Initial Exploration Of Clinical Value Of Computerized LaborPro System In Pelvimetry And Labour Monitoring

The WHO proposed that cesarean section rate of any region should not exceed 10% to 15% in 1985. However, global cesarean section rate is still rising during the past 20 years[1,2], especially the non-medical indication ones. The trend of mortality and morbidity of gravida and fetus stagnated in this decade[3]. Cesarean delivery with medical indications has credited for the safety of both high-risk mother and perinatal fetus. Yet cesarean delivery for non-medical indications, particularly those in second stage of labor, would significantly increase complications and mortality of mothers and neonates[1,3-5].Reducing the cesarean section rate, especially the non-medical indications or primary ones, and increase the spontaneous delivery rate, have been a global issue, which still difficult to implement.The basis for successful spontaneous delivery is chiefly the four factors of uterine contractions, birth canal, fetal factors and maternal psychological fators.Currently, because of little variation of exact figures, big error of traditional measurements[6,7] and unclear clinical value of pelvimetry[8,9], prenatal prediction of delivery method is still imperfect on account of subjective error and lack of reliable evaluation standard in clinical assessments of cephalo-pelvic relationship. Except the traditional measuring method, taking into account the risk of fetal exposure to ionizing radiation, only nuclear magnetic resonance (MRI), Doppler ultrasound and various ancillary software system are considered safe now in obstetric field. Combining pelvimetry by MRI in the late trimester with fetal ultrasound measurement does help to select the mode of delivery to some extent, but not superior to traditional method in prediction of dystocia and its disadvantages of imaging and price limit its clinical promotions. Meanwhile, there’re some new parameters to be discovered, which closely related to dystocia.Altought there’ve some research reports about ultrasound pelvis measurement, its disadvantages, that imaging which susceptible to disturbance and high requirement for equipments and technicians, restrict the popularity. There’re no reports about computerized-assisted softwares, by far. Except for the inherent drawback of these methods, both the domestic and foreign researchs generally agress that female pelvis progressing toward the ones which against the spontaneous deliver].The judgment of abnormal labor is still mainly rely on traditional vaginal examination currently. Because the differences in personal experience, finger length, recognition capability of pelvic anatomic landmarks and lake of effective predictors for both shoulder dystocia and head-position dystocia, along with the interference by abnormal fetal position, molding of fetal head, caput succedaneum or cephallohematomal,this assessment method lack objectivity, which seems adverse to guaranteeing the security implementation of forceps and vacuum extraction.Friedman was the first to depict a labor curve and divide the labor process into several stages and phases in 1955. However, these criteria created 50 years ago may no longer be applicable to contemporary obstetric populations and for current obstetric management. Futhermore, the latest abroad studies found there’s some difference in labor progression. Williams Obstetrics 23rd defined the point separating an average starting point of active phase by 4-5cm. Zhang et al found that nulliparas and multiparas appeared to progress at a similar pace before 6 cm and after 6 cm labor accelerated much faster in multiparas than nulliparas.Thus, by imaging techniques, comprehensive analysis of delivery parameters is good for selecting reasonable delivery method and monitoring labor progression.We imported computerized LaborPro digital delivery monitor (Trig Medical Ltd, Yokneam, Israel) (hereinafter referred to as LP system), which use magnetic position trackers and ultrasound technology. The LP system, which has received both FDA (Food and Drug Administration) clearance and European CE conformity marking, allows determination of cephalopelvic disproportion, fetal head station and position using ultrasound and a position tracking system.Some foreign studies has done some pilot research in the accuracy of LP system in the determination of fetal head