Early type of pelvimeter with curved blades, sliding and fixed scales and ebony handle, by Sirhenry, Paris, circa 1800

French instrument maker Sirhenry of Paris made this early pelvimeter. It measured the pelvic diameters of pregnant women. The opening of the handles allowed measurements to be read off a sliding scale. This was part of a scientific attempt to identify those women most likely to experience obstructed labour. The technique was called pelvimetry. It was developed during the late 1700s by Frenchman Jean Louis Baudelocque (1746-1810).