Objective and Subjective Aspects of Voice in Pregnancy _ € rk, *Tolgar Lu € tfi Kumral, *G€ du, *G€ *Ziya Saltu uler Bekiten, *Yavuz Atar, *Enes Atac¸, *Imran Aydog uven Yıldırım, †Aydın Kılıc¸, and *Yavuz Uyar, *yIstanbul, Turkey Summary: Objective. This study aimed to evaluate vocal changes in pregnancy according to trimesters both objectively and subjectively. Methods. Fifty pregnant women and 15 nonpregnant women were included in the study. Eighteen of the 50 pregnant women were in the first trimester, 17 in the second trimester, and 15 in the third trimester of their pregnancies. The fundamental frequency (F0), jitter, shimmer, noise-to-harmonics ratio (NHR), and minimum and maximum pitch were determined during acoustic voice analysis. Laryngologic examination was evaluated via reflux finding score (RFS). Voice Handicap Index 10 (VHI-10) was used for subjective analysis. Results. Maximum phonation time (MPT), VHI-10, and RFS were the parameters that differed significantly. MPT was significantly shorter in the third trimester. Acoustic analysis revealed that F0, jitter, shimmer, NHR, and minimum and maximum pitch values were not significantly different in any groups. RFS was higher in the first and third trimesters than the second trimester and control groups. VHI-10 scores were significantly higher in the third trimester. Conclusions. Our results showed that MPT is decreased during the third trimester, although acoustic parameters did not differ. VHI-10 results deteriorated in the third trimester significantly. Key Words: Pregnancy–Voice–Acoustic analysis–Aerodynamic–Voice Handicap Index–Quality of life. INTRODUCTION Voice is one of the main tools in human communication and social life.1 The development of the human voice does not differ between the genders until puberty. The onset of puberty causes differentiation of the human larynx and voice under the influence of sex hormones. Females have shorter vocal cords, lesser transverse and sagittal infraglottic diameters, and lesser vital capacity in comparison with males. In addition, the angle between thyroid laminas is wider in females. These differences result in a higher fundamental frequency (F0) in females.2 Besides the macroscopic changes, sex steroid hormones have effects on vocal folds via receptors in the cytoplasm and nucleus of vocal folds, and there are differences in the distribution of the receptors depending on age and sex.3 Studies on vocal changes related to hormone levels during the menstrual cycle showed that the best voice quality was obtained during the ovulatory phase, which represents the highest estrogen levels.4 On the other hand, the premenstrual period, which has the lowest estrogen levels, causes a huskier voice, vocal fatigue, and loss of higher tone.4–6 Several studies of vocal changes during pregnancy, which is characterized by higher sex steroid levels, have been published so far,7–10 but none of these studies compared the objective and subjective aspects of vocal changes during pregnancy according to trimesters in groups. Cassiraga et al9 and Hamdan et al10 studied only the third trimester. Other studies were longitudinal studies with only one pregnant woman.7,8 In addition,
Accepted for publication February 25, 2015. From the *Ear Nose and Throat Clinic, Okmeydanı Training and Research Hospital, Istanbul, Turkey; and the yGynecology and Obstetrics Clinic, Okmeydanı Training and Research Hospital, Istanbul, Turkey. Address correspondence and reprint requests to Ziya Salturk, Ear Nose and Throat Clinic, Okmeydanı Training and Research Hospital, Kaptanpas¸a Mah. Dar€ ulaceze Cad., _ S¸is¸li, Istanbul, Turkey. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-4 0892-1997/$36.00 Ó 2015 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2015.02.013
