title: Low- and high-frequency transcutaneous electrical nerve stimulation have no deleterious or teratogenic effects on pregnant mice.
abstract: OBJECTIVE
  To evaluate the effects of application of transcutaneous electrical nerve stimulation (TENS) at low and high frequencies to the abdomens of Swiss mice throughout pregnancy.
  
  
  METHODS
  Experimental animal study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Thirty Swiss mice received TENS throughout pregnancy. They were divided into three groups (n=10): placebo, low-frequency TENS (LF group) and high-frequency TENS (HF group).
  
  
  METHODS
  In the placebo group, the electrodes were applied to the abdominal region without any electrical current. In the LF group, the frequency was 10 Hz, pulse duration was 200 μs and intensity started at 2 mA. In the HF group, the same parameters were applied and the frequency was 150 Hz. All stimulation protocols were applied for 20 min/day from Day 0 until Day 20.
  
  
  METHODS
  The pregnant mice were weighed on Days 0, 7, 14 and 20 to verify weekly weight gain by two-way analysis of variance. The numbers of fetuses, placentas, implantations, resorptions and major external fetal malformations on Day 20 were analysed using the Kruskal-Wallis test.
  
  
  RESULTS
  No significant differences were found between the placebo and TENS groups (P>0.05).
  
  
  CONCLUSIONS
  Application of low- and high-frequency TENS to the abdomens of pregnant mice did not cause any deleterious or major teratogenic effects.
authors: Department of Physical Therapy, Speech Therapy and Occupational Therapy, University of São Paulo, São Paulo, Brazil.
authors: L M
authors: LM
authors: Yokoyama
authors: Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors: L A
authors: LA
authors: Pires
authors: Department of Physical Therapy, Speech Therapy and Occupational Therapy, University of São Paulo, São Paulo, Brazil.
authors: E A Gonçalves
authors: EA
authors: Ferreira
authors: Department of Physical Therapy, Speech Therapy and Occupational Therapy, University of São Paulo, São Paulo, Brazil. Electronic address: racasaro@usp.br.
authors: R A
authors: RA
authors: Casarotto
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D051379:Mice; D011247:Pregnancy; D011897:Random Allocation; D004561:Transcutaneous Electric Nerve Stimulation / Q000009:adverse effects* / Q000379:methods*; D015430:Weight Gain
keywords: Congenital abnormalities; Fetal development; Physical therapy modalities; Pregnancy; Transcutaneous electric nerve stimulation