Infantometer

An infantometer is a device used to measure the recumbent length of infants and young children who cannot stand independently. It consists of a rigid, flat measuring board with a fixed headboard and a movable footboard or sliding footpiece, along with a calibrated measurement scale typically in centimeters (and sometimes inches). The instrument is used in pediatric clinics, hospitals, and research settings to obtain an accurate length for growth assessment and to classify growth according to standards such as the WHO Child Growth Standards.

Design and use: The infant lies on the back on the board with the head flush against the headboard. The spine is kept straight and the head is aligned so the Frankfort plane is approximately horizontal. The footboard is then moved until the soles touch while the infant remains still. Length is read from the scale to the nearest 0.1 cm or 1 mm. Some devices include digital readouts or integrated scales.

Procedure considerations: Measurements are typically taken with minimal clothing and a diaper adjusted as needed. The examiner ensures the infant is calm and still; multiple measurements may be taken to improve reliability, with the average used for reporting. Standard protocols from pediatric growth assessment guidelines are often followed.

Accuracy and limitations: Potential sources of error include infant movement, improper alignment, diaper thickness, or incorrect knee/hip position. Proper training and regular calibration of the instrument help minimize error. Recumbent length measurements are preferred for infants up to about 24 months, after which standing height is used when possible.