US EPA

6967373 

Journal Article 

Parturition 

Gibb, W; Lye, SJ; Challis, JRG; , 

2006 

ELSEVIER ACADEMIC PRESS INC 

SAN DIEGO 

KNOBIL AND NEILL'S PHYSIOLOGY OF REPRODUCTION, VOLS 1 AND 2, 3RD EDITON 

2925-2974 

WOS:000311804003005 

Preterm labor is one of the major problems in obstetrics and its incidence has not decreased since the mid-1980s. There have, however, been considerable advances in our understanding of the mechanisms involved in parturition. The onset of parturition is controlled by endocrine, inflammatory, and mechanical factors. Maturation of the fetal hypothalamic-pituitary-adrenal axis and stretch of the uterus due to growth of the fetus regulate the expression of various genes involved in parturition. During most of pregnancy the myometrium is relatively quiescent, and contractions that do occur are poorly coordinated. Near term, the myometrium becomes responsive to substances that stimulate strong contractions (uterotonins). Many of these uterotonins are synthesized in the uterine tissues. The factors involved in maintaining uterine quiescence during pregnancy are discussed, as is the regulation of the synthesis of contraction-associated proteins that enable the myometrium to contract. The regulation of the synthesis of various uterotonins, including prostaglandins and oxytocin, and the mechanisms involved in cervical ripening and membrane rupture, are reviewed. Regulation of parturition is multifactorial, and when the appropriate expression of contraction-associated proteins and uterotonins occurs, normal labor will ensue. The review discusses studies using various experimental animals, including sheep, rodents, and nonhuman primates, and attempts to relate the findings to studies that have been carried out in human pregnancy. 

Neill, JD; 

978-0-12-515400-0