Table 1.
Summary of studies included in meta-analysis
| Study | Sample description | Measures | Study design | Stimuli | Correlation with self-reported sexual arousal | Correlation with perception of genital arousal | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Female | Male | Genital | Subjective | Female | Male | Female | Male | |||
| Studies reporting within-subjects correlations | ||||||||||
| Abel, Blanchard, Murphy, Becker, and Djenderedjian (1981) | – | 21 volunteers (mean age = 24) | Barlow gauge | Likert | Compared two methods of quantifying penile response: percent of full erection and AUC (area under penile response curve). | 12 explicit presentations of deviant and non- deviant film and audio. | – | .74/.67 (% erection/ AUC) | – | .82/.82 (% erection/AUC) |
| 6 outpatients (mean age missing) | 24 explicit presentations of homosexual and heterosexual film, audio, and fantasy. | – | .68/.74 | – | .88/.83 | |||||
| 8 sex offenders (mean age missing) | 24 explicit presentations of deviant and nondeviant film, audio, and fantasy. | – | .57/.56 | – | .78/.75 | |||||
| Abrahamson, Barlow, Beck, and Athanasiou (1985) | 10 volunteers (mean age = 39.5) | Barlow gauge | Lever | Effects of distraction and stimulus intensity on functional and dysfunctional men. | 3 explicit film clips. | – | .61 | – | – | |
| 10 with erectile dysfunction (mean age = 43.6) | Correlations reported across distraction and film conditions. | – | .32 | – | – | |||||
| Bancroft (1971) | 25 combined heterosexual & homosexual sexology patients (mean age missing) | Strain gauge | Likert | Sexual response to preferred and nonpreferred sexual stimuli | 10 slides (5 nude male and 5 nude female). | – | .74 | – | – | |
| Barlow, Sakheim, and Beck (1983) | 12 students (mean age = 26.3) | Barlow gauge | Lever | Effect of anxiety induced by shock threat. Correlation reported for no-shock condition. | 1 explicit film. | – | .68 | – | – | |
| Beck and Barlow (1986) | 12 with secondary erectile dysfunction (mean age = 43.8) | Barlow gauge | Lever | Effect of attentional focus and anxiety (induced by shock threat). | 4 explicit heterosexual films of foreplay. | – | .70 (no shock threat) | – | – | |
| 12 volunteers (mean age = 40.9) | Correlations reported across focus conditions (sensate and spectator focus) and group. | – | .52 (shock threat) | – | – | |||||
| Beck, Barlow, and Sakheim (1983) | 8 volunteers (mean age = 35) | Barlow gauge | Lever | Effects of attentional focus (self versus partner). | 6 explicit black-and-white heterosexual films of foreplay. | – | .23 | – | – | |
| 8 with sexual dysfunction (mean age = 42) | Correlations reported across focus conditions. | – | .13 | – | – | |||||
| Beck, Barlow, Sakheim, and Abrahamson (1987) | 16 volunteers (mean age = 24) | Barlow gauge | Lever | Effects of shock threat, selective attention, thought content and affect. | 4 explicit heterosexual audiotaped clips. | – | .75 | – | – | |
| Correlations reported across shock conditions. | – | – | – | – | ||||||
| Chivers et al. (2007) | 27 heterosexual students & volunteers (mean age = 22.3) | 27 heterosexual students & volunteers (mean age = 24) | VPA/Strain gauge | Lever | Gender and orientation differences in response to sexual activities vs. gender of actors in sexual films. | 16 film clips (mating bonobos, nude exercise, masturbation & copulation clips). | .51 | .82 | – | – |
| 20 homosexual students & volunteers (mean age = 28) | 17 homosexual students & volunteers (mean age = 25.1) | Correlations reported across several stimuli. | .56 | .85 | – | – | ||||
| Cranston-Cuebas et al. (1993) | 10 volunteers (mean age = 43.9) | Barlow gauge | Lever | Effects of misattribution manipulation using placebo. | 3 explicit heterosexual films depicting 2 females, 1 male. | – | .23 | – | – | |
| 10 with secondary erectile dysfunction (mean age = 48.8) | Correlations reported across manipulation conditions (detraction, enhancement, neutral). | – | .45 | – | – | |||||
| Dekker and Everaerd (1988) | 48 students (mean age = 22) | 48 students (mean age = 23) | Barlow gauge | Likert | Attentional effects on sexual arousal. | 15 explicit heterosexual slides, one audiotaped narrative, and sexual fantasy. | – | .43 | – | – |
| VPA | Correlations averaged across stimuli and focus conditions (focus on situation/action and focus on sexual response). | .37 | – | – | – | |||||
| VBV | .16 | – | – | – | ||||||
| Farkas, Sine, and Evans (1979) | 30 students (mean age = 26.4) | Strain gauge | Lever | Effects of distraction, performance demand and stimulus explicitness on sexual arousal. | 1 explicit or nonexplicit (clothed, heterosexual sensual interaction) black-and-white film without audio. | – | .49 (attention) | – | – | |
| – | .35 (distraction) | – | – | |||||||
| Korff and Geer (1983) | 10 students (mean age missing) | VPA | Visual-auditory scale | Relationship between focus condition and concordance. | 10 erotic heterosexual slides. | .48/.47/.69 (scale/light/tone) | – | – | – | |
| 12 students (mean age missing) | Correlations for 3 subjective scales: 5-point rating, light, and sound (tone). | 10 erotic heterosexual slides. | .87/.82/.90 | – | – | – | ||||
| Genital focus group. | ||||||||||
| 14 students (mean age missing) | Non-genital focus group. | 10 erotic heterosexual slides. | .86/.82/.79 | – | – | – | ||||
| Laan and Everaerd (1995b) | 16 students (mean age = 21) | VPA | Lever | Habituation of sexual arousal. | 11 slides, depicting heterosexual sex and nude or semi-nude male or female models. | .38 | – | – | – | |
| 19 students (mean age = 20.5) | 21 explicit heterosexual films (female-centered). | – | – | .28 | – | |||||
