Possible circadian periodicity of foetal prolactin secretion late in gestation
Yaginuma, T.
Acta Endocrinologica 98(1): 106-111
1981
ISSN/ISBN: 0001-5598 PMID: 7282263 Document Number: 173974
Prolactin levels were determined in samples of umbilical venous blood at vaginal delivery after 38-42 wk of uncomplicated gestation. The mean level of prolactin for all samples was 328.4 .+-. 7.4 (SE) ng/ml. The levels did not vary significantly during these weeks of gestation, nor correlate with the duration of labor. The means of levels combined every 2 h varied significantly throughout the 24 h period with a maximum value of 460.3 .+-. 85.1 ng/ml at 0200 h-0400 h and a minimum value of 241.4 .+-. 27.2 ng/ml at 0600 h-0800 h and remained relatively constant between 1400 h-1600 h and 2200 h-2400 h. A circadian periodicity may exist in the secretion of prolactin by the human fetus, and this is not affected by labor and delivery.