title: Direct electrical stimulation softens the cervix in pregnant and nonpregnant rats.
abstract: OBJECTIVE
  The objective of the study was to determine the effects of electrical stimulation (ES) on cervical ripening in pregnant and nonpregnant rats.
  
  
  METHODS
  Timed pregnant and nonpregnant Sprague-Dawley rats (n = 6-7/group) were used. Cervical ES for pregnant rats was performed in vivo on day 15 of gestation by inserting an electrical probe into the vagina in contact with the cervix. Parameters of ES varied from 0.1 to 0.2 mA, 10 pulses per second, 20 milliseconds pulse duration, and repeating pulses for 15, 30, 60, and 120 minutes for pregnant ES groups and similar times for sham control groups with electrode but without ES. Nonpregnant ES groups were stimulated with only 0.2 mA for 30 minutes. Cervical collagen was measured in controls and following ES at various times using light-induced fluorescence (LIF) of collagen. Photographs were taken following ES, and some rats were killed, the cervices were isolated, and cervical extensibility was estimated.
  
  
  RESULTS
  LIF values of pregnant rats are significantly lower (P < .001) and extensibility greater (P < .05) in the ES treatment groups compared with the control groups on days 16 and 17 of pregnancy. Similarly LIF is lower (P < .05) and extensibility values greater (P < .05) in nonpregnant rats treated with ES. No adverse effects, including altered delivery time, pup weights, or damage to cervix, were produced by low current levels of ES needed to soften the cervix.
  
  
  CONCLUSIONS
  The following conclusions were reached: (1) application of ES rapidly produces softening and ripening of the cervix in pregnant and nonpregnant rats; (2) ES treatment does not produce early delivery; (3) the exact mechanism for ES ripening is not yet known; and (4) ES might be used clinically to ripen the cervix when needed.
authors: Guangzhou Women and Children's Medical Center, Guangzhou, China; Southern Medical University, Guangzhou, China.
authors: Dajun
authors: D
authors: Fang
authors: St Joseph's Hospital and Medical Center, Phoenix, AZ; Guangzhou Women and Children's Medical Center, Guangzhou, China.
authors: Shao-Qing
authors: SQ
authors: Shi
authors: St Joseph's Hospital and Medical Center, Phoenix, AZ.
authors: Leili
authors: L
authors: Shi
authors: Guangzhou Women and Children's Medical Center, Guangzhou, China; Southern Medical University, Guangzhou, China.
authors: Jinying
authors: J
authors: Yang
authors: Guangzhou Women and Children's Medical Center, Guangzhou, China; Southern Medical University, Guangzhou, China.
authors: Huishu
authors: H
authors: Liu
authors: Guangzhou Women and Children's Medical Center, Guangzhou, China; Southern Medical University, Guangzhou, China.
authors: Huimin
authors: H
authors: Xia
authors: St Joseph's Hospital and Medical Center, Phoenix, AZ; Guangzhou Women and Children's Medical Center, Guangzhou, China. Electronic address: drrobertgarfield@gmail.com.
authors: Robert E
authors: RE
authors: Garfield
mesh_terms: D000818:Animals; D020070:Cervical Ripening / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D036801:Parturition; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: cervical ripening; cervix; electrical stimulation; induction of labor; parturition