| 20 students (mean age = 20.5) | 21 uniform presentations of a cunnilingus scene. | – | – | .24 | – | |||||
| Laan, Everaerd, van der Velde et al. (1995) | 17 students (mean age = 20) | VPA | Lever | Association between subjective and genital arousal. | 21 presentations of explicit, heterosexual film clip (female-centered). | – | – | .26 | – | |
| 14 students (mean age = 20) | 21 explicit heterosexual film clips (female-centered). Clips were different but showed the same content. | – | – | .30 | – | |||||
| 19 students (mean age = 20) | 21 explicit heterosexual film clips (female-centered), increasing in sexual intensity. | – | – | .61 | – | |||||
| Mavissakalian et al. (1975) | 6 heterosexual students (mean age = 22.6) | Barlow gauge | Lever | Responses to erotic stimuli in homosexual and heterosexual males. | 16 explicit black-and-white film clips, depicting heterosexual activity, single female activity, homosexual male or lesbian activity. | – | .69/.74 (within/between) | – | – | |
| 6 homosexual sexology patients (mean age = 21.5) | Correlations reported across two sessions as within-subjects and between-subjects. | – | .70/.57 | – | – | |||||
| Meuwissen and Over (1992) | 10 students (mean age = 26.9) | VPA/VBV | Likert | Correlation between subjective and genital arousal across phases of menstrual cycle. | 9 explicit film clips and 15 fantasies. Film varied in content and target stimuli. Fantasy varied in content and included atypical sex. | .62 /.69 (menstrual) | – | – | – | |
| .72/.69 (post-menstrual) | – | – | – | |||||||
| Correlations calculated across all 24 stimulus trials for each phase. | .60/.68 (luteal) | – | – | – | ||||||
| .69/.73 (pre-menstrual) | – | – | – | |||||||
| Rellini et al. (2005) | 22 volunteers (mean age = 27) | VPA | Likert | Relationship between physiological and subjective arousal in women. | 1 explicit heterosexual film. | −.08 | – | −.13 | – | |
| Rowland and Heiman (1991) | 9 volunteers (mean age = 36.1) | Strain gauge | Likert | Arousal before (Time 1) and after (Time 2) sex therapy program. | 2 explicit heterosexual audiotapes, narrated by female. | – | .74/.81 (time 1/time 2) | – | .80/.72 (time 1/time 2) | |
| 9 with sexual dysfunction (mean age = 41.8) | – | – | Correlations reported across sensate focus and instructional demand. | Unstructured fantasy. | – | .61/.73 | – | .67/.52 | ||
| Rubinsky et al. (1985) | 6 volunteers (mean age = 28) | 10 volunteers (mean age = 28) | VPA or strain gauge | Likert | Testing validity of groin skin temperature. | 1 explicit black-and-white heterosexual film. | .09 | .43 | – | – |
| VBV | .53 | – | – | – | ||||||
| Thermography | .63 | .31 | – | – | ||||||
| Sakheim, Barlow, Abrahamson, and Beck (1987) | 10 healthy volunteers (mean age = 38.1) | Barlow gauge | Lever | Distinguishing between psychogenic and organogenic erectile dysfunction. | 1 explicit heterosexual film clip. | – | – | – | .72 | |
| 10 with psychogenic sexual dysfunction (mean age = 44.6) | – | – | – | .50 | ||||||
| 10 with organogenic sexual dysfunction (mean age = 55.8) | – | – | – | .26 | ||||||
| Strassberg, Kelly, Caroll, and Kircher (1987) | 13 volunteers (mean age = 30) | Barlow gauge | Likert | Sexual arousal and premature ejaculation. | 3 explicit film clips. | – | .54 | – | – | |
| 13 with premature ejaculation (mean age = 33) | – | .49 | – | – | ||||||
| Webster and Hammer (1983) | 8 heterosexual volunteers (mean age = 27) | Barlow gauge | Likert | Thermographic measurement of arousal. | 3 explicit heterosexual film clips (black and white). | – | .95 | – | – | |
| Thermography | – | .94 | – | – | ||||||
| Wincze, Hoon, and Hoon (1977) | 6 volunteers (mean age = 24.3) | – | VPA | Likert | Comparing cognitive and physiological responses. | 17 explicit film clips, depicting heterosexual intercourse, group sex and single homosexual scene. | .41 | – | – | – |
| Thermography | .27 | – | – | – | ||||||
| Wincze et al. (1980) | 8 volunteers (mean age = 22.2) | 6 volunteers (mean age = 20.6) | VPA or Barlow gauge | Likert | Effects of subjective monitoring. | 2 heterosexual film clips, depicting low arousal (kissing) and high arousal (intercourse). | .15 | .69 | – | – |
| Correlations reported across arousal conditions. | ||||||||||
| Wincze and Qualls (1984) | 8 homosexual volunteers (mean age = 26) | 8 homosexual volunteers (mean age = 26) | VPA or Barlow gauge | Likert | Sexual orientation and sexual arousal to preferred and nonpreferred sexual stimuli. | 5 explicit films depicting female–male sex, male–male sex, female–female sex, group sex and neutral. | .69 | .86 | – | – |
| Wormith (1986) | – | 36 combined sex offenders and non-sex offenders (mean age = 30.2) | Strain gauge | Likert | Physiological and cognitive aspects of deviant sexual arousal. Correlations reported across content conditions. | 12 explicit slides, depicting adult male, adult female, child male, child female, heterosexual couple and neutral scene. | – | .53 | – | – |
| Studies reporting between-subjects correlations | ||||||||||
| Abramson et al. (1981) | 37 students (mean age = 28) | 32 students (mean age = 28) | Thermography | Likert | Discriminant validity of thermography. | 1 explicit story. | .70 | .73 | – | – |
| Adams et al. (1985) | 24 students (mean age = 20.1) | VPA | Likert | Effect of cognitive distraction. | 1 explicit heterosexual audiotape. | – | – | .37 (no distraction) | – | |
| – | – | .74 (distraction) | – | |||||||
| Adams, Wright, and Lohr (1996) | 64 students (mean age = 20.3) | Strain gauge | Likert | Homophobia and sexual arousal. | 1 explicit heterosexual film. | – | .57 | – | .64 | |
