Charts of fetal size: 2. Head measurements*

Abstract

Objective To construct new size charts for fetal head circumference, biparietal diameter and other head dimensions. Design A prospective, cross sectional study. Setting The routine ultrasound department of a London teaching hospital. Subjects The fetuses of 663 women seen in the routine antenatal booking clinic whose ultrasound and menstrual dates agreed within 10 days. Methods Fetuses were scanned once only for the purpose of the study at gestations between 12 and 42 weeks, when up to 20 dimensions were measured. For each measurement separate regression models were fitted to estimate the mean and standard deviation at each gestational age. Centiles were derived by combining these two regression models, assuming that the measurements have a normal distribution at each gestational age. Results A total of 594 fetuses had their biparietal diameter measured and their head circumference measured directly. Both head diameters were recorded for 587 fetuses and the circumference was also derived from these, as was the cephalic area. New charts are presented for biparietal diameter (both outer–outer and outer–inner), head circumference (directly measured and derived from diameters). The directly measured head circumferences were consistently (by about 1%) greater than those derived from measurement of the head diameters. The new charts are compared with previously published charts that are in wide use. Charts for occipitofrontal diameter, cephalic index and cephalic area are also presented. Conclusions We have constructed new size charts for the fetal biparietal diameter and for head circumference, both measured directly and derived from head diameters. We have demonstrated the difference between the size charts constructed from these two sets of values and hence the importance of using the appropriately derived chart when assessing the head circumference. The differences between the new charts for biparietal diameter and head circumference and previous ones may be largely due to methodological differences.

Sonographic fetal biometry charts for a Pakistani cohort

“…The linear growth of BPD and HC until 34 weeks of pregnancy and the charts derived in this study for the 50th centiles of BPD and HC showed a close agreement with published charts from other countries and another Pakistani cohort [14,17,18]. Continuous linear growth of AC was seen from 16 weeks to the end of pregnancy.…”

“…While growth measurement centiles have been generated by various investigators using standard parameters [11][12][13][14][15][16], almost all fetal biometric growth centiles using sonographic anthropometric measurements have been derived from data from European and American populations [11][12][13][14][15]17]; only a few studies have used Asian women [16,18]. Fetal anthropometric data from the population in Pakistan are limited [18] and fetal centiles derived from other ethnic populations applied in our locality might lead to systematic errors in estimation.…”

Effects of a dairy product fortified with multiple micronutrients and omega-3 fatty acids on birth weight and gestation duration in pregnant Chilean women

“…In pregnancies less than 13 weeks and 6 days, we used crown-rump length and Robinson's chart 15 . Between 14 and 20 weeks, we used biparietal diameter and head circumference and the charts of Chitty 16 . Trained ultrasonographers at each of the two maternity hospitals of the Southeast Metropolitan Public Health Service performed the scans.…”

Impaired uteroplacental blood flow in pregnancies complicated by falciparum malaria

“…Ultrasound-derived gestational age assessment was used when menstrual dates were unknown (n = 310, 31%) or when measurement of fetal size fell more than 2 SD above or below the mean for gestation calculated from menstrual history (n = 220, 22%). Gestational age was calculated from the charts of Chitty et al 15,16 .…”