Head circumference, as predictor of cephalopelvic disproportion: A prospective analysis of cases of spontaneous vaginal delivery and caesarean section in Ekiti State, Nigeria

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%.