| 1 explicit female–female film. | – | .63 | – | .66 | ||||||
| 1 explicit male–male film. | – | .53 | – | .64 | ||||||
| Bach et al. (1999) | 26 volunteers (mean age = 32.2) | Barlow gauge | Likert | False negative feedback and sexual arousal. | 2 explicit heterosexual films with no audio. | – | .29 (film 1) | – | .28 (film 1) | |
| – | −.16 (film 2) | – | .37 (film 2) | |||||||
| Basson and Brotto (2003) | 34 post-menopausal with sexual dysfunction (mean age = 56.6) | VPA | Likert | Drug trial for sildenafil citrate. | 1 explicit heterosexual film. | .19 | – | .30 | – | |
| Bellerose and Binik (1993) | 58 combined volunteers, hysterectomy & oophorectomy patients (mean age = 46) | VPA | Likert | Body image and sexuality in oophorectomized women. | 1 explicit heterosexual film. | .23 | – | .28 | – | |
| Lever | Correlations reported across two sessions. | .24 | – | .28 | – | |||||
| Bernat, Calhoun, and Adams (1999) | 34 students (mean age = 19.9) | Strain gauge | Likert | Arousal to consensual and nonconsensual sex. | 2 explicit audiotaped clips paired with nude female slide. | – | – | – | .64 | |
| Both et al. (2004) | 10 students (mean age = 22.6): Study 1 | 10 students (mean age = 22) | VPA or Barlow gauge | Likert | Sexual behavior (study 1) and responsiveness to stimuli (study 2) following laboratory-induced sexual stimulation. | 1 explicit heterosexual film. | −.26 | .45 | .13 | .60 |
| 24 students & volunteers (mean age = 24.5): Study 2 | 24 students & volunteers (mean age = 27) | −.02 | .03 | −.06 | −.06 | |||||
| Both, Everaerd, Laan, and Gooren (2005) | 28 students (mean age = 22) | 19 students (mean age = 22) | VPA or Barlow gauge | Likert | Effects of dopamine on arousal in men vs. women. | 2-min fantasy period (unstructured). | .13 | .67 | .16 | .65 |
| 1 explicit heterosexual film. | .31 | .49 | .16 | .68 | ||||||
| Both, Van Boxtel, Stekelenburg, Everaerd, and Laan (2005) | 26 students (mean age = 22.9) | VPA | Likert | Spinal reflexes and arousal to films of increasing intensity. | 1 low-intensity heterosexual film (kissing). | −.23 | – | .12 | – | |
| 1 medium-intensity heterosexual film (kissing & caressing). | .30 | – | .37 | – | ||||||
| 1 high-intensity heterosexual film (intercourse). | .20 | – | .04 | – | ||||||
| Bradford and Meston (2006) | 38 volunteers (mean age = 25.4) | VPA | Likert | Effect of anxiety. | 1 explicit heterosexual film. | .35 | – | .32 | – | |
| Brauer et al. (2006) | 24 volunteers (mean age = 26.6) | VPA | Likert | Arousal to coital vs. non-coital sex in women with dyspareunia. | 1 explicit heterosexual film depicting oral sex. | .43/.25/.31 (oral/coitus/average) | – | .43/.37/.43 (oral/coitus/average) | – | |
| 48 with dyspareunia (mean age = 28.2) | Correlations reported for oral film, coitus film, or average across both films. | 1 explicit heterosexual film depicting coitus. | −.14/.21/.03 | – | .00/.27/.15 | – | ||||
| Brauer et al. (2007) | 48 volunteers (mean age = 23.9) | VPA | Likert | Pain-related fear and dyspareunia. | 1 explicit heterosexual film. | .18 | .24 | – | – | |
| 48 with dyspareunia (mean age = 25.9) | −.05 | .12 | – | – | ||||||
| Briddell et al. (1978) | 48 heterosexual students (mean age = 22) | Strain gauge | Likert | Effects of alcohol and cognitive set. | 1 explicit heterosexual audiotape (consensual). | – | .57 | – | .73 | |
| 1 explicit audiotape of forcible rape scenario. | – | .42 | – | .56 | ||||||
| Fantasy. | – | .55 | – | .60 | ||||||
| Briddell and Wilson (1976) | 48 students (mean age = 20) | Strain gauge | Likert | Effects of alcohol and alcohol expectancy. | 2 explicit heterosexual films. | – | – | – | .66 | |
| Correlations reported across four alcohol and two expectancy conditions. | – | – | – | – | ||||||
| Brotto and Gorzalka (2002) | 25 pre-menopausal (mean age = 24.5) | VPA | Likert | Effects of hyperventilation on sexual arousal in pre- and postmenopausal women. | 1 explicit heterosexual film. | .14 | – | .19 | – | |
| 21 pre-menopausal (mean age = 47.8) | Correlations reported across two sessions. | .42 | – | .48 | – | |||||
| 25 post-menopausal (mean age = 56) | .26 | – | .30 | – | ||||||
| Brotto et al. (2004) | 30 volunteers (mean age = 23.4) | VPA | Likert | Patterns of sexual response in sexually dysfunctional women. | 1 explicit heterosexual film. | −.38 | – | −.22 | – | |
| 31 with sexual dysfunction (mean age = 30.6) | .17 | – | .08 | – | ||||||
| Cerny (1978) | 10 students given no feedback (mean age = 19.9) | VBV/VPA | Likert | Biofeedback and voluntary control. | 1 explicit heterosexual film. | .72/.00 (nonsig) | – | – | – | |
| 10 students given accurate feedback (mean age = 19.9) | Correlations reported across 10 trials. | .00/.00 (nonsig) | – | – | – | |||||
| 10 volunteers given false feedback (mean age = 19.9) | .00/.00 (nonsig) | – | – | – | ||||||
| Chivers (2003) | 69 heterosexual volunteers (mean age = 24.6) | 39 heterosexual volunteers (mean age = 29.6) | VPA or strain gauge | Likert | Relationship between sexual arousal to preferred and nonpreferred sexual stimuli and sexual orientation. | 3 explicit film clips depicting gay, lesbian, or heterosexual sex. | .36/.52/.41 (gay/lesbian/heterosexual) | .58/.48/.51 | – | – |
| 19 homosexual volunteers (mean age = 28.4) | 29 homosexual volunteers (mean age = 32.7) | .57/.59/.49 | .55/.67/.41 | – | – | |||||
| 17 bisexual volunteers (mean age = 25.1) | 30 bisexual volunteers (mean age = 29.6) | .39/.55/.56 | .08/.48/.19 | – | – | |||||
