title: Effects of the menstrual cycle and oral contraception on singers' pitch control.
abstract: OBJECTIVE
  Difficulties with intonation and vibrato control during the menstrual cycle have been reported by singers; however, this phenomenon has not yet been systematically investigated.
  
  
  METHODS
  A double-blind randomized placebo-controlled trial assessing effects of the menstrual cycle and use of a combined oral contraceptive pill (OCP) on pitch control in singing is presented. Audio-electrolaryngograph recordings were made and blood samples were taken from 9 singers in each of the 3 phases of the menstrual cycle both under the placebo and the OCP conditions for a total of 6 months. Participants sang an exercise consisting of an ascending octave followed by a descending major triad, starting on pitches F4 and B4. Pitch control was assessed in terms of the octave's deviations from pure intonation and of the vibrato rate and extent.
  
  
  RESULTS
  Significant differences were found between the 3 phases of the cycle regarding octave size only for pitch F5 during OCP use. Significant vibrato rate differences between placebo and OCP conditions were found only for pitch F5.
  
  
  CONCLUSIONS
  OCP use may have an effect on pitch control in singers. Possible explanations point to a complex interaction between hormonal milieu and pitch control, enhancing the need for longitudinal studies.
authors.affiliation: University of Aveiro, Portugal. filipa.la@ua.pt
authors.forename: Filipa M B
authors.initials: FM
authors.lastname: Lã
authors.forename: Johan
authors.initials: J
authors.lastname: Sundberg
authors.forename: David M
authors.initials: DM
authors.lastname: Howard
authors.forename: Pedro
authors.initials: P
authors.lastname: Sa-Couto
authors.forename: Adelaide
authors.initials: A
authors.lastname: Freitas
mesh_terms: D000736:Androstenes / Q000494:pharmacology; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology*; D004311:Double-Blind Method; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000187:drug effects / Q000502:physiology*; D010699:Phonation / Q000187:drug effects* / Q000502:physiology; D013068:Speech Production Measurement; D018709:Statistics, Nonparametric; D014831:Voice / Q000187:drug effects* / Q000502:physiology
chemical_list: D000736:Androstenes; D003277:Contraceptives, Oral, Combined; D004997:Ethinyl Estradiol; C035144:drospirenone