Reconsidering the refractory period: an exploratory study of women's post-orgasmic experiences.
Article Type: Report
Subject: Women (Physiological aspects)
Prolactin (Physiological aspects)
Prolactin (Research)
Orgasm (Research)
Authors: Humphries, Aliisa K.
Cioe, Jan
Pub Date: 09/22/2009
Publication: Name: The Canadian Journal of Human Sexuality Publisher: SIECCAN, The Sex Information and Education Council of Canada Audience: Academic Format: Magazine/Journal Subject: Psychology and mental health Copyright: COPYRIGHT 2009 SIECCAN, The Sex Information and Education Council of Canada ISSN: 1188-4517
Issue: Date: Fall, 2009 Source Volume: 18 Source Issue: 3
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: Canada Geographic Code: 1CANA Canada
Accession Number: 210595139
Full Text: Abstract: The post-orgasmic refractory period in men is characterized by penile sensitivity, detumescence, and reduced arousabilty. The literature suggests that a comparable phenomenon either does not occur in women or is less marked. The topic has thus been understudied in women. Similarities in the prenatal genital development of the sexes and in their adult post-orgasmic release of prolactin, a hormone associated with the refractory period in men, suggest the possibility of a refractory period in women. The present study of 174 female university students (mean age 25 years) focused on the occurrence of post-orgasmic clitoral hypersensitivity which we hypothesized would parallel the post-orgasmic penile glans sensitivity reported in men. Overall, 96% of the participants reported post-orgasmic clitoral hypersensitivity and a comparable percentage indicated aversiveness to further post-orgasm clitoral stimulation. Follow-up individual online interviews with 11 participants provided further elaboration on the experience. The findings invite a reconsideration of a refractory period in women and highlight the need for further research on post-orgasmic experiences that includes the female perspective.

Introduction

Masters and Johnson (1966) described a post-orgasmic refractory period in men "which develops as the last, irregular, nonexpulsive contractions of the urethra occur and is maintained until sexual tension in the male has been reduced to low excitement--phase levels of response" (p. 283). They also reported that "the female has no such refractory period" (p. 283). This latter observation may explain why much of the available literature on the post-orgasmic period has focused predominantly on the male perspective. The male refractory period has been defined as the period of time immediately after orgasm in which men experience hypersensitivity in the glans of the penis to the extent that it causes stimulation to be aversive (Yilmaz & Aksu, 2000). The male refractory period is further defined by the inability to achieve an erection during this period, and by detumescence of the penis (Yilmaz & Aksu, 2000). The tacit agreement in the literature and in human sexuality textbooks appears to have been that there is no such female post-orgasmic refractory period (Hyde, DeLamater, & Byers, 2009; Rathus, Nevid, Fichner-Rathus, & Herold, 2009) or that "postorgasmic loss of arousability is generally believed to be less marked in women than in men" (Bancroft, 1999, p. 290). However, similarities in prenatal development of genital anatomy in males and females and in some key aspects of their post-orgasmic endocrinology offer good reasons to reconsider the refractory period in women.

In terms of the prenatal development of genital anatomy, males and females have a similar undifferentiated genital tubercle which differentiates early in fetal development into the penis in males (in response to the testosterone they produce prenatally) and into the clitoris in females (in response to other built in differentiation processes that occur in the absence of testosterone during that critical period). This homologous development of reproductive anatomy in females and males is well-described in some human sexuality texts (e.g., Levay & Baldwin, 2008) and in greater detail in reviews on the topic (e.g., Vilain, 2000). The normal clitoris has corporeal bodies that are smaller than but homologous to those of the penis (Baskin, Erol, Liu, Kurzrock, & Cunha, 1999). The fetal clitoris consists of two corporeal bodies similar to those in the male penis (Baskin et al., 1999).

The corpus spongiosum in females, as in males, has been shown to extend from the bilateral vestibular bulbs to the glans of the clitoris which also consists of spongious tissue (Van Turnhout, Hage, & Van Diest, 1995). Large bundles of nerves run along the corporeal bodies which extend completely around the tunica of the clitoris in a similar fashion to that of the penis (Baskin et al., 1999). The clitoris, like the penis, is innervated by the neuronal nitric oxide synthase (nNOS)-positive branches from the cavernous nerve (Yucel, De Souza, & Baskin, 2004). It is also likely that erections of the penis and clitoris are controlled by similar brain mechanisms (e.g., Carlson, 2004). Based on the homologous genital anatomy of men and women, one might anticipate that the refractory period, if it is mediated peripherally, would have an anatomical basis for being present in women, as well as men, but expressed differently.

