1985 Volume 32 Issue 2 Pages 121-126
The non-stress test (NST), a measure of normal fetal movement and accompanying acceleration, is a useful method of perinatal fetal evaluation. The fetal movement and spontaneous onset of fetal acceleration observed in normal fetus suggests a coordinated control of both these functions, presumably arising in the fetal central nervous system (CNS). Since the developmental features of the regulation mechanism of fetal heart rate and fetal movement by the fetal brain in mid trimester are not known, interpretation would be rather speculative. The present prospective study was designed to evaluate the landmarks of normal fetal development in mid trimester by NST. The study revealed the following: 1) Maternal perception of fetal movements were closely associated with trunk movements observed to last for 1 second or longer by real-time B-scanning. 2) The ratio of fetal movement to total accelerations increased with the progression of pregnancy during 20 to 32 weeks' gestation. 3) The majority of accelerations in fetal heart rate had amplitudes within the range of 10-15 bpm before the 30th weeks' gestation and 15 bpm or greater at or after the 30th weeks' gestation.