none of the previous studies evaluated subjective aspects of the issue. This study aimed to evaluate vocal changes in pregnancy according to trimesters both objectively and subjectively. MATERIALS AND METHODS Institutional review board approval was obtained from the Okmeydanı Training and Research Hospital Ethical Committee. Fifty healthy pregnant women and 15 healthy nonpregnant women were included in the study. Eighteen of the 50 pregnant women were in the first trimester, 17 in the second trimester, and 15 in the third trimester of their pregnancies. Fifteen women who had no complaint with their voices and no history of previous laryngologic disease were included in the study as control group. Voice professionals and women who had education for use of voice were not included to study to avoid bias. Women with upper respiratory tract infection, a history of laryngeal surgery or pathology, pulmonary problems, a history of head and neck radiotherapy, a history of rheumatologic disorders, smoking, or endocrinologic problems were excluded. In addition, women who had diagnosis of dysphonia, laryngeal organic pathology, or complaints related to voice before pregnancy were excluded. None of the pregnant women had polycystic ovary. All the pregnant women had single baby and none of them had cardiovascular problem or hypertension. Five pregnant women in the first trimester, four in the second trimester group, and 10 in the third trimester group had gastroesophageal reflux. Nausea was common in the first trimester: 14 women had nausea and eight of them had vomiting problem. All subjects in all groups underwent complete head and neck examinations and acoustic and aerodynamic analysis. A rigid 70 telescope was used for endoscopic examination which was performed by Karl Storz Telecam DX II (Tuttlingen, Germany). Reflux finding score (RFS) was used for the assessment of examination. Voices were recorded using an AKG D5 dynamic microphone (AKG, Vienna, Austria) kept at a distance
2
Journal of Voice, Vol. -, No. -, 2015
TABLE 1. Demographic Data of the Pregnant and Nonpregnant Women
Age Weight gain (kg)
1st Trimester (n ¼ 18), Mean ± SD
2nd Trimester (n ¼ 17), Mean ± SD
3rd Trimester (n ¼ 15), Mean ± SD
Control (n ¼ 15), Mean ± SD
P
30.16 ± 7.43 1.17 ± 0.68
27.47 ± 7.03 4.18 ± 1.13
26.40 ± 6.75 10.6 ± 2.2
28.60 ± 7.39
0.477
Abbreviation: SD, standard deviation.
of 15 cm from the lips. After a deep inspiration, the subject tried to say the vowel ‘‘ah’’ for as long as she could and repeated it three times, and the longest recording time was accepted as the maximum phonation time (MPT). Additionally, subjects were asked to read a phonetically balanced passage from a famous Turkish story titled ‘‘Diyet’’ for 40 seconds in a relaxed voice for acoustic analysis. The Praat software (Version 4.4.13; Boersma and Weenink, University of Amsterdam, Amsterdam, The Netherlands) was used for acoustic analysis. The F0, jitter, shimmer, noise-to-harmonics ratio (NHR), minimum and maximum pitch were determined during acoustic voice analysis. Subjective evaluation was performed using the Voice Handicap Index 10 (VHI-10). The Turkish version of VHI-10 was validated by Kılıc¸ et al.11 VHI-10 comprises 10 questions and is scored between 0 (never) and 4 (always). It has emotional, functional, and physical subscales with four, three, and three questions, respectively. Statistical analysis of the data was conducted using SPSS Version 17.0 (IBM, USA). Data were analyzed using descriptive statistical methods (mean and standard deviation). The analysis of variance test was used for intergroup comparisons of data that were normally distributed, and post hoc Tukey honest significant difference test was used to determine from
which group the difference arose. Results were evaluated using 95% confidence intervals, and the level of significance was set at P < 0.05.
RESULTS The mean age of the pregnant study participants in their first, second, and third trimesters was 30.16 ± 7.43, 27.47 ± 7.03, and 26.40 ± 6.75 years. The mean age of the control group was 28.60 ± 7.39 years. Age did not differ significantly between groups (Table 1). Weight gain of the women is given at Table 1. None of the women had subjective complaint about their voices. RFS results were 8.83 ± 2.00, 6.29 ± 1.96, 9.13 ± 1.55, 5.13 ± 1.92, respectively, in the first, the second, the third trimester, and the control group. Endoscopic larynx examination revealed that there was a significant difference in RFS scores (P < 0.01). Erythema/hyperemia score was higher in the first and third trimester groups that resulted in higher RFS scores in the first and the third trimester. Second trimester and control group were not different. None of the women had any structural or functional laryngologic pathology. Results of acoustic and aerodynamic analysis are summarized in
TABLE 2. Results of Acoustic and Aerodynamic Analysis and Voice Handicap Index 10 of Pregnant and Nonpregnant Women
F0 Jitter Shimmer NHR MPT* VHI-10* Pitch min Pitch max RFS*
1st Trimester (n ¼ 18), Mean ± SD
2nd Trimester (n ¼ 17), Mean ± SD
3rd Trimester (n ¼ 15), Mean ± SD
Control (n ¼ 15), Mean ± SD
df (Between Groups, Within Groups)
yP
196.72 ± 17.21 1.41 ± 0.23 0.33 ± 0.11 0.51 ± 0.14 20.72 ± 2.85 5.67 ± 3.66 96.72 ± 8.10 434.78 ± 40.11 8.83 ± 2.01
200.05 ± 14.70 1.40 ± 0.18 0.34 ± 0.10 0.49 ± 0.20 19.12 ± 3.14 5.71 ± 3.60 97.94 ± 9.32 424.29 ± 35.86 6.29 ± 1.96
204.29 ± 14.34 1.44 ± 0.17 0.34 ± 0.09 0.48 ± 0.15 15.73 ± 3.11 9.87 ± 3.46 97.67 ± 12.24 410.27 ± 51.90 9.13 ± 1.55
198.23 ± 14.34 1.40 ± 0.17 0.35 ± 0.09 0.49 ± 0.19 21.13 ± 2.95 6.07 ± 3.54 97.13 ± 11.77 420.80 ± 39.43 5.13 ± 1.92
(3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61)
0.532 0.904 0.967 0.967 >0.001 0.004 0.986 0.421 0.000
Abbreviations: SD, standard deviation; df, degrees of freedom; F0, fundamental frequency; NHR, noise-to-harmonics ratio; MPT, maximum phonation time; VHI-10, Voice Handicap Index 10; Pitch min, minimum pitch; Pitch max, maximum pitch; RFS, reflux finding score. Pregnant and nonpregnant women degrees of freedom. * P < 0.05. y Analysis of variance.
€ rk, et al Ziya Saltu
3
Voice Quality in Pregnancy
Table 2. MPT is the only parameter that differed significantly in acoustic analysis. It was significantly shorter in the third trimester. Acoustic and aerodynamic analysis revealed that F0, jitter, shimmer, and NHR values were not significantly different in any groups. VHI-10 scores were significantly higher in the third trimester.
DISCUSSION Pregnancy is a period in which psychological, physiological, and physical changes occur. The normal menstrual cycle disappears, and sex steroid hormone levels are elevated.12 In addition, emotional changes occur during the course of pregnancy.13 As a result of increased abdominal pressure, breathing patterns change and gastroesophageal reflux can be seen.14,15 During pregnancy, under the effect of sex steroids, the laryngeal mucosa becomes hyperemic and edematous. Increased permeability causes accumulation of fluid in the interstitial space, and dehydration can be seen.10,16 Physical examination results based on RFS differed among the groups because gastroesophageal reflux was more common in the third trimester and the number of women who had vomiting was higher in the first trimester group. In addition, hyperemia/erythema score was higher in the first and third trimester groups because of irritation caused by vomiting. Vocal fold edema and diffuse laryngeal edema scores were similar at all the groups. The present study revealed decreased MPT in the third trimester. There was no difference among the first trimester, the second trimester, and the control group. MPT is important for prolonged vocalization and continuous speech.17 We think that decreased abdominal volume and breathing capacity could be the reason for this finding. Our result is consistent with the report of Cassiraga et al.9 We detected no difference among groups in acoustic analysis. F0, jitter, shimmer, and NHR ratio values did not differ. F0 is the main parameter of the listener’s perception of a speaker’s pitch. It is the lowest frequency and is determined primarily by the elasticity, tension, and mass of the vocal folds.18 Jitter and shimmer percentages represent the vibrational action of the glottis and the short-term (period-to-period) irregularity of pitch and irregularity of the peak-to-peak amplitude of voice, respectively.19 An increase in the NHR ratio indicates an increase in the irregular versus regular components of voice.17 Hancock and Gross7 performed a linear study in which they followed a woman during her pregnancy and found that her voice remained stable. Hamdan et al10 analyzed 25 women who presented for delivery and stated that there were no differences in F0, NHR, and shimmer values. Cassiraga et al9 also found no difference in F0, jitter, shimmer, and NHR values. They analyzed vocal intensity and speech intensity. They reported that there was a significant change in speech intensity. Baptista and Sundberg8 studied singers and found increased phonation threshold pressure and collision threshold pressure. They concluded that these changes resulted from decreased vocal mobility and increased glottal adduction. They emphasized that their result was compatible with increased viscosity because of hormonal changes.
Hoarseness was analyzed in the literature and found to be elevated in third trimester pregnant women.9,10 Cassiraga et al9 stated that hoarseness could be a result of thickening of the vocal fold mucosa because of edema of turbulent airflow without lowering F0. Breathiness was also detected in pregnant women.9 Cassiraga et al9 emphasized that this was not a result of lowered vocal intensity but rather was associated with increased effort to overcome reduction in air loss. We studied the subjective aspect of the vocal quality in pregnancy, which was omitted in the previous studies. Each participant completed the VHI-10. It was significantly higher in third trimester women, which reflected that they had more difficulty with their voice quality. This could be related to increased breathiness and decreased MPT due to physical changes experienced in the last trimester. This is the first report to evaluate the first and second trimester voice quality in a group of patients and compare all the trimesters with each other and with a nonpregnant control group. In addition, we evaluated subjective parameters, which had not been previously studied. We detected that the first and second trimesters of pregnancy did not cause significant changes in acoustic and aerodynamic parameters. Decreased capacity in breathing function caused a decrease in MPT and an increase in VHI-10 scores. The main weaknesses of our study are the limited number of subjects and being unable to follow the same patients throughout pregnancy. Longitudinal studies which enable researchers to follow up the same patients should be performed to evaluate changes related to pregnancy. In addition, following the same group and comparing the changes during the course of pregnancy will provide more reliable data because of ruling out the structural, cultural differences which might cause bias especially in the subjective evaluation. CONCLUSIONS Our results showed that MPT is decreased during the third trimester, although acoustic parameters did not differ. VHI-10 results deteriorated in the third trimester significantly. Our study included only a small number of participants, and thus, studies following larger numbers of participants throughout pregnancy should be performed. REFERENCES 1. Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. J Voice. 1997;11:254–259. 2. Aronson AE, Bless DM. Normal voice development. In: Aronson AE, Bless DM, eds. Clinical Voice Disorders. 4th ed. New York: Thieme; 2009:10–24. 3. Newman SR, Butler J, Hammond EH, Gray SD. Preliminary report on hormone receptors in the human vocal fold. J Voice. 2000;14:72–81. 4. Raj A, Gupta B, Chowdhury A, Chadha S. A study of voice changes in various phases of menstrual cycle and in postmenopausal women. J Voice. 2010;24:363–368. 5. Abitbol J, Abitbol P, Abitbol B. Sex hormones and the female voice. J Voice. 1999;13:424–446. 6. Abitbol J, de Brux J, Millot G, Masson M-F, Mimoun OL, Pau H, Abitbol B. Does a hormonal vocal cord cycle exist in women? Study of vocal
4
7. 8. 9. 10. 11.
12.
13.
Journal of Voice, Vol. -, No. -, 2015 premenstrual syndrome in voice performers by videostroboscopy—glottography and cytology on 38 women. J Voice. 1989;3:157–162. Hancock AB, Gross HE. Acoustic and aerodynamic measures of voice during pregnancy. J Voice. 2015;29:53–58. Baptista La FM, Sundberg J. Pregnancy and the singing voice: report from a case study. J Voice. 2012;24:431–439. Cassiraga VL, Castellano AV, Abasolo J, Abin EN, Izbizky GH. Pregnancy and voice: changes during the third trimester. J Voice. 2012;26:584–586. Hamdan AL, Mahfoud L, Sibai A, Seoud M. Effect of pregnancy on the speaking voice. J Voice. 2009;23:490–493. Kilic¸ MA, Okur E, Yildirim I, et al. Reliability and validity of the Turkish version of the Voice Handicap Index [Article in Turkish]. Kulak Burun Bogaz Ihtis Derg. 2008;18:139–147. Soldin OF, Guo T, Weiderpass E, Tractenberg RE, Hilakivi-Clarke L, Soldin SJ. Steroid hormone levels in pregnancy and 1 year postpartum using isotope dilution tandem mass spectrometry. Fertil Steril. 2005;84:701–710. Elliott SA, Rugg AJ, Watson JP, Brough DI. Mood changes during pregnancy and after the birth of a child. Br J Clin Psychol. 1983;22:295–308.
14. Fill Malfertheiner S, Malfertheiner MV, Monkem€uller K, R€ohl FW, Malfertheiner P, Costa SD. Gastroesophageal reflux disease and management in advanced pregnancy: a prospective survey. Digestion. 2008;79:115–120. 15. Ali RA, Egan LJ. Gastroesophageal reflux disease in pregnancy. Best Pract Res Clin Gastroenterol. 2007;21:793–806. 16. Gordon C. Maternal Physiology. In: Gabbe S, Niebyl J, Simpson J, eds. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, PA: Churchill and Livingston; 2007:56–84. 17. Goksel AO, Toplaoglu I. Voice quality assessment via acoustic and spectrographic analysis in patients which had endolaryngeal surgery [Article in Turkish]. Kulak Burun Bogaz Ihtis Derg. 2009;19:253–258. 18. Raphael LJ, Borden GJ, Harris KS. The raw materials—phonation. In: Raphael LJ, Borden GJ, Harris KS, eds. Speech Science Primer: Physiology, Acoustics, and Perception of Speech. 5th ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2007:85–103. 19. Horii Y. Jitter and shimmer differences among sustained vowel phonations. J Speech Hear Res. 1982;25:12–14.
Accepted for publication February 25, 2015. From the *Ear Nose and Throat Clinic, Okmeydanı Training and Research Hospital, Istanbul, Turkey; and the yGynecology and Obstetrics Clinic, Okmeydanı Training and Research Hospital, Istanbul, Turkey. Address correspondence and reprint requests to Ziya Salturk, Ear Nose and Throat Clinic, Okmeydanı Training and Research Hospital, Kaptanpas¸a Mah. Dar€ ulaceze Cad., _ S¸is¸li, Istanbul, Turkey. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-4 0892-1997/$36.00 Ó 2015 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2015.02.013
none of the previous studies evaluated subjective aspects of the issue. This study aimed to evaluate vocal changes in pregnancy according to trimesters both objectively and subjectively. MATERIALS AND METHODS Institutional review board approval was obtained from the Okmeydanı Training and Research Hospital Ethical Committee. Fifty healthy pregnant women and 15 healthy nonpregnant women were included in the study. Eighteen of the 50 pregnant women were in the first trimester, 17 in the second trimester, and 15 in the third trimester of their pregnancies. Fifteen women who had no complaint with their voices and no history of previous laryngologic disease were included in the study as control group. Voice professionals and women who had education for use of voice were not included to study to avoid bias. Women with upper respiratory tract infection, a history of laryngeal surgery or pathology, pulmonary problems, a history of head and neck radiotherapy, a history of rheumatologic disorders, smoking, or endocrinologic problems were excluded. In addition, women who had diagnosis of dysphonia, laryngeal organic pathology, or complaints related to voice before pregnancy were excluded. None of the pregnant women had polycystic ovary. All the pregnant women had single baby and none of them had cardiovascular problem or hypertension. Five pregnant women in the first trimester, four in the second trimester group, and 10 in the third trimester group had gastroesophageal reflux. Nausea was common in the first trimester: 14 women had nausea and eight of them had vomiting problem. All subjects in all groups underwent complete head and neck examinations and acoustic and aerodynamic analysis. A rigid 70 telescope was used for endoscopic examination which was performed by Karl Storz Telecam DX II (Tuttlingen, Germany). Reflux finding score (RFS) was used for the assessment of examination. Voices were recorded using an AKG D5 dynamic microphone (AKG, Vienna, Austria) kept at a distance
2
Journal of Voice, Vol. -, No. -, 2015
TABLE 1. Demographic Data of the Pregnant and Nonpregnant Women
Age Weight gain (kg)
1st Trimester (n ¼ 18), Mean ± SD
2nd Trimester (n ¼ 17), Mean ± SD
3rd Trimester (n ¼ 15), Mean ± SD
Control (n ¼ 15), Mean ± SD
P
30.16 ± 7.43 1.17 ± 0.68
27.47 ± 7.03 4.18 ± 1.13
26.40 ± 6.75 10.6 ± 2.2
28.60 ± 7.39
0.477
Abbreviation: SD, standard deviation.
of 15 cm from the lips. After a deep inspiration, the subject tried to say the vowel ‘‘ah’’ for as long as she could and repeated it three times, and the longest recording time was accepted as the maximum phonation time (MPT). Additionally, subjects were asked to read a phonetically balanced passage from a famous Turkish story titled ‘‘Diyet’’ for 40 seconds in a relaxed voice for acoustic analysis. The Praat software (Version 4.4.13; Boersma and Weenink, University of Amsterdam, Amsterdam, The Netherlands) was used for acoustic analysis. The F0, jitter, shimmer, noise-to-harmonics ratio (NHR), minimum and maximum pitch were determined during acoustic voice analysis. Subjective evaluation was performed using the Voice Handicap Index 10 (VHI-10). The Turkish version of VHI-10 was validated by Kılıc¸ et al.11 VHI-10 comprises 10 questions and is scored between 0 (never) and 4 (always). It has emotional, functional, and physical subscales with four, three, and three questions, respectively. Statistical analysis of the data was conducted using SPSS Version 17.0 (IBM, USA). Data were analyzed using descriptive statistical methods (mean and standard deviation). The analysis of variance test was used for intergroup comparisons of data that were normally distributed, and post hoc Tukey honest significant difference test was used to determine from
which group the difference arose. Results were evaluated using 95% confidence intervals, and the level of significance was set at P < 0.05.
RESULTS The mean age of the pregnant study participants in their first, second, and third trimesters was 30.16 ± 7.43, 27.47 ± 7.03, and 26.40 ± 6.75 years. The mean age of the control group was 28.60 ± 7.39 years. Age did not differ significantly between groups (Table 1). Weight gain of the women is given at Table 1. None of the women had subjective complaint about their voices. RFS results were 8.83 ± 2.00, 6.29 ± 1.96, 9.13 ± 1.55, 5.13 ± 1.92, respectively, in the first, the second, the third trimester, and the control group. Endoscopic larynx examination revealed that there was a significant difference in RFS scores (P < 0.01). Erythema/hyperemia score was higher in the first and third trimester groups that resulted in higher RFS scores in the first and the third trimester. Second trimester and control group were not different. None of the women had any structural or functional laryngologic pathology. Results of acoustic and aerodynamic analysis are summarized in
TABLE 2. Results of Acoustic and Aerodynamic Analysis and Voice Handicap Index 10 of Pregnant and Nonpregnant Women
F0 Jitter Shimmer NHR MPT* VHI-10* Pitch min Pitch max RFS*
1st Trimester (n ¼ 18), Mean ± SD
2nd Trimester (n ¼ 17), Mean ± SD
3rd Trimester (n ¼ 15), Mean ± SD
Control (n ¼ 15), Mean ± SD
df (Between Groups, Within Groups)
yP
196.72 ± 17.21 1.41 ± 0.23 0.33 ± 0.11 0.51 ± 0.14 20.72 ± 2.85 5.67 ± 3.66 96.72 ± 8.10 434.78 ± 40.11 8.83 ± 2.01
200.05 ± 14.70 1.40 ± 0.18 0.34 ± 0.10 0.49 ± 0.20 19.12 ± 3.14 5.71 ± 3.60 97.94 ± 9.32 424.29 ± 35.86 6.29 ± 1.96
204.29 ± 14.34 1.44 ± 0.17 0.34 ± 0.09 0.48 ± 0.15 15.73 ± 3.11 9.87 ± 3.46 97.67 ± 12.24 410.27 ± 51.90 9.13 ± 1.55
198.23 ± 14.34 1.40 ± 0.17 0.35 ± 0.09 0.49 ± 0.19 21.13 ± 2.95 6.07 ± 3.54 97.13 ± 11.77 420.80 ± 39.43 5.13 ± 1.92
(3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61) (3, 61)
0.532 0.904 0.967 0.967 >0.001 0.004 0.986 0.421 0.000
Abbreviations: SD, standard deviation; df, degrees of freedom; F0, fundamental frequency; NHR, noise-to-harmonics ratio; MPT, maximum phonation time; VHI-10, Voice Handicap Index 10; Pitch min, minimum pitch; Pitch max, maximum pitch; RFS, reflux finding score. Pregnant and nonpregnant women degrees of freedom. * P < 0.05. y Analysis of variance.
€ rk, et al Ziya Saltu
3
Voice Quality in Pregnancy
Table 2. MPT is the only parameter that differed significantly in acoustic analysis. It was significantly shorter in the third trimester. Acoustic and aerodynamic analysis revealed that F0, jitter, shimmer, and NHR values were not significantly different in any groups. VHI-10 scores were significantly higher in the third trimester.
DISCUSSION Pregnancy is a period in which psychological, physiological, and physical changes occur. The normal menstrual cycle disappears, and sex steroid hormone levels are elevated.12 In addition, emotional changes occur during the course of pregnancy.13 As a result of increased abdominal pressure, breathing patterns change and gastroesophageal reflux can be seen.14,15 During pregnancy, under the effect of sex steroids, the laryngeal mucosa becomes hyperemic and edematous. Increased permeability causes accumulation of fluid in the interstitial space, and dehydration can be seen.10,16 Physical examination results based on RFS differed among the groups because gastroesophageal reflux was more common in the third trimester and the number of women who had vomiting was higher in the first trimester group. In addition, hyperemia/erythema score was higher in the first and third trimester groups because of irritation caused by vomiting. Vocal fold edema and diffuse laryngeal edema scores were similar at all the groups. The present study revealed decreased MPT in the third trimester. There was no difference among the first trimester, the second trimester, and the control group. MPT is important for prolonged vocalization and continuous speech.17 We think that decreased abdominal volume and breathing capacity could be the reason for this finding. Our result is consistent with the report of Cassiraga et al.9 We detected no difference among groups in acoustic analysis. F0, jitter, shimmer, and NHR ratio values did not differ. F0 is the main parameter of the listener’s perception of a speaker’s pitch. It is the lowest frequency and is determined primarily by the elasticity, tension, and mass of the vocal folds.18 Jitter and shimmer percentages represent the vibrational action of the glottis and the short-term (period-to-period) irregularity of pitch and irregularity of the peak-to-peak amplitude of voice, respectively.19 An increase in the NHR ratio indicates an increase in the irregular versus regular components of voice.17 Hancock and Gross7 performed a linear study in which they followed a woman during her pregnancy and found that her voice remained stable. Hamdan et al10 analyzed 25 women who presented for delivery and stated that there were no differences in F0, NHR, and shimmer values. Cassiraga et al9 also found no difference in F0, jitter, shimmer, and NHR values. They analyzed vocal intensity and speech intensity. They reported that there was a significant change in speech intensity. Baptista and Sundberg8 studied singers and found increased phonation threshold pressure and collision threshold pressure. They concluded that these changes resulted from decreased vocal mobility and increased glottal adduction. They emphasized that their result was compatible with increased viscosity because of hormonal changes.