The post-orgasmic refractory period, which occurs in other animals, may also be mediated by the brain and nervous system. For example, the medial preoptic area (MPOA) has been shown to be important for sexual arousal, copulatory behaviour, and the refractory period of male rats (Hoffman, Gerall, & Kalivas, 1987; Oomura, Aou, Koyama, Fujita, & Yoshimatsu, 1988). Merari and Ginton (1975) found that stimulation of the MPOA increases sexual behaviour and reduces the length of the refractory period in rats. Hansen and Hagelsrum (1984) also found that lesions to the MPOA thwart sexual behaviour in rats. During the refractory period, the concentration of gamma-aminobutyric acid increases in male rats (Qureshi & Sodersten, 1986); female rats were not assessed in this study. McIntosh and Barfield (1984a) found that the central dopaminergic pathways are important aspects of a normal post-ejaculatory refractory period in male rats and also that the noradrenergic system is essential for normal male rat copulatory behaviour (McIntosh & Barfield, 1984b). Crowley, Nock, and Feder (1978) similarly found that the noradrenergic system also plays a role in female rat copulatory behaviour. When Hansen and Ross (1983) injected rats with neurotoxins that depleted spinal synaptosomal uptake of radiolabeled noradrenalin and serotonin, they found that female rats were less sexually receptive and that male rats had longer post-ejaculatory refractory periods. The rat neural and neurotransmitter literature therefore suggests that there may be parallel refractory period-related processes occurring in males and females.

Sex similarities in post-orgasmic endocrinology also provide insights into the refractory period. For example, the neuroendocrine response to orgasm in humans is characterized by a post-orgasmic surge of prolactin (Kruger et al., 2003a). Blood levels of prolactin do not change through the different stages of sexual arousal (Exton et al., 2000). It is only at the time of orgasm that prolactin is released in both men and women as reflected by the increased levels of the hormone in blood plasma at this time (Exton et al., 1999; Exton et al., 2001). Prolactin levels remain elevated for over an hour following orgasm (Kruger, Haake, Hartmann, Schedlowski, & Exton, 2002). However, Kruger et al. (2002) point out that there are probably other mechanisms involved in the physiological regulation of erection in men post-orgasmically since the male refractory period is typically more on the order of 15 minutes rather than 60 minutes.

The release of prolactin is thought to be largely responsible for the post-orgasmic refractory period seen in men (Kruger et al., 2003b) and elevated prolactin in the blood can be considered as a regulatory mechanism, or feedback loop, that helps control sexual libido and, therefore, sexual behaviour (Exton et al., 2000; Kruger et al., 2003b; Kruger, Hartmann, & Schedlowski, 2005). Consistent with this idea, it has been shown that people with hyperprolactinemia (i.e., increased levels of prolactin) have a curbed sexual appetite or loss of sex drive (Kruger et al., 2003b). Similarly, both male and female animals with hyperprolactinemia show pronounced reductions in sexual approach behaviour (Kruger et al., 2002). In cases where men have a non-ejaculatory (dry) orgasm, there is no prolactin surge and no subsequent refractory period (Dunn & Trost, 1989). This suggests that without post-orgasmic prolactin release there would be no male refractory period.

Some men have been found not to release prolactin at the time of orgasm even with ejaculation, and therefore, their blood plasma levels of prolactin do not increase (Haake et al., 2002). These men do not have a post-orgasmic refractory period and their orgasms are followed by neither detumescence nor hypersensitivity of the glans of the penis. These men are therefore capable of achieving multiple orgasms accompanied by ejaculation (Haake et al., 2002). These findings suggest that the orgasm-induced prolactin release, rather than ejaculation itself, may cause the subsequent refractory period in normal men.

Women also release prolactin at the rime of orgasm (Kruger et al., 2002). It is possible that this release acts as a type of regulatory mechanism as it does in men. Hyperprolactinemia in women is associated with a decrease in orgasmic frequency (Koppelman, Parry, Hamilton, Alagna, & Loriaux, 1987). If prolactin released at the time of orgasm in men causes hypersensitivity of the glans of the penis, it is possible that prolactin released at orgasm in women would have a similar effect on the glans of the clitoris given the homology of the structures involved.

Based on the foregoing background, we considered it important to determine whether women experience anything like the refractory period that is so well documented in men. We hypothesized that women would report a post-orgasmic hypersensitivity of the clitoral glans paralleling the hypersensitivity of the glans of the penis that men experience as an aspect of MRP.

Methods

Participants

The participants were 174 women aged 19-52 years (mean age 25 years) enrolled in a variety of academic programs. The women were informed of the sexual nature of the study and advised that only those 19 years of age and older would be asked to participate.

Procedure

The study protocol was approved by the university research ethics committee of the host institution. Recruitment of participants was done during class time but the questionnaire was completed outside of class. Students were assured that participation was voluntary, confidential, and anonymous, and that they would not be compensated in any way. Those who filled out the questionnaire were also given the opportunity to participate in a one-on-one online interview designed to better our understanding of the phenomenon at hand. Of the women who completed the questionnaire, 11 agreed to further participate in the one-on-one online interview.

Research questionnaire

The questionnaire consisted of 16 questions with various response options, administered in bubble sheet format, and designed to cover a range of sexual behaviours and experiences considered pertinent for an exploratory study on post-orgasmic experiences in women. The key question asked to identify women who did and did not experience post-orgasmic clitoral hypersensitivity was: "When you have an orgasm, does your clitoris become sensitive? (A. Yes, at the time of orgasm; B. Yes, but not until after orgasm; C. No)". The other related question was: "After you have an orgasm, do you wish to continue direct clitoral stimulