|
1. Study design
|
| 1.1 Design |
Clearly described as either cross-sectional or longitudinal |
Not reported, mixture of both |
| 1.2 Sample selection |
Population-based study where there are attempts to identify and clearly define populations from a specific geographical area; from this underlying population, women are selected either consecutively or at random |
Not population based; convenience sampling; arbitrary recruitment; or not reported |
| 1.3 Number of occasions each fetus was measured (only for cross-sectional studies) |
Each fetus was measured and included only once |
Some fetuses were measured and included more than once |
| 1.4 Method of selecting the gestational ages at which the fetuses were measured (only for longitudinal studies) |
Interval of measures prospectively prespecified and justified |
Interval of measures not prospectively prespecified and justified or not reported |
| 1.5 Reason(s) for choosing a particular number of serial measurements (only for longitudinal studies) |
Clear documentation of the intended number of serial measurements |
No clear documentation of the intended number of serial measurements |
| 1.6 Inclusion/exclusion criteria |
The study made it clear that women at high risk of pregnancy complications were not included, and that women with abnormal outcome were excluded, i.e. an effort was made to include ‘normal’ outcome as best possible |
The study population included both low-risk and high-risk pregnancies, or women with abnormal outcome were not excluded. Study population that did not exclude fetuses or women with the characteristics previously described. Exclusions which would have a direct effect on the estimated percentiles, such as fetuses found at birth to be large or small for dates. |
| 1.7 Sample size |
A priori determination/calculation of sample size and justification |
Lack of a priori sample size determination/ calculation and justification |
| 1.8 Data collection |
Prospective study and ultrasound data collected specifically for the purpose of constructing charts of fetal size or fetal growth |
Retrospective study, or data not collected specifically for the purpose of constructing charts of fetal size or fetal growth, or unclear (e.g. use of routinely collected data) |
| 1.9 Method of dating pregnancy |
Clearly describedKnown last menstrual period (LMP) and regular menstrual cycles prior to pregnancy AND a sonogram before 14 weeks demonstrating a crown–rump length (CRL) that corroborates. |
Gestational age assessment at > 14 weeks, or gestational age assessment not including ultrasonographic verification |
| 1.10 Collection of data on gestational age at inclusion |
The gestational age was calculated precisely to the day |
Truncation of gestational age to the number of ‘completed weeks’ |
|
2. Statistical methods
|
| 2.1 Number of measurements taken for each biometric variable |
More than one measure per fetus per scan |
Single measure or not specified |
| 2.2 Statistical methods |
Clearly described and identified |
Not clearly described and identified |
| 2.3 Assessment of increasing variability of the data with gestation |
Performed |
Not performed |
| 2.4 Assessment of goodness of fit of the models |
A test of goodness of fit of the models was reported |
Goodness of fit of models was not reported |
| 2.5 Scatter diagram of the data with the fitted percentiles superimposed |
Study included scatter diagrams of the data with the percentiles superimposed |
Study did not include scatter diagrams of the data with the percentiles superimposed |
| 2.6 Change in reference percentiles across gestational age |
Smooth change |
Not smooth change |
| 2.7 Methods used to estimate age specific reference intervals for fetal size measurements |
Mean and standard deviation (SD) model', smoothed crude percentiles, or ‘LMS method |
Inadequate |
|
3. Reporting methods
|
| 3.1 Characteristics of study population |
Presented in a table or clearly described, and includes minimum dataset of age, weight, height or body mass index and parity |
Not presented in a table or not clearly described, or does not contain minimum dataset |
| 3.2 Description of number approached/ enrolled |
Described |
Not described |
| 3.3 Ultrasound machine(s) used |
Clearly specified |
Not clearly specified |
| 3.4 Number of sonographers that took the measurements |
Reported |
Not reported |
| 3.5 Description of measurementtechniques |
The study described sufficient and unambiguous details of the measurement techniques used for fetal size parameters, including imaging plane and caliper application method |
The study did not describe sufficient and unambiguous details of the measurement techniques used for fetal size parameters |
| 3.6 Contains quality control measures |
Should include the following:– assessment of intraobserver variability– assessment of interobserver variability– image review– image scoring– image storage |
Does not contain quality control measures |
| 3.7 Report of mean and SD of eachmeasurement and the sample size for each week of gestation |
Presented in a table or clearly described |
Not presented in a table or not clearly described |
| 3.8 Report of regression equations for the mean (and SD if relevant) for each measurement |
Reported |
Not reported |
Thumbnail
