Comparing maternal and neonatal outcomes between hands-and-knees delivery position and supine position

Background:The supine position is the most common birth position adopted in China,but the World Health Organization recommends non-supine positions for delivery.The handsand-knees position shows several advantages,such as wide pelvic diameter and easy fetal rotation during delivery.Small trials conducted in China in 2011 revealed that the handsand-knees position resulted in improved maternal and neonate outcomes than those in the supine position.However,a comprehensive study must be conducted before the handsand-knees position can be introduced into clinical practice.Hence,we conducted this multicenter trial to comprehensively examine the benefits of the hands-and-knees position over the supine position during delivery.Methods:Our clinical study was conducted in 11 hospitals in China from May to December 2012.A total of 446 pregnant women who gave birth in the hands-and-knees position were assigned into the experimental group,and 440 women who gave birth in the supine position were classified into the control group.Episiotomy rate was evaluated as the primary outcome,and perineum laceration degree was considered the secondary outcome.Results:Women in the experimental group achieved lower rates of episiotomy and higher rates of intact perineum and first-degree perineum lacerations compared with those in the control.Postpartum bleeding amount,neonatal asphyxia,and APGAR scores at 1 and 5 min were not significantly different between the two groups.Conclusions:This study proves that women who delivered in the hands-and-knees position achieved low rates of episiotomy and intact perineum.Moreover,the rates of neonatal asphyxia and postpartum bleeding did not increase.Pregnant patients who prefer to adopt the hands-and-knees position should be assisted in assuming such position during delivery.

Effect of thermophysical property and coating thickness on microstructure and characteristics of a casting

A new improved investment casting technology(IC) has been presented and compared with the existing IC technology such as lost foam casting(LFC). The effect of thermophysical property and coating thickness on casting solidification temperature field, microstructure and hardness has been investigated. The results show that the solidification rate decreases inversely with the coating thickness when the coating contains silica sol, zircon powder, mullite powder and defoaming agent. In contrast, the solid cooling rate increases as the coating thickness increases. However, the solidification rate and solid cooling rate of the casting produced by the existing IC and the improved IC are very similar when the coating thickness is 5 mm, so the microstructure and hardness of a container corner fitting produced by the improved IC and the existing IC are similar. The linear regression equation for the grain size(d) and cooling rate(v) of the castings is d= –0.41v+206.1. The linear regression equation for the content of pearlite(w) and solid cooling rate(t) is w=1.79 t + 6.71. The new improved IC can greatly simplify the process and decrease the cost of production compared with the existing IC. Contrasting with LFC, container corner fittings produced by the new improved IC have fewer defects and better properties. It was also found that the desired microstructure and properties can be obtained by changing the thermophysical property and thickness of the coating.

Normal Range of Head-to-body Delivery Interval by Two-step Delivery

Background： The one-step method was routine practices in China, scientific evidence to support this intervention is scarce. The purpose of this study was to observe the natural process of head-to-body delivery interval by waiting for at least one contraction （two-step） after head delivered in normal birth. Methods： From March 1 to March 30 in 2015 at Haikou Maternal and Child Hospital in China, normal vaginal birth with normal baby condition were recorded by video. Videotapes were transferred to computer then replayed and observed. Results： Ninety-two cases were enrolled in this study. The average head-to-body delivery interval by two-step delivery was 71.04± 61.02 s, （mean ＋ 2 standard deviation - 193.07 s, 95% confidence interval [15.65-229.15] s）. Fifty-one patients （51/92, 55.43%） were 〈60 s, 41 patients （41/92, 44.57%） were over 60 s. Shoulders delivered at the first contraction were 96.74% （89/92）, 3.26% （3/92） had delivered by the second contraction. Shoulders emerged from perineum were 71.73% （66/92）, 15.21% （14/92） transversely, and 13.04% （12/92） emerged from under pubic arch. Babies cried before the shoulder were 31.52% （29/92）, cried after birth 52.17% （48/92）, and 16.30% （15/92） did not cry after birth. Baby activities included as making faces, sucking, and bubbled from mouth and noses, and the lighter blue color of skin with good perfusion. Conclusions： The average time of head-to-body delivery interval was longer than 60 s by two-step delivery. Majority shoulders were delivered at the first contraction. Majority shoulders emerged from perineum rather from under pubic arch. The routine one-step method of shoulder delivery where the downward force applied is not necessary and is not the right direction. Baby＇s breath, making faces, sucking, bubble from noses and mouth, and the light blue color of the faces, all those signs during shoulder delivery indicated a normal live birth.