Abstract：
Cephalopelvic disproportion (CPD) is a previously undiagnosed anatomical misfit between maternal pelvis and the fetal head. It is one of the major indications for cesarean section (CS), especially in sub-Saharan Africa. Early diagnosis, could avert events that can increase maternal and perinatal morbidity and mortality associated with this condition. This study was designed to determine the mean head circumference of the fetus in relation to CPD as an indicator for caesarean section. A total of 350 parturients who had spontaneous vaginal deliveries (group A) were compared with another 350 parturients who had cephalopelvic disproportion leading to CS (group B). The socio-demographic characteristics, delivery parameters, head circumference, fetal weight and length were recorded in a proforma and analyzed using SPSS version 21. P value was set at 0.05. The mean head circumference for the all the babies delivered in this study was 34.6 ±1.7cm. The mean head circumference of babies delivered to women with CPD via caeserean section compared to those who had vaginal delivery was significantly greater (35.15±1.5 vs 34.1±1.8, mean difference 1.9±0.1, X2,0.308 p <0.001). The cut-off for diagnosis of cephalopelvic disproportion was head circumference 34.8cm which has a specificity of about 74% and sensitivity of 88% with area under the curve being 66%. The study demonstrated that when the head circumference of a baby is 34.8cm and above, the risk of having cephalopelvic disproportion leading to a CS is high with sensitivity of 88% and specificity of about 74%.
摘要：
头颅骨盆比例失调（CPD）是先前未诊断的母体骨盆和胎儿头部之间的解剖学失调。它是剖宫产（CS）的主要指征之一，尤其是在撒哈拉以南非洲。早期诊断,可以避免可能增加与这种情况相关的孕产妇和围产期发病率和死亡率的事件。这项研究旨在确定与CPD相关的胎儿平均头围，以作为剖宫产的指标。将总共350例自发阴道分娩的产妇（A组）与另外350例头骨盆不相称导致CS的产妇（B组）进行了比较。社会人口特征，交货参数，头围,以形式记录胎儿体重和身长,并使用SPSS版本21进行分析.P值设定为0.05。在这项研究中分娩的所有婴儿的平均头围为34.6±1.7厘米。与经阴道分娩的妇女相比，通过剖腹产分娩给CPD妇女的婴儿的平均头围明显更大（35.15±1.5vs34.1±1.8，平均差1.9±0.1，X2,0.308p<0.001）。头盆比例失调的诊断界限是头围34.8cm，其特异性约为74％，敏感性为88％，曲线下面积为66％。研究表明，当婴儿的头围在34.8厘米及以上时，导致CS的头端肾盂比例失调的风险很高，敏感性为88％，特异性约为74％。
