title: Nicotine treatment prolongs gestation and inhibits cervical ripening in pregnant rats.
abstract: OBJECTIVE
  The aims of this study were to examine the effects of nicotine treatment on the length of gestation, on fetal outcome, on cervical ripening, and on uterine contractility during pregnancy in rats.
  
  
  METHODS
  Pregnant rats were treated with various concentrations of nicotine (0.25, 0.5, 1, 2 mg/kg/d, subcutaneously). Delivery times and fetal weights were obtained. Cervical collagen cross-links were assessed in vivo by collagen light-induced fluorescence (LIF), and cervical resistance to stretch was measured by in vitro extensibility tests.
  
  
  RESULTS
  Delivery time is significantly (P = .002) prolonged after high-dose nicotine treatments. There are no significant changes in pup weights and placenta weights after nicotine treatments. Cervical collagen LIF and extensibility progressively decrease throughout pregnancy in control rats. Nicotine-treated rats showed significant (P < .001) cervical resistance to stretch and higher LIF compared with the control rats. Nicotine treatment in vitro had little effect on uterine contractility.
  
  
  CONCLUSIONS
  Nicotine exposure during pregnancy prolongs gestation and inhibits cervical ripening, possibly by suppression of a cholinergic antiinflammatory response.
authors.affiliation: Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center and Guangzhou Medical College, Guangzhou, China; St. Joseph's Hospital and Medical Center, Phoenix, AZ.
authors.forename: Jinying
authors.initials: J
authors.lastname: Yang
authors.affiliation: St. Joseph's Hospital and Medical Center, Phoenix, AZ.
authors.forename: Shao-Qing
authors.initials: SQ
authors.lastname: Shi
authors.affiliation: St. Joseph's Hospital and Medical Center, Phoenix, AZ.
authors.forename: Leili
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center and Guangzhou Medical College, Guangzhou, China.
authors.forename: Huishu
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Obstetrics and Gynecology, Guangzhou Women and Children's Medical Center and Guangzhou Medical College, Guangzhou, China; St. Joseph's Hospital and Medical Center, Phoenix, AZ.
authors.forename: Dajun
authors.initials: D
authors.lastname: Fang
authors.affiliation: St. Joseph's Hospital and Medical Center, Phoenix, AZ. Electronic address: robert.garfield@chw.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Garfield
mesh_terms: D000818:Animals; D020070:Cervical Ripening / Q000187:drug effects*; D002584:Cervix Uteri / Q000187:drug effects* / Q000502:physiology; D003094:Collagen / Q000378:metabolism*; D005260:Female; D009538:Nicotine / Q000494:pharmacology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D051381:Rats; D017207:Rats, Sprague-Dawley; D014590:Uterine Contraction / Q000187:drug effects* / Q000502:physiology
chemical_list: D009538:Nicotine; D003094:Collagen
keywords: cervical ripening; collagen cross-links; fetal outcome; inflammation; nicotine; pregnancy; smoking