title: Effects of labor contractions on catecholamine release and breathing frequency in newborn rats.
abstract: Plasma catecholamines in newborn rats (0-2 hr old) were analyzed following vaginal birth, cesarean section with simulated labor contractions, or cesarean section without labor contractions. Upon delivery, pups were exposed to key elements of the rat's natural birth process, that is, umbilical cord occlusion, tactile stimulation, and cooling. Only pups exposed to actual or simulated labor showed an immediate rise in norepinephrine and epinephrine. Initial postpartum respiratory frequencies were higher in vaginal than in cesarean delivered pups and, in all groups, inversely correlated with catecholamine titers, suggesting respiratory distress or transient tachypnea at lower catecholamine levels. These findings establish a rat model for analyzing effects of labor on neonatal adaptive response during the transition from prenatal to postnatal life.
authors.affiliation: Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston Salem, NC 27157, USA. aronca@wfubmc.edu
authors.forename: April E
authors.initials: AE
authors.lastname: Ronca
authors.forename: Regina A
authors.initials: RA
authors.lastname: Abel
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Ronan
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Renner
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Alberts
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn / Q000097:blood*; D002395:Catecholamines / Q000097:blood*; D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D008297:Male; D011247:Pregnancy; D051381:Rats; D012119:Respiration; D013997:Time Factors
chemical_list: D002395:Catecholamines