| Danjou, Alexandre, Warot, Lacomblez, and Puech (1988) | 10 volunteers (mean age = 23) | Strain gauge | Visual analog scale | Effects of apomorphine and yohimbine. | 50 explicit slides. | – | .01 | – | – | |
| Elliott and O’Donohue (1997) | 24 volunteers (mean age missing) | VPA | Likert | Effects of anxiety and distraction. | 1 erotic heterosexual audiotape. | .02 (control) | – | – | – | |
| 2 erotic heterosexual audiotapes. | .16 (mean of high and low distraction) | – | – | – | ||||||
| Exton et al. (1999) | 10 students (mean age = 24.8) | VPA | Likert | Effect of masturbation. | 1 explicit heterosexual film. | .45 | – | – | – | |
| Geer, Morokoff, and Greenwood (1974) | 14 students (mean age missing) | VPA/VBV | Likert | Development of device to measure vaginal blood volume. | 1 explicit heterosexual film. | .00/.00 (nonsig) | – | – | – | |
| George et al. (2006) | 65 students & volunteers (mean age = 25.6) | Strain gauge | Likert | Effects of alcohol. | 2 explicit heterosexual film clips. | – | .50 | – | – | |
| 60 students & volunteers (mean age = 25) | – | .45 | – | – | ||||||
| Gerard (1982) | 10 mastectomy patients (mean age = 47) | VPA | Likert | Mastectomy and sexual functioning. | 1 erotic heterosexual film. | .15 | – | – | – | |
| 10 volunteers (mean age = 48) | .74 | – | – | – | ||||||
| Graham, Janssen, and Sanders (2000) | 27 students (90% heterosexual) (mean age = 26.9) | VPA | Visual/auditory scale | Effects of fragrance on arousal, mood and menstrual cycle. | 3 explicit heterosexual films (2 female-centered). | −.17 | – | −.18 | – | |
| Correlations reported across conditions. | 3 min of unstructured fantasy. | – | −.16 | – | −.09 | |||||
| Heiman (1977) | 59 students (mean age = 19) | 39 students (mean age = 19) | VPA or strain gauge | Likert | Male and female sexual arousal. | 8 erotic heterosexual audiotapes and 4 unstructured sexual fantasies. | .56 | .54 | – | – |
| Heiman (1980) | 55 married or unmarried volunteers (mean age = 30) | VPA | Likert | Physiological, affective and contextual correlates of sexual response. | 1 explicit heterosexual film with no audio. | .32 | – | – | – | |
| 1 explicit heterosexual audiotape, narrated by male. | .39 | – | – | – | ||||||
| Heiman and Hatch (1980) | 16 heterosexual volunteers (mean age = 35.4) | Strain gauge | Likert | Affective and physiological correlates of male sexual response. | 1 explicit heterosexual audiotape, narrated by female. | – | .78 | – | .82 | |
| Unstructured fantasy. | – | .66 | – | .79 | ||||||
| Heiman and Rowland (1983) | 16 volunteers (mean age = 34) | Strain gauge | Likert | Effects of demand instructions on functional and dysfunctional men. | 1 explicit heterosexual audiotape. | – | .67 | – | .00 (nonsig) | |
| 1 explicit heterosexual audiotape. | – | .65 | – | .00 (nonsig) | ||||||
| Fantasy. | – | .67 | – | .00 (nonsig) | ||||||
| 14 with sexual dysfunction(mean age = 39) | 1 explicit heterosexual audiotape. | – | .55 | – | .00 (nonsig) | |||||
| 1 explicit heterosexual audiotape. | – | .55 | – | .60 | ||||||
| Fantasy. | – | .83 | – | .00 (nonsig) | ||||||
| Heiman et al. (2001) | 12 pre- and post-menopausal (mean age missing) | VPA | Likert | Comparison between VPA, VBV and pelvic imaging (regional blood volume, RBV, and clitoral blood volume, CBV) | 1 explicit film. | .65 | – | .73 | – | |
| VBV | .47 | – | .54 | – | ||||||
| RBV | .51 | – | .42 | – | ||||||
| CBV | .50 | – | .45 | – | ||||||
| Hoon (1980) | 23 volunteers (mean age = 26) | VPA/VBV | Likert | Effects of biofeedback. | 3-min fantasy period. | .06/.26 (no feedback) | – | – | – | |
| .14/.25 (feedback) | – | – | – | |||||||
| Islam et al. (2001) | 6 with sexual arousal disorder (mean age = 40.4) | VPA | Likert | Drug trial for topical alprostadil USP. Correlations reported for placebo condition. | 1 explicit film. | −.34 | – | .43 | – | |
| Janssen, Vorst, Finn, and Bancroft (2002) | 39 students (mean age = 23) | Rigiscan | Likert | Evaluate predictive value of self-report scales across low- (LD) and high-demand (HD) conditions, with or without distraction. | 1 explicit heterosexual film (female-centered). | – | .55 (LD) | – | .66 (LD) | |
| – | .62 (LD + distraction) | – | .82 (LD + distraction) | |||||||
| – | .27 (HD) | – | .47 (HD) | |||||||
| 1 erotic film clip depicting coercive heterosexual interactions. | – | .62 (HD + distraction) | – | .70 (HD + distraction) | ||||||
| – | .54 (LD) | – | .60 (LD) | |||||||
| – | .63 (HD) | – | .77 (HD) | |||||||
| Julien and Over (1988) | 24 students (mean age = 26) | Strain gauge | Likert | Habituation study across five modalities: film audiotape, fantasy, pictures, and text. | 8 explicit heterosexual stimuli per modality, depicting activities progressing from couple undressing to male ejaculation. | – | .27 (film) | – | – | |
| – | .52 (audiotape) | – | – | |||||||
| – | .76 (fantasy) | – | – | |||||||
| – | .62 (stills) | – | – | |||||||
| – | .54 (text) | – | – | |||||||
| Kukkonen et al. (2007) | 10 students (mean age = 20.8) | 10 students (mean age = 21.4) | Thermography | Likert | Validity of thermography among men and women. Both within- and between-subjects correlations reported. | 1 explicit heterosexual film. | .40/.60 (between-subjects/within-subjects) | .71 (between) | – | – |
| Laan et al. (1993) | 46 students (mean age = 20.7) | VPA | Lever and Likert | Performance demand vs. no demand and sexual arousal. Subjective sexual arousal assessed during stimulus (DS) with a lever and post-stimulus (PS) with a Likert scale. | 1 explicit heterosexual film. | .26/.39 (DS-demand/PS-demand) | – | – | – | |
| .28/.46 (DS-none/ PS-none) | – | – | – | |||||||
| 1 2-min unstructured fantasy period. | .00/.00 (DS-demand/PS-demand, nonsig) | – | – | – | ||||||
