Gestational age assessment. II. Prediction from combined clinical observations.

Accurate assessment of the estimated date of confinement is a cornerstone of obstetric care. In an earlier report, we examined the time of occurrence of various historical and clinical estimators of gestational age in relation to the date of delivery. We now examine the possibility of combining multiple clinical estimators to improve the prediction of delivery date. Formulas for predicting delivery date from multiple clinical estimators were developed in a group of 418 patients who were delivered of infants weighing greater than or equal to 3,000 gm, after spontaneous onset of labor. These formulas were tested in a separate group of 107 patients who fulfilled similar criteria. In patients with a known last menstrual period, additional clinical information did not improve the prediction of delivery date; however, if the last menstrual period was uncertain or unknown, averaging the predicted delivery dates by several clinical examinations provided a prediction of delivery date as precise as if the last menstrual period were known.