Objective To determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies.Design Systematic review and meta-analysis.Data sources Medline, Embase, and Cochrane databases (until December 2015). Review methods Databases were searched without language restrictions for studies of women with uncomplicated twin pregnancies that reported rates of stillbirth and neonatal outcomes at various gestational ages. Pregnancies with unclear chorionicity, monoamnionicity, and twin to twin transfusion syndrome were excluded. Meta-analyses of observational studies and cohorts nested within randomised studies were undertaken. Prospective risk of stillbirth was computed for each study at a given week of gestation and compared with the risk of neonatal death among deliveries in the same week. Gestational age specific differences in risk were estimated for stillbirths and neonatal deaths in monochorionic and dichorionic twin pregnancies after 34 weeks’ gestation.Results 32 studies (29 685 dichorionic, 5486 monochorionic pregnancies) were included. In dichorionic twin pregnancies beyond 34 weeks (15 studies, 17 830 pregnancies), the prospective weekly risk of stillbirths from expectant management and the risk of neonatal death from delivery were balanced at 37 weeks’ gestation (risk difference 1.2/1000, 95% confidence interval −1.3 to 3.6; I2=0%). Delay in delivery by a week (to 38 weeks) led to an additional 8.8 perinatal deaths per 1000 pregnancies (95% confidence interval 3.6 to 14.0/1000; I2=0%) compared with the previous week. In monochorionic pregnancies beyond 34 weeks (13 studies, 2149 pregnancies), there was a trend towards an increase in stillbirths compared with neonatal deaths after 36 weeks, with an additional 2.5 per 1000 perinatal deaths, which was not significant (−12.4 to 17.4/1000; I2=0%). The rates of neonatal morbidity showed a consistent reduction with increasing gestational age in monochorionic and dichorionic pregnancies, and admission to the neonatal intensive care unit was the commonest neonatal complication. The actual risk of stillbirth near term might be higher than reported estimates because of the policy of planned delivery in twin pregnancies.Conclusions To minimise perinatal deaths, in uncomplicated dichorionic twin pregnancies delivery should be considered at 37 weeks’ gestation; in monochorionic pregnancies delivery should be considered at 36 weeks.Systematic review registration PROSPERO CRD42014007538.

The incidence of perinatal complications in 219 sets of MD twins managed from early gestational age to the neonatal period in one perinatal center was demonstrated. The incidence of TTTS was 8%; the survival rate was 89% at 28 days of age.

ObjeCtiveTo determine the risks of stillbirth and neonatal complications by gestational age in uncomplicated monochorionic and dichorionic twin pregnancies. DesignSystematic review and meta-analysis. Data sOurCesMedline, Embase, and Cochrane databases (until December 2015). review methODs Databases were searched without language restrictions for studies of women with uncomplicated twin pregnancies that reported rates of stillbirth and neonatal outcomes at various gestational ages. Pregnancies with unclear chorionicity, monoamnionicity, and twin to twin transfusion syndrome were excluded. Meta-analyses of observational studies and cohorts nested within randomised studies were undertaken. Prospective risk of stillbirth was computed for each study at a given week of gestation and compared with the risk of neonatal death among deliveries in the same week. Gestational age specific differences in risk were estimated for stillbirths and neonatal deaths in monochorionic and dichorionic twin pregnancies after 34 weeks' gestation. results 32 studies (29 685 dichorionic, 5486 monochorionic pregnancies) were included. In dichorionic twin pregnancies beyond 34 weeks (15 studies, 17 830 COnClusiOnsTo minimise perinatal deaths, in uncomplicated dichorionic twin pregnancies delivery should be considered at 37 weeks' gestation; in monochorionic pregnancies delivery should be considered at 36 weeks. systematiC review registratiOn PROSPERO CRD42014007538.

In the guinea pig, defecation is controlled by the myenteric plexus, whose activity is modulated by the sacral spinal and supraspinal centers. The purpose of this study is to clarify the control of defecation reflex by sympathetic nerves. The propulsive contractions of the rectum produced by rectal distension (recto-rectal excitatory reflex response) were abolished after transection of the Th 13 and/or L 4 segment. This response was reproduced again after removal of the lumbar segments (L1--4), division of the lumbar dorsal roots (L1--4), the lumbar splanchnic nerves or lumbar colonic nerves (LCN). The frequency of efferent discharges of LCN was increased slightly by rectal distension and remarkably increased after Th 13 and/or L 4 transection. Thus, there occurs during the recto-rectal reflex not only mucosal intrinsic reflex and sacral excitatory reflex via the pelvic nerves but also a lumbar inhibitory reflex via the colonic nerves, whose center may be located in the upper lumbar segments. But, the activity of the inhibitory center was depressed by the supraspinal center, so that an excitatory reflex is produced more dominantly than an inhibitory one in normal animals. All these extrinsic reflexes coordinate the activity of the myenteric plexus in defecation reflex.

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