station and clinical assessment of cervical dilatation during active labor.At present there’re no relevant articles published inland, although some other hospitals have imploted this machine.In this study, our team has validated its high accuracy preliminary and is to compare LP system determination of pelvimetry, fetal head station and position with routine vaginal examination, and to explore the association between fetal head station and cervical dilatation during the active labor, as well as its clinical value.This study divided into 2 Parts:Part 1 Confirmatory analysis of the accuracy of computerized LaborPro system used in pelvimetry[Purpose]The purpose of this study was to compare the LP system determination of pelvimetry.[Methods]We select 299 singleton term pregnancies during the active phase of vertex, uncomplicated labor from January 2014 to May at Nanfang Hospital.Through different methods,261 cases experienced external pelvimetry,213 had internal pelvimetry. The system and traditional vaginal examination were operated by senior midwives after relevant training to measuring the pelvis. Analyzing the accuracy and correlation of different measuring methods in pelvimetry.[Results]1、The average of external pelvimetry by LP system and traditional pelvic measurements:Interspinal diameter:24.36±1.93cm&24.38±1.42cm(p>0.05), absolute error:1.24±1.14cm; Linear regression analysis:Ytra.=0.39×XLP+14.91 (r=0.528,R2=0.276,p<0.05).External conjugate:20.22±1.94cm&20.18±1.28cm (p>0.05), absolute error:1.42±1.23cm;Linear regression analysis: Ytar=0.25±XLP+15.15(r=0.375,R2=0.137,p<0.05). Intertuberous diameter:9.18+ 0.79cm&8.75±0.41cm(p<0.05), absolute error:0.53±0.51cm; Linear regression analysis:Ytra=0.34×XLp+5.60(r=0.664,R2=0.439,p<0.05); Subsection by 0.5cm, both the proportion and average of absolute error, which greater than or equal to 0.5cm, were maximum in the group of [9.0,9.5)cm:50.96%(53/104)&1.09± 0.48cm(p>0.05); Subsection by parity, only in the data of interspinal diameter by LP system, there’re significant difference between the group of the parity equal to 0 and 3. Furthermore, the error and absolute error of the two methods are significant between the group of parity equal to 3 and 0、1.2, The average of internal pelvimetry by LP system and traditional pelvic measurements:Bi-ischial diameter:9.81±0.96cm&9.69±0.70cm(p<0.05), absolute error:0.37±0.34cm; Linear regression analysis:Ytra.=0.64xXLP+3.44 (r=0.873, R2=0.762,p<0.05); Subsection by 1.0cm, both the proportion and average of absolute error, which greater than or equal to 0.5cm, increased with the increasing bi-ischial diameter(p>0.05). Incisura ischiadica:5.0±1.03cm&4.74±0.81cm(p<0.05), absolute error:0.41±0.43cm; Linear regression analysis:Ytra.=0.67×XLP+1.37 (r=0.860,R2=0.739, p<0.05); Subsection by 1.0cm, both the proportion and average of absolute error, which greater than or equal to 0.5cm, were maximum in the group of [5.0,6.0)cm:50%(41/82)&0.99±0.39cm(p>0.05); Subsection by parity, only the error and absolute error of bi-ischial diameter by the two methods are significant between the group of parity equal to 3 and 0> 1.[Conclusion](1)The parameters of pelvis by LP system are highly correlated with traditional measurement, irrespective of parity;(2) In maternal pelvimetry, LP system is more accurate and objective, which good for selecting delivery methods;(3) Absolute error was maximum when intertuberous diameter in [9.0,9.5)cm and incisura ischiadica in [5.0,6.0)cm, where advantages of LP system more obvious. In pelvimetry, LP system could be the potential alternatives to traditional measuring method;(4) This provides some new research directions for future labor care research, and offer some basis of reducing cesarean section rate to a certain extent.Part 2 Analysis of labor progress by computerized LaborPro system[Purpose]To initially explore the correlation between cervical dilatation(CD) and fetal head station(HS) and their progress, and then ascertain the clinical value of real-time monitoring of labor progress by LP system.[Methods]We select 299 singleton term pregnancies during the active phase of vertex, uncomplicated labor from January 2014 to May at Nanfang Hospital. The LP system were operated by senior midwives after relevant training to measuring cervical dilatation and fetal head station at the same time and repeated over a period of time. Analyzing the changes in values of cervical dilatation and fetal head station and the correlation between them.