| .00/.00 (DS-none/ PS-none, nonsig) | – | – | – | |||||||
| Laan et al. (1994) | 47 students & volunteers (mean age = 25) | VPA | Likert | Effects of male- vs. female-centered stimuli. | 1 explicit heterosexual film (female-centered). | −.05 | – | .09 | – | |
| Correlations averaged over film order. | 1 explicit heterosexual film (male-centered). | .16 | – | .32 | – | |||||
| Laan, Everaerd, and Evers (1995) | 49 students (mean age = 22.3) | VPA | Visual analog scale | Response specificity and construct validity of VPA and VBV. | 1 explicit heterosexual film (female-centered). | .33 | – | .00 (nonsig) | – | |
| 1 explicit heterosexual film, depicting sexual threat. | .47 | – | .31 | – | ||||||
| VBV | 1 explicit heterosexual film (female-centered). | .38 | – | .11 | – | |||||
| 1 explicit heterosexual film, depicting sexual threat. | .45 | – | .00 (nonsig) | – | ||||||
| Laan, Everaerd, van Berlo, and Rijs (1995) | 13 volunteers (mean age = 22.5) | VPA | Likert | Effects of mood. | 1 explicit heterosexual film clip, and 5 min of unstructured fantasy. | .28/−.06 (film/ fantasy) | – | – | – | |
| Laan et al. (2001) | 38 post-menopausal (mean age = 54) | VPA | Likert | Effects of tibolone. | 1 erotic heterosexual film clip, depicting foreplay (female-centered). | .37 | – | .41 | – | |
| 1 explicit heterosexual film clip (female-centered). | .56 | – | .35 | – | ||||||
| 1 3-min unstructured fantasy period (fantasy 1). | .52 | – | .33 | – | ||||||
| 1 3-min unstructured fantasy period (fantasy 2). | .42 | – | .51 | – | ||||||
| Laan et al. (2002) | 12 volunteers (mean age = 23.5) | VPA | Likert | Sildenafil drug trial. Correlations reported for placebo condition. | 1 explicit heterosexual film. | .32 | – | .26 | – | |
| Lake Polan et al. (2003) | 20 volunteers (mean age = 24.9) | VPA | Likert | Sexual arousal in women to female-centered films. | 1 explicit heterosexual film with sound. | .16 | – | – | – | |
| 1 explicit heterosexual film without sound. | .16 | – | – | – | ||||||
| Lange, Wincze, Zwick, Feldman, and Hughes (1981) | 24 students (mean age = 22.6) | Barlow gauge | Lever | Effects of performance demand and epinephrine. Correlation for no drug/demand condition. | 1 explicit heterosexual film clip (black and white, no audio). | – | – | – | .68 | |
| Lohr, Adams, and Davis (1997) | 24 students (mean age = 19) | Strain gauge | Likert | Sexual arousal in sexually coercive vs. non-coercive men. | 7 explicit heterosexual audiotape clips, depicting consent, verbal threat, rape, or nonsexual aggression, with nude female slide. | – | .76 | – | .87 | |
| 24 students; mix of controls & sexually coercive (mean age = 19.5) | 7 explicit heterosexual audiotape clips, depicting consent, verbal threat, rape or nonsexual aggression. | – | .86 | – | .85 | |||||
| Malamuth and Check (1980) | 71 students (mean age missing) | Strain gauge | Likert | Sexual arousal to rape depictions. | 3 explicit audiotape clips, depicting consensual or non-consensual sex. | – | .54 | – | – | |
| 69 students (mean age missing) | 1 explicit audiotape clip, depicting non-consensual sex. | – | .31 | – | – | |||||
| McCall and Meston (2007) | 16 volunteers (mean age = 27.3) | VPA | Likert | Effects of false and negative feedback among sexually dysfunctional women. | 1 explicit heterosexual film. | .51/.27 (positive feedback/negative feedback) | – | .39/.21 (positive feedback/negative feedback) | – | |
| 15 with sexual dysfunction (mean age = 35.3) | .28/.03 | – | .44/.05 | – | ||||||
| McConaghy (1969) | 37 homosexual men (mean age = 26.5) | Volumetric | Method not reported | Responses after aversion therapy. Correlation reported across male and female stimuli. | 20 explicit film clips. | – | .00 (nonsig) | – | – | |
| Messé and Geer (1985) | 30 students (mean age = 20) | VPA | Likert | Effect of Kegel exercise on sexual arousal. | 4-min unstructured fantasy periods. | .00 (nonsig) | – | – | – | |
| Correlation reported across all sessions and treatment groups. | ||||||||||
| Meston and Gorzalka (1995) | 35 students (mean age = 24.6) | VPA/VBV | Likert | Effect of exercise. | 1 explicit heterosexual video clip. | – | – | −.19/−.23 | – | |
| Correlation reported for no exercise condition. | – | – | – | – | ||||||
| Meston, Gorzalka, and Wright (1997) | 15 volunteers (mean age = 25.6) | VPA/VBV | Likert |
Effects of clonidine and sympathetic activation via exercise. Correlations reported for placebo conditions. |
1 explicit heterosexual film clip. | – | – | .25/.19 (no exercise) | – | |
| – | – | .27/.56 (exercise) | – | |||||||
| Meston and Heiman (1998) | 20 students (mean age = 25.8) | VPA | Likert | Effects of ephedrine sulfate on sexual arousal. | 1 explicit heterosexual film clip. | .23 | – | .14 | – | |
| Correlations reported for the placebo condition. | – | – | ||||||||
| Meston and Worcel (2002) | 24 post-menopausal with sexual arousal disorder (mean age = 53.7) | VPA | Likert | Drug trial for yohimbine plus l-arginine glutamate. | 1 explicit heterosexual film (female-centered). | −.01 | – | −.03 | – | |
| Meston (2004) | 15 hysterectomy patients with fibroids (mean age = 41.4) | VPA | Likert | Effects of hysterectomy and exercise. | 1 explicit heterosexual film. | .06/.04 (no exercise/exercise) | – | .17/.39 (no exercise/exercise) | – | |
| −.37/.12 | – | −.31/−.07 | – | |||||||
| 17 with fibroids only (mean age = 40) | ||||||||||
| Meston (2006) | 16 volunteers (mean age = 28.9) | VPA | Likert | State and trait self-focused attention in sexually functional vs. dysfunctional women. | 1 explicit heterosexual film. | .31/.31 (no focus/self-focus) | – | – | – | |
