Fetal ultrasound biometry: 1. Head reference values.
- Kurmanavicius J Department of Obstetrics, Zurich University Hospital, Switzerland.
- Wright EM
- Royston P
- Wisser J
- Huch R
- Huch A
- Zimmermann R
- 1999-07-30
Published in:
- British journal of obstetrics and gynaecology. - 1999
Adult
Cephalometry
Cross-Sectional Studies
Female
Gestational Age
Head
Humans
Pregnancy
Prospective Studies
Reference Values
Ultrasonography, Prenatal
English
OBJECTIVE
To create reliable reference ranges and calculate Z scores for fetal head ultrasound biometry using a large sample size which is evenly distributed from 12 to 42 weeks of pregnancy.
DESIGN
A prospective, cross-sectional study.
SETTING
Obstetric clinics (outpatient and delivery units) at the University Hospital of Zurich.
SAMPLE
The study data were obtained from 6557 pregnant women.
METHODS
Only the first ultrasound examination between 12 and 42 weeks of each fetus with exactly established gestational age was used for analysis. No exclusions were made on the grounds of small-for-date birthweight, prematurity or other events several weeks after the examination. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each parameter.
RESULTS
A total of 6217 fetal head biparietal diameters and 5510 occipito-frontal diameters were measured. Both head circumference and cephalic index were derived in 5462 cases where both biparietal diameter and occipito-frontal diameter could be measured on the same fetus. The centile charts, tables and regression formulae for biparietal and occipito-frontal diameters, head circumference and cephalic index are presented. An application to calculate Z scores was developed using Excel (Microsoft Corporation, USA) and macros are presented in detail in the Figure 8 footnote. The comparison of our charts with those of the two most recent studies revealed almost no differences in biparietal diameter centiles. In one publication, occipito-frontal diameter charts, and in another, head circumference charts were different from the current study.
CONCLUSIONS
We have presented centile charts, tables and regression formulae for fetal head ultrasound biometry derived from a large and minimally selected sample size in a carefully designed cross-sectional study. Complete tables and regression formulae to calculate reference ranges and Z scores are presented for use in computer-aided evaluation of fetal ultrasound biometry.
To create reliable reference ranges and calculate Z scores for fetal head ultrasound biometry using a large sample size which is evenly distributed from 12 to 42 weeks of pregnancy.
DESIGN
A prospective, cross-sectional study.
SETTING
Obstetric clinics (outpatient and delivery units) at the University Hospital of Zurich.
SAMPLE
The study data were obtained from 6557 pregnant women.
METHODS
Only the first ultrasound examination between 12 and 42 weeks of each fetus with exactly established gestational age was used for analysis. No exclusions were made on the grounds of small-for-date birthweight, prematurity or other events several weeks after the examination. Separate regression models were fitted to estimate the mean and standard deviation at each gestational age for each parameter.
RESULTS
A total of 6217 fetal head biparietal diameters and 5510 occipito-frontal diameters were measured. Both head circumference and cephalic index were derived in 5462 cases where both biparietal diameter and occipito-frontal diameter could be measured on the same fetus. The centile charts, tables and regression formulae for biparietal and occipito-frontal diameters, head circumference and cephalic index are presented. An application to calculate Z scores was developed using Excel (Microsoft Corporation, USA) and macros are presented in detail in the Figure 8 footnote. The comparison of our charts with those of the two most recent studies revealed almost no differences in biparietal diameter centiles. In one publication, occipito-frontal diameter charts, and in another, head circumference charts were different from the current study.
CONCLUSIONS
We have presented centile charts, tables and regression formulae for fetal head ultrasound biometry derived from a large and minimally selected sample size in a carefully designed cross-sectional study. Complete tables and regression formulae to calculate reference ranges and Z scores are presented for use in computer-aided evaluation of fetal ultrasound biometry.
- Language
-
- English
- Open access status
- bronze
- Identifiers
-
- DOI 10.1111/j.1471-0528.1999.tb08212.x
- PMID 10426678
- Persistent URL
- https://sonar.ch/global/documents/122214
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