Hoarseness was analyzed in the literature and found to be elevated in third trimester pregnant women.9,10 Cassiraga et al9 stated that hoarseness could be a result of thickening of the vocal fold mucosa because of edema of turbulent airflow without lowering F0. Breathiness was also detected in pregnant women.9 Cassiraga et al9 emphasized that this was not a result of lowered vocal intensity but rather was associated with increased effort to overcome reduction in air loss. We studied the subjective aspect of the vocal quality in pregnancy, which was omitted in the previous studies. Each participant completed the VHI-10. It was significantly higher in third trimester women, which reflected that they had more difficulty with their voice quality. This could be related to increased breathiness and decreased MPT due to physical changes experienced in the last trimester. This is the first report to evaluate the first and second trimester voice quality in a group of patients and compare all the trimesters with each other and with a nonpregnant control group. In addition, we evaluated subjective parameters, which had not been previously studied. We detected that the first and second trimesters of pregnancy did not cause significant changes in acoustic and aerodynamic parameters. Decreased capacity in breathing function caused a decrease in MPT and an increase in VHI-10 scores. The main weaknesses of our study are the limited number of subjects and being unable to follow the same patients throughout pregnancy. Longitudinal studies which enable researchers to follow up the same patients should be performed to evaluate changes related to pregnancy. In addition, following the same group and comparing the changes during the course of pregnancy will provide more reliable data because of ruling out the structural, cultural differences which might cause bias especially in the subjective evaluation. CONCLUSIONS Our results showed that MPT is decreased during the third trimester, although acoustic parameters did not differ. VHI-10 results deteriorated in the third trimester significantly. Our study included only a small number of participants, and thus, studies following larger numbers of participants throughout pregnancy should be performed. REFERENCES 1. Titze IR, Lemke J, Montequin D. Populations in the U.S. workforce who rely on voice as a primary tool of trade: a preliminary report. J Voice. 1997;11:254–259. 2. Aronson AE, Bless DM. Normal voice development. In: Aronson AE, Bless DM, eds. Clinical Voice Disorders. 4th ed. New York: Thieme; 2009:10–24. 3. Newman SR, Butler J, Hammond EH, Gray SD. Preliminary report on hormone receptors in the human vocal fold. J Voice. 2000;14:72–81. 4. Raj A, Gupta B, Chowdhury A, Chadha S. A study of voice changes in various phases of menstrual cycle and in postmenopausal women. J Voice. 2010;24:363–368. 5. Abitbol J, Abitbol P, Abitbol B. Sex hormones and the female voice. J Voice. 1999;13:424–446. 6. Abitbol J, de Brux J, Millot G, Masson M-F, Mimoun OL, Pau H, Abitbol B. Does a hormonal vocal cord cycle exist in women? Study of vocal
4
7. 8. 9. 10. 11.
12.
13.
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