The Roussel Pregnancy Calculator

New York, New York: Roussel Corporation, 1968. Very good.. An advertising volvelle for "Pro-Duosterone", an oral pregnancy test marketed as effective two weeks earlier than other biologic tests. A course of four tablets per day for three days is taken. If nothing happens, the patient is pregnant; if the patient is not pregnant, menses will begin. To use the volvelle, the first day of the last menstrual period is aligned with the outer calendar; then, the EDC ("estimated date of confinement") can be predicted plus or minus five days. Volvelle measures 5" by 5", with inner circle measuring 3.75" in diameter, held together by a small metal grommet.