| 16 with sexual dysfunction (mean age = 32.3) | .11/−.25 | – | – | – | ||||||
| Meston and McCall (2005) | 13 students (mean age = 26.6) | VPA | Likert | Dopamine and norepinephrine responses to erotic stimuli in sexually functional vs. dysfunctional women. | 1 explicit heterosexual film. | .14 | – | .15 | – | |
| 9 with sexual dysfunction (mean age = 31.4) | .19 | – | .08 | – | ||||||
| Meuwissen and Over (1990) | 7 students (mean age = 28.8) | VBV | Likert | Habituation of sexual arousal. | 2 explicit heterosexual film clips with no audio. | .46 | – | – | – | |
| Correlation reported for dishabituation (novel) stimulus only. | 2 structured fantasies using descriptive slides. | .61 | – | – | – | |||||
| Miller (1999) | 82 students (mean age = 19.4) | Strain gauge | Lever | Sexual arousal to coercive and non-coercive stimuli. | 1 explicit heterosexual film clip. | – | .19 | – | – | |
| Mitchell, DiBartolo, Brown, and Barlow (1998) | 24 volunteers (mean age = 38.5) | Barlow gauge | Lever | Effects of mood. Correlations reported for control conditions, separately for two sessions. | 1 explicit film clip. | – | .93/.99 (session 1/2) | – | – | |
| Morokoff (1985) | 62 students (mean age = 19) | VPA | Likert | Effects of guilt, repression and experience. | 1 explicit heterosexual film. | .42 | – | – | – | |
| Unstructured fantasy. | .00 (nonsig) | – | – | – | ||||||
| Morokoff and Heiman (1980) | 11 healthy volunteers (mean age = 30) | VPA | Likert | Comparing sexually functional and dysfunctional women before (session 1) and after (session 2) therapy. | 1 explicit heterosexual audiotape, narrated by male. | −.55/−.65 (session 1/2) | – | – | – | |
| 1 explicit heterosexual film with no sound. | .00/.00 (nonsig) | – | – | – | ||||||
| 3 unstructured fantasies. | .24/.00 (nonsig) | – | – | – | ||||||
| 11 with sexual dysfunction (mean age = 29) | Correlation reported across 3 fantasies. | 1 explicit heterosexual audiotape, narrated by male. | .00/.00 (nonsig) | – | – | – | ||||
| 1 explicit heterosexual film with no sound. | .00/.00 (nonsig) | – | – | – | ||||||
| 3 unstructured fantasies. | .00/.25 (nonsig) | – | – | – | ||||||
| O’Donohue and Geer (1985) | 40 students (mean age = 20.5) | Barlow & Strain gauge | Likert | Effects of habituation. Correlation reported for first trial. | 1 explicit slide (either nude or heterosexual activity). | – | .45 | – | – | |
| Osborn and Pollack (1977) | 12 students (mean age = 25.2) | VPA/VBV | Likert | Effects of two types of erotic literature. Rank order correlations reported. | 10 explicit heterosexual stories (“hardcore”). | −.40/.00 (nonsig) | – | – | – | |
| 10 heterosexual stories (“erotic realism”). | .00/.00 (nonsig) | – | – | – | ||||||
| Palace and Gorzalka (1990) | 16 students (mean age = 28) | VBV | Likert | Effects of anxiety in women with vs. without sexual dysfunction. | 2 explicit heterosexual film clips. | .00 (nonsig) | – | – | – | |
| 16 with sexual dysfunction (mean age = 30) | .00 (nonsig) | – | – | – | ||||||
| Palace and Gorzalka (1992) | 16 students (mean age = 26) | VBV | Likert | Sexual arousal patterns in women with vs. without sexual dysfunction. | 1 erotic heterosexual film clip with no sound, 1 explicit heterosexual film clip with no sound, and 1 erotic heterosexual film clip with sound. | .50/.00/.00 (erotic no sound/ explicit no sound/explicit with sound, nonsig) | – | – | – | |
| 16 with sexual dysfunction (mean age = 26) | .00/ .00/ .00 (nonsig) | – | – | – | ||||||
| Payne et al. (2007) | 20 volunteers (mean age = 22.2) | Thermography | Likert | Effects of arousal on genital and non-genital sensations in women with vulvar vestibulitis syndrome vs. controls. | 1 explicit heterosexual film. | .30 | – | – | – | |
| 20 with vulvar vestibulitis syndrome (mean age = 23.8) | −.05 | – | – | – | ||||||
| Peterson and Janssen (2007) | 26 students (mean age = 20.3) | 19 students (mean age = 20.7) | VPA or Rigiscan | Likert | Role of affect in predicting arousal in men and women. | 1 explicit heterosexual film (female-centered). | .06 | .46 | – | – |
| 1 explicit heterosexual film (male-centered). | .20 | .52 | – | – | ||||||
| 1 explicit heterosexual film (coercive). | .12 | .26 | – | – | ||||||
| 1 explicit heterosexual film (runner-up) | .01 | .51 | – | – | ||||||
| Rogers, Van de Castle, Evans, and Critelli (1985) | 10 students (low SAI group) (mean age = 23) | VPA | Likert | VPA during erotic conditions and sleep. Groups defined by Sexual Arousal Inventory (SAI) score. | 1 explicit heterosexual film. | .36/−.18 (film/fantasy) | – | – | – | |
| 10 students (high SAI group) (mean age = 27) | 1 10-min period of unstructured fantasy. | .45/.30 | – | – | – | |||||
| Sakheim et al. (1985) | 8 heterosexual volunteers (mean age = 35) | Barlow gauge | Lever | Sexual orientation and sexual arousal. | 2 explicit heterosexual films, gay (male–male) films, and lesbian (female–female) films. | – | .84/.67/.77 (heterosexual/gay/lesbian) | – | – | |
| 8 homosexual volunteers (mean age = 35) | Correlations reported across 2 sessions. | – | .57/.71/.31 | – | – | |||||
| Salemink and van Lankveld (2006) | 21 volunteers (mean age = 23.3) | VPA | Likert | Effects of distraction among sexually functional vs. dysfunctional women. | 1 explicit heterosexual film. | −.02 | – | – | – | |
| 20 with sexual dysfunction (mean age = 29.4) | Correlations for no distraction condition. | .14 | – | – | – | |||||
| Schacht et al. (2007) | 42 volunteers (sexually abused or non-abused; mean age = 24.7) | VPA | Likert | Effects of alcohol and instructional set among sexually abused vs. non-abused women. | 2 explicit heterosexual film clips. | .01 | – | .03 | – | |
