Frequently Asked Questions
Using the tool
Is Fetal Growth Chart free?
Yes. The tool is free to use. The site is supported by advertising, and ads are never shown on the printed report.
Do I need to create an account?
No. There is no login, no account and no patient database. Open the Growth Chart and start entering measurements.
Where is my data stored?
Only in the browser tab you are using. Nothing is sent to a server, Google Sheets or Google Drive, and nothing is saved in the browser's persistent storage. When you close or refresh the tab, the measurements are cleared. The browser will warn you before you leave the page with unsaved measurements.
Why can't I enter the patient's name?
So that no patient-identifying information ever goes into a public website. The printed report has blank Name, ID and Clinic boxes for you to fill in by hand before filing.
How many measurements can I plot?
Up to five per pregnancy. This keeps the printed report on one A4 page for singletons (two pages for twins) with readable charts.
I made a mistake in a measurement. Do I have to start again?
No. Each row in the Measurement History has Edit and Delete buttons. Edit loads the values back into the form. Change them and press Update.
Why does the tool warn me before saving?
It checks for common entry errors: a value far outside the expected range for that gestation (often a unit error, such as cm instead of mm), a repeated POG, or dates and POG that do not match between visits. You can still save if the value is correct.
Does the tool calculate EFW?
No. Enter the EFW reported by your ultrasound machine. The tool plots it against the WHO EFW centiles. See Estimated fetal weight for how EFW is calculated.
Does it work on a phone?
Yes. The layout and charts adjust to the screen size. For printing, a computer is easier.
The print window does not open.
The report opens in a new window. If nothing happens, your browser has probably blocked pop-ups. Allow pop-ups for fetalgrowthchart.com and press Print again.
Interpreting the charts
Which centiles are shown?
The 5th, 25th, 50th, 75th and 95th WHO centiles. The history table also labels each value with its centile band, such as "25–50th". See How to read a fetal growth chart.
Why are there no 3rd or 10th centile lines?
The tool currently draws five centile lines. The 3rd and 10th centiles used in some FGR definitions are not drawn, so use your unit's reference for those thresholds.
What gestational ages are covered?
The WHO reference covers 14 to 40 weeks. The chart axis runs from 13 to 41 weeks. Centile bands are only shown for values between 14 and 40 weeks.
Can I use the WHO charts for twins?
The tool plots each twin against the WHO reference, which was derived from singletons. Whether singleton or twin-specific charts should be used is debated. Follow your unit's protocol. See Twin growth assessment.
My machine's centile is different from this chart.
Your ultrasound machine probably uses a different reference (for example Hadlock or INTERGROWTH-21st). Different references give different centiles for the same value. See About the WHO charts.
Is this an official WHO application?
No. It is an independent implementation of the published WHO reference. See the Disclaimer.
Can patients use this tool?
The tool is designed for healthcare professionals. Growth charts need clinical interpretation together with the full clinical picture. Pregnant women with questions about their scan should discuss them with their doctor or midwife.