A computer system was developed to predict congestion of the obstetric ward in the near future. The admittance and stay in the obstetric ward of every registered patient are simulated based on the table of reservation and observed data of hospital stay, and from this the number of inpatients (occupied beds) is predicted. If the expected date of confinement of every obstetric patient is put into the computer and the information on patients who have already given birth is deleted, it is possible to obtain a reasonably accurate prediction.