| Correlations across alcohol and demand conditions. | – | – | – | – | ||||||
| Schaefer et al. (1976) | 8 healthy volunteers (mean age = 25) | Barlow gauge | % erection estimate | Concordance using % estimate of erection. | Explicit text describing heterosexual intercourse. | – | – | – | .86 | |
| Schreiner-Engel et al. (1981) | 30 healthy volunteers (mean age = 25) | VPA | Likert | Concordance across phases of the menstrual cycle. | 1 explicit heterosexual film clip. | .11/.18/.09 (follicular/ ovulatory/ luteal) | – | – | – | |
| 1 5-min unstructured fantasy (fantasy 1). | .07/.05/.34 | – | – | – | ||||||
| 1 5-min unstructured fantasy (fantasy 2). | .32/.09/.45 | – | – | – | ||||||
| Seal et al. (2005) | 16 students & volunteers (mean age = 21.8) | VPA | Likert | Sexual arousal before and after oral contraception use. | 1 explicit heterosexual film. | .50/.83 (before /after) | – | .11/.57 (before /after ) | – | |
| Slob et al. (1990) | 24 with diabetes (mean age = 33.6) | Thermography | Likert | Sexual arousal in women with diabetes. | 1 explicit group sex film, depicting 2 females and 1 male. | .22 | – | – | – | |
| 10 healthy volunteers (mean age = 31.2) | .69 | – | – | – | ||||||
| Slob et al. (1996) | 9 healthy volunteers (mean age = 31) | Thermography | Likert | Sexual arousal and the menstrual cycle with and without vibrotactile stimulation | 1 explicit heterosexual film. Follicular phase. | −.26/.05(with/without vib) | – | .26/.07 | – | |
| 11 healthy volunteers (mean age = 34) | 1 explicit heterosexual film. Luteal phase. | .15/.38 | – | .39/.17 | – | |||||
| Stock (1983) | 75 students (mean age missing) | VPA | Likert | Effects of sexually violent stimuli. | 1 explicit heterosexual audiotape, depicting mutual consent (n = 15). | .17 | – | – | – | |
| 1 explicit heterosexual audiotape, depicting woman aroused by sexual assault (n = 15). | .33 | – | – | – | ||||||
| 1 explicit heterosexual audiotape, depicting pain and negative emotional reactions of female rape victim (n = 15). | .29 | – | – | – | ||||||
| 1 explicit heterosexual audiotape, depicting realistic sexual assault (n = 75). | .00 (nonsig) | – | – | – | ||||||
| ter Kuile, Vigeveno, and Laan (2007) | 29 volunteers (mean age = 23.4) | VPA | Likert | Stress and arousal in women. Correlation reported for no-stress group. | 1 explicit heterosexual film. | .56 | – | – | – | |
| Tollison et al. (1979) | 10 heterosexual students (mean ages missing for all samples) | Barlow gauge | Likert | Sexual arousal in heterosexual, bisexual & homosexual men. | 1 explicit gay film clip. | – | −.15/.65/.45/.63 (gay film/het. film/nude males/nude females) | – | .48/.88/.64/.63 | |
| 10 bisexual volunteers | 1 explicit heterosexual film clip. | – | .59/.30/.64/.51 | – | .82/−.21/.37/.65 | |||||
| Slides of nude males. | ||||||||||
| 10 homosexual volunteers | Slides of nude females. | – | .25/.14/.63/−.52 | – | .17/.50/.90/.66 | |||||
| Van Lankveld and van den Hout (2004) | 26 volunteers (mean age = 47.9) | Barlow gauge | % erection estimate | Distraction and level of stimulation in sexually functional vs. dysfunctional men. | 1 explicit heterosexual film (high explicit). | – | .28/.17 (high explicit/low explicit) | – | – | |
| 23 with sexual dysfunction (mean age = 55.7) | Correlations for listen-only condition. | 1 heterosexual film (low explicit). | – | .17/−.03 | – | – | ||||
| Weisberg, Brown, Wincze, and Barlow (2001) | 52 students (mean age = 20.8) | Strain gauge | Likert/% Maximum | Causal attributions and sexual arousal. | 1 explicit heterosexual film clip. | – | .46/.46 | – | .78/.78 | |
| Wilson and Lawson (1976) | 40 students (mean age = 20) | Strain gauge | Likert | Effects of alcohol and alcohol expectancy. | 1 explicit black-and-white heterosexual film. | – | – | – | .53 | |
| Wilson and Lawson (1978) | 40 students (mean age = 22) | VPA | Likert | Effects of alcohol and alcohol expectancy. | 1 explicit black-and-white heterosexual film | .11 | – | .04 | – | |
| 1 explicit black-and-white lesbian film. | .24 | – | .15 | – | ||||||
| Studies reporting both mixed- and between- subjects correlations | ||||||||||
| Apperloo et al. (2006) | 10 volunteers (mean age = 23) | VPA | Likert | Effects of testosterone. Correlation calculated across conditions. | 1 explicit heterosexual film, 2 neutral film clips and fantasy period. | .51 | – | – | – | |
| Cohen, Rosen, and Goldstein (1985) | 18 mixed sample of men with vs. without sexual dysfunction (mean age = 46.1) | Strain gauge | Likert | EEG study. Correlations reported across 2 sessions. | 2 explicit heterosexual films | – | .71 | – | – | |
| 2 explicit heterosexual audiotapes. | – | .86 | – | – | ||||||
| Gaither (2001) | 20 students (mean age = 20.3) | Strain gauge | Likert | Validity and reliability of new measures of sexual arousal. Correlations reported using 5 mean physiological responses to the 4 sexual activities plus neutral clips. | 40 explicit heterosexual film clips, depicting fellatio, cunnilingus, vaginal penetration and anal penetration. | – | .80 | – | – | |
| Gaither and Plaud (1997) | 18 students (mean age = 23.7) | Strain gauge | Likert | Effects of sound and type of sexual activity in sexual films. Correlations reported across sound conditions. | 6 explicit heterosexual films, depicting 6 different activities. | – | .78 | – | – | |
| Gaither, Rosenkranz, Amato-Henderson, Plaud, and Bigwood (1996) | 14 students (mean age missing) | Strain gauge | Likert | Sexual arousal and condom use in sexual stimuli. Correlations reported across condom conditions. | 10 explicit audiotaped clips narrated by female. | – | −.07 | – | – | |
