Birth weight prediction from remote ultrasonographic examination.

Multiple linear regression by the least squares method was used to remodel five existing static equations to permit birth weight estimates from remote ultrasonographic parameters. By incorporating lapse time (examination-to-delivery interval), the new equations can be used to estimate birth weight 0 to 35 days after ultrasonographic examination. For each model, R2 approached 1.0. The generated equations were tested on 167 nonmodel cases. Among the three best equations, 65% to 67% of estimates were within 100 mg/kg birth weight. The mean absolute error ranged from 86 to 91 gm/kg. With a mean lapse time of 16.8 +/- 11 days, the accuracy of birth weight estimates equaled or exceeded that reported for existing static formulas. The accuracy of the estimates was maintained across the entire range of lapse times and birth weights observed. In intrapartum situations when ultrasonography is unavailable or technically difficult, birth weight can be estimated from remote ultrasound parameters.