title: Birth control pills and nonprofessional voice: acoustic analyses.
abstract: OBJECTIVE
  Two studies are presented here. Study 1 was aimed at evaluating whether the voice characteristics of women who use birth control pills that contain different progestins differ from the voice characteristics of a control group. Study 2 presents a meta-analysis that combined the results of Study 1 with those from 3 recent studies that compared voices of women who use and do not use birth control pills.
  
  
  METHODS
  In Study 1, voice samples from 30 women with no history of voice training, who use pills with different progestins (drospirenone, desogestrel, gestodene), and 10 women who do not use the pill were recorded at specific time points across the menstrual cycle and were analyzed acoustically. In Study 2, results from Study 1 were analyzed jointly with results from three recent studies, which used similar methodologies.
  
  
  RESULTS
  Results of Study 1 did not reveal acoustic differences in sustained phonation of vowels across the pill groups and controls. Results of the meta-analysis performed in Study 2 indicated that pill users exhibited lower jitter and shimmer values on sustained vowels, whereas no difference of fundamental frequency was observed among women who use the pill.
  
  
  CONCLUSIONS
  These results support findings from previous studies, which suggested that no adverse effect on voice was detected among nonprofessional speakers who use new-generation monophasic birth control pills, for the measures studied. Furthermore, results of the meta-analysis suggested that some acoustic properties of the voice, which are reflected in perturbation measures in sustained vowels, may be improved among women who use the pill.
authors.affiliation: Department of Communication Disorders, Sheba Medical Center, Tel Hashomer 52621, Israel. oferamir@post.tau.ac.il
authors.forename: Ofer
authors.initials: O
authors.lastname: Amir
authors.forename: Tal
authors.initials: T
authors.lastname: Biron-Shental
authors.forename: Esther
authors.initials: E
authors.lastname: Shabtai
mesh_terms: D000328:Adult; D000736:Androstenes / Q000008:administration & dosage / Q000494:pharmacology; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000008:administration & dosage / Q000494:pharmacology*; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage / Q000494:pharmacology; D017135:Desogestrel / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006801:Humans; D008234:Lynestrenol / Q000008:administration & dosage / Q000494:pharmacology; D000451:Mineralocorticoid Receptor Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D009652:Norpregnenes / Q000008:administration & dosage / Q000494:pharmacology; D012044:Regression Analysis; D013061:Speech Acoustics; D013068:Speech Production Measurement; D013637:Tape Recording; D014833:Voice Quality / Q000187:drug effects*
chemical_list: D000736:Androstenes; D003276:Contraceptives, Oral; D003280:Contraceptives, Oral, Synthetic; D000451:Mineralocorticoid Receptor Antagonists; D009652:Norpregnenes; C033273:Gestodene; D017135:Desogestrel; C035144:drospirenone; D008234:Lynestrenol