| Hall, Binik, and DiTomasso (1985) | 20 students (mean age = 22) | Strain gauge | Likert | Concordance. | 1 explicit heterosexual audiotape | – | .66 | – | – | |
| Correlations reported across gender of narrator. | – | – | – | – | ||||||
| Heard-Davidson, Heiman, and Kuffel (2007) | 10 post-menopausal women (mean age = 56.8) | VPA | Likert | Effects of testosterone in postmenopausal women. Correlations reported for placebo conditions. | 5 explicit heterosexual film clips. | .67 | – | .71 | – | |
| Heiman et al. (1991) | 7 volunteers (mean age = 32) | VPA | Likert | Sexual arousal and endocrine response. | 2 explicit heterosexual film clips. | .00 (nonsig) | – | – | – | |
| 6 volunteers (mean age = 32) | 1 explicit heterosexual film clip. | .00 (nonsig) | – | – | – | |||||
| Henson et al. (1977) | 10 students (mean age = 30) | Thermography | Likert | Validity of thermography. | 1 explicit heterosexual film. | – | – | .57 | – | |
| Henson and Rubin (1978) | 8 students (mean age = 28) | VBV | Likert | Comparison between two measures of genital arousal. | 1 explicit heterosexual film. | .40 | – | – | – | |
| Thermography | .84 | – | – | – | ||||||
| Henson et al. (1979) | 8 volunteers (mean age = 24) | VPA | Likert | Comparing different measures of arousal in women. | 1 explicit heterosexual film. | – | – | .76 | – | |
| VBV | – | – | .42 | – | ||||||
| Thermography | .82 | |||||||||
| Hoon et al. (1982) | 13 students (mean age = 24) | VPA/VBV | Likert | Menstrual cycle and arousal. | 5 erotic heterosexual audiotapes. | – | – | .00/.33 (nonsig) | – | |
| Thermography | 3 min of unstructured fantasy. | – | – | .00 (nonsig) | – | |||||
| VPA/VBV | Correlations reported across 5 sessions and cycle phases. | .00/.00 (nonsig) | ||||||||
| Kockott, Feil, Ferstl, Aldenhoff, and Besigner (1980) | 16 volunteers (mean age = 32.4) | Strain gauge | Visual-auditory scale | Sexual arousal and male sexual dysfunction. Correlations are averaged across 2 sessions. | 2 heterosexual films, depicting foreplay. | – | .18 | – | – | |
| 8 volunteers (mean age = 45.1) | – | .33 | – | – | ||||||
| 10 diabetic men (mean age = 47) | – | .23 | – | – | ||||||
| 8 with primary erectile dysfunction (mean age = 34) | – | .52 | – | – | ||||||
| 8 with secondary erectile dysfunction (mean age = 34) | – | −.10 | – | – | ||||||
| 7 with premature ejaculation during all sex acts (mean age = 33.6) | – | .39 | – | – | ||||||
| 9 with premature ejaculation during intercourse only (mean age = 33.6) | – | .57 | – | – | ||||||
| Koukounas and McCabe (2001) | 30 students (mean age = 29.5) | Strain gauge | Likert | Effects of attention and emotion. | 5 explicit heterosexual films (no audio). | – | .83 | – | – | |
| Koukounas and Over (1999) | 16 students (mean age = 21.9) | Strain gauge | Likert | Effects of attention and habituation. Correlations calculated over 18 habituation trials. | 18 explicit heterosexual film clips (no audio) | – | .91 | – | – | |
| Letourneau and O’Donohue (1997) | 25 students (mean age = 21) | VPA | Likert | Classical conditioning of female arousal. Correlations reported across 5 sessions. | 50 explicit heterosexual film clips (female-centered). | .25 | – | – | – | |
| Pras et al. (2003) | 9 medical patients treated with radiotherapy for gynecological cancer (mean age = 49.2) | VPA | Likert | Assessing feasibility of VPA to measure effects of radiotherapy on sexual function. Correlations reported across 3 films. | 3 explicit heterosexual films (5, 9 and 10 min in length). | .50 | – | – | – | |
| 8 healthy volunteers (mean age = 43.3) | −.12 | – | – | – | ||||||
| Slob et al. (1991) | 12 volunteers not using oral contraceptives (mean age = 25.9) | Thermography | Likert | Menstrual cycle phase and sexual arousal. | 2 explicit heterosexual film clips (female-centered). | .10 | – | .33 | – | |
| 12 volunteers using oral contraceptives (mean age = 22.8) | .49 | – | .75 | – | ||||||
| Smith and Over (1987) | 8 students (mean age = 28) | Strain gauge | Likert | Habituation of fantasy-induced arousal. | 2 min of structured fantasy. | – | .79 | – | – | |
| Steinman, Wincze, Sakheim, Barlow, and Mavissakalian (1981) | 8 students (mean age = 23) | 8 students (mean age = 22) | VPA or strain gauge | Continuous/Likert | Comparison of male and female arousal. Correlations reported across all 4 films. | 4 explicit films, depicting heterosexual sex, group sex and homosexual sex (male–male or female–female). | .48/.52 | .80/.80 | – | – |
| Wilson, Niaura, and Adler (1985) | 32 students (mean age = 22.5) | Strain gauge | Visual-auditory scale | Effects of alcohol and selective attention. Same stimulus shown 4 different times under different conditions (instructional set and alcohol manipulation). | 4 explicit heterosexual audiotapes, narrated by male. | – | .78 | – | – | |
| Wouda et al. (1998) | 18 with dyspareunia (mean age = 25) | VPA | Likert | Vaginal plethysmography in women with dyspareunia. | 3 explicit heterosexual film clips, depicting oral sex and vaginal intercourse. | .08 | – | – | – | |
| 16 controls (mean age = 25) | .25 | – | – | – | ||||||
Notes: Correlations for average genital and subjective arousal reported when both max and mean values are available. Correlations are reported for control and placebo conditions, unless otherwise noted. Correlations that were reported as statistically nonsignificant were assigned value of zero (identified in table as “nonsig”). Sample is heterosexual unless stated otherwise
VPA vaginal pulse amplitude, VBV vaginal blood volume