A microcomputer program was developed to compute the expected date of confinement (EDC) and to record the clinical parameters used in its calculation. In obstetrical care, it is important to establish the EDC. However, the last menstrual period on which the EDC is usually determined may be unknown, inaccurate or disagree with other clinical estimators of the gestational age. Useful predictions of the EDC can be derived from a number of clinical examinations. The program can be used to maintain a register from which the EDC is calculated by averaging the EDCs estimated from up to 19 parameters. The result is also displayed as the gestation age in number of weeks. The register containing information on a large number of pregnancies can be used to calculate the dispersion of estimated EDCs from the various clinical methods.