[Measurement of the motor nerve conduction rate: a precise method of assessing newborn maturity? (author transl)].

During the period 1.10.1979 to 31.1.1981 508 maturity determinations were carried out in 483 infants at the Department of Medical Obstetrics of the Neukölln Hospital in Berlin, using the motor nerve conduction rate of the n. ulnaris in combination with the FARR schema. The median value of the NCR increases from 13.0 m/sec in the 33rd pregnancy week (PW) to 30.4 m/sec in the 44th PW almost in linear progression by 1.58 m/sec per week. Over the entire range the NCR showed a highly significant correlation (r = 0.946 at p greater than 0.00001) with the gestatory age of the infant, whereas the FARR schema differs up to the 38th PW markedly in false-positive direction. Measurement of the motor NCR of the n. ulnaris is evidently a simple and very accurate method for post-partum determination of the gestatory age.