In vitro myometrial contractility profiles of different pharmacological agents used for induction of labor.
OBJECTIVE
To investigate the effects of different pharmacological induction agents on myometrial contractility.


METHODS
Myometrial biopsies were obtained from 13 term nonlaboring women undergoing scheduled cesarean delivery. Tissue strips were suspended in organ chambers for isometric tension recording. The effects of cumulative doses (10-10 mol/L to 10-5 mol/L) of prostaglandin E1 (PGE1), E2 (PGE2), and oxytocin on spontaneous uterine contractility were determined. Areas under the contraction curve were compared using one-way analysis of variance on ranks with Dunn post hoc test.


RESULTS
Oxytocin-induced myometrial contractility was superior to PGE1, PGE2, and time controls (CTR) at all the concentrations tested. When only prostaglandins were compared with CTR, PGE1 10-5 mol/L increased myometrial contractility, and PGE2 had no effects.


CONCLUSIONS
Oxytocin and prostaglandins have different effects on myometrial contractility accounting for different mechanisms of action and side effects. The increased uterine contractility observed with PGE1 as compared with PGE2 can contribute to explain the higher success of vaginal delivery.
Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555-0144, USA. gichioss@utmb.edu
Giuseppe
G
Chioss
Maged M
MM
Costantine
Egle
E
Bytautiene
Ancizar
A
Betancourt
Gary D V
GD
Hankins
George R
GR
Saade
Monica
M
Longo
D000328:Adult; D000527:Alprostadil / Q000494:pharmacology*; D000704:Analysis of Variance; D001706:Biopsy; D015232:Dinoprostone / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects*; D007751:Labor, Induced / Q000379:methods; D009215:Myometrium / Q000473:pathology*; D010120:Oxytocics / Q000494:pharmacology*; D010121:Oxytocin / Q000494:pharmacology*; D011247:Pregnancy
D010120:Oxytocics; D010121:Oxytocin; D000527:Alprostadil; D015232:Dinoprostone