[Results]1、Comparative analysis of LP system and traditional vaginal measurements of cervical dilatation(1) Error analysis:the average by LP system and traditional vaginal examination:6.27±2.28cm&6.21±2.40cm(p<0.05), absolute error:0.34+0.25cm;(2) Linear regression analysis:Ytra.=1.04×XLP-0.31(r=0.985,R2=0.970, p<0.05);(3) Subsection by 1.0cm:in active labor, both the proportion and average of absolute error, which greater than or equal to 0.5cm, were maximum in the group of (7.0,8.0)cm:45.95%(17/37)&0.86±0.20.2、Comparative analysis of LP system and traditional vaginal measurements of fetal head station(1) Error analysis:the average by LP system and traditional vaginal examination:-0.93±1.60cm&-0.97±1.69cm(p<0.05), absolute error:0.35± 0.27cm;(2) Linear regression analysis:Ytra=1.02×XLP-0.02(r=0.965,R2=0.932, p<0.05);(3) Subsection by 1.0cm:absolute error of (-3,-2)group maximal:0.42± 0.32cm, the proportion of absolute error, which greater than or equal to 0.5cm,were maximum in the group of (-3,-2):39.13% (45/115), the max average of absolute error, which greater than or equal to 0.5cm,0.73±0.31cm in the group of (3,2), whereas there’re no significant difference among the absolute error.3、Conjoint analysis of cervical dilatation and head descent(1) Analysis of the progress of fetal head station, grouped by cervical dilatation:Subsection by 1.0cm:In the group of [7,8)cm, absolute error of cervical dilatation and the proportion of greater than or equal to 0.5cm ones were maximal: 0.44±0.29cm(95%CI:0.34,0.54)&38.24%(13/34);In the group of[6,7)cm, the absolute error of fetal head station and the proportion of greater than or equal to 0.5cm ones were maximal:0.38±0.21cm(95%CI:0.32,0.44)&36.17%(17/47); When the absolute error of cervical dilatation and head descent are both greater than or equal to 0.5cm, proportion was maximal in the group of [6,7)cm. Subsection by parity, only the cervical dilatation in the group of parity equal to 0 and 2 are different significant.(2) Analysis of the progress of cervical dilatation, grouped by fetal head station:Subsection by 1.0:with the progress of fetal head station, absolute error was gradually narrowing; the proportion of greater than or equal to 0.5cm ones were maximal in the group of [-1,0). Absolute error of cervical dilatation and the proportion of greater than or equal to 0.5cm ones was maximal in the group of (0,1): 0.42±0.28 (95%CI:0.34,0.50&44.90%(22/49);When the absolute error of cervical dilatation and head descent are both greater than or equal to 0.5cm, proportion was maximal in the group of<3 and[-1,1). Subsection by parity, the head descent in all group are undifferent significant.(3)Conjoint analysis of cervical dilatation and head descent:When cervical dilatation reached 6cm (corresponding average of fetal head station:-0.50±0.61), descending of fetal head decreased significantly, especially the segment of 8-10cm. Linear regression analysis:YHS=0.57XCD-3.93 (r=0.867,R2=0.751,p<0.05); When fetal head station reached -2 (corresponding average of cervical dilatation:4.50±1.11cm, cervical dilatation progressed significantly, especially the segment of -2-0cm. Linear regression analysis: Ycd=1.33Xhs+6.76 (r=0.867,R2=0.751,P<0.05); In the first stage of labor, multiparous women tend to have a higher station than nulliparous ones.[Conclusion](1) Compared with traditional measurement, the parameters of cervical dilation and fetal head station by LP system are better. LP system could be the potential alternatives to traditional digital assessment.(2) Absolute error was maximum when cervical dilatation in [6,7)cm and head descent in [-1,1)cm, where advantages of LP system more obvious. In labour monitoring, LP system could be a objective method.(3) There’s a certain highly positive correlation between the two labor monitoring indicators.(4) In the same group of cervical dilation or fetal head station, there’re no significant difference between primiparae and multipara.The study, which focuses on the correlation between cervical dilatation and fetal head station, the evaluating value in labor monitoring, drawing neotype partogram and the reformation diagnostic criteria of abnormal labor, would benefits reducing the high rate of cesarean section, guaranteeing safety of mother and fetus and improving the obstetric quality.