Variation of Prenatal Ultrasound-Estimated Cephalic Index; A Comparative Study of Igbo, Hausa and Yoruba Ethnic Groups in Nigeria

Background: Fetal ultrasound-estimated cephalic index refers to the ratio of the fetal biparietal diameter (BPD) to the occipito-frontal diameter (OFD) by means of ultrasound estimation. The cephalic index is regarded as a useful anthropometric variable in medicine, forensic science and anthropology. There is limited data on the cephalic indices of Nigerian fetuses Objective:  To check for variations of prenatal ultrasound-estimated cephalic indices between fetuses of Igbo, Yoruba and Hausa ancestry. Methodology: In a cross sectional study carried out in ultrasound diagnostic centres in Lagos, Enugu and Kano, all in Nigeria, fetal biparietal and occipitofrontal diameters were obtained from 200 fetuses each of Igbo, Yoruba and Hausa ethnic groups. The cephalic index was calculated for each group. The values were statistically analysed after deriving the relevant indices. Result: The fetal cephalic indices for  Igbo, Yoruba and Hausa ethnic groups were observed to be 80 ± 3.4, 79.1 ± 5.1 and 78.4 ± 2.6 %,  respectively. Conclusion:  The results showed that fetuses of Igbo ancestry had a different cephalic index categorization from other ethnic groups. This knowledge will be useful to sonographers and researchers.