)
We characterized the innervation of human myometrial tissues by electrical field stimulation and electron microscopy. Nerve-specific parameters (pulse duration 0.6 msec) were used for electrical field stimulation to selectively activate intrinsic nerves. In specimens from nonpregnant, nonparous women (n = 6), tetrodotoxin (10(-6) mol/L) significantly(More)
OBJECTIVE To prospectively determine whether moderate exercise during pregnancy lowers blood pressure. STUDY DESIGN A randomized, controlled trial with one test group and one control group. All subjects have a history of mild hypertension, gestational hypertensive disorders or a family history of hypertensive disorders. Subjects were recruited before 14(More)
OBJECTIVE To determine whether pregnancy outcomes differ by provider group when alternative explanations are taken into account. METHODS Pregnancy outcomes were compared for 710 women cared for by private obstetricians and 471 cared for by certified nurse-midwives. At intake, all women qualified for nurse-midwifery care. They were retained in their(More)
In a cohort analysis of Silastic vacuum extractor deliveries, 65% were completed with the vacuum extractor alone, 24% with outlet forceps, 3% with midforceps, and 7% with cesarean section (vacuum extractor-cesarean). Control groups were formed by using the next sequential forceps delivery, spontaneous vaginal delivery, and every second cesarean section(More)
OBJECTIVE To identify the fetal heart rate patterns that occurred in a 2-h period of time preceding uterine rupture. METHODS The fetal monitor strips and the medical records of patients with a confirmed diagnosis of uterine rupture were reviewed. These patients delivered at the University of Michigan Hospital from January 1, 1985 to December 31, 1999 and(More)
OBJECTIVE The objective of this study was to compare the cost-effectiveness of 9 strategies for the management of threatened preterm labor. STUDY DESIGN We derived 6 management options from the literature. These were (1) to treat all women with tocolytics and corticosteroids ("treat all"); (2) to treat all women while awaiting results of the "traditional"(More)