It's usually sometime in elementary school when students first learn about standard international units and the historical origin of the foot-measure. As the story goes, landowners and laborers alike required a standard measure, and King Henry III's foot seemed a plausible enough option. This solution arose from centuries of use of a convenient, body-based metric readily available in the field.
Today, maternal health researchers have found the age-old metric to hold new relevance: studies in recent years support a positive correlation between newborn foot length and low birth weight. Measuring infants’ feet in rural, low-income regions where most children are born at home presents the opportunity to improve neonatal mortality rates on a significant scale. This simple measure will equip midwives, community members, and parents alike with the ability to screen infants born prematurely or underweight out in the field, and target them to receive the necessary medical attention they need to survive.
Studies in countries ranging from Tanzania and Uganda to India, Nepal, and Iran have rigorously tested this measure against other body-based indicators on infants in the few days after birth. While most studies maintain that measuring around a newborn’s chest, for instance, [more accurately identifies low birth weight]( http://www.ncbi.nlm.nih.gov/pubmed/16885929), measuring an infant’s foot length is still [quite accurate and much more efficient]( http://www.biomedcentral.com/1471-2458/10/624/figure/F1?highres=y:). Laying a ruler against a newborn’s foot rather than looping a tape around her torso circumvents the time-consuming and warmth-robbing process of removing clothing, as well as the extra training necessary to correctly take the measurement.
Out in the field where the problem of identifying low birth weight infants is most rampant, this efficiency is of paramount importance. Researcher [Tanya Marchant and her team]( http://www.biomedcentral.com/1471-2458/10/624) write that, “over half of all babies born in sub-Saharan Africa for example are born at home and the majority of communities and families have no access to scales or other means by which to identify a baby as small, at risk, and in need of extra care.” [Nejar Sajjadian’s team bolsters this research]( http://www.scirp.org/journal/PaperInformation.aspx?paperID=9047), and the importance of identifying LBW infants in the first week of life, citing more statistics from their study in Iran:
"An estimated 18 million babies are born with LBW. They account for 60%-80% of neonatal deaths. Moreover, LBW who survive the critical neonatal period may suffer impaired physical and mental growth. Therefore, an early identification and prompt referral of LBW newborns is vital in preventing neonatal deaths."
To this end, researchers have begun developing special foot-length measuring tools. [SS Hirve’s team]( http://www.ncbi.nlm.nih.gov/pubmed/8406702) created a “tri-colored foot tape intended for use at home by the neonatal caretaker or birth attendant.” As we went to publish this blog we came across a [Healthy Newborn Network blog post by Tanya Marchant which further describes the tool](http://www.healthynewbornnetwork.org/blog/measuring-newborn-foot-length-small-step-forward).
A standardized tool has not yet been put into production, but innovators with a penchant for design, utility in the field (and perhaps the [complex history of kings and their feet](http://en.wikipedia.org/wiki/Foot_(unit))) may well bring neonatal health a few steps forward by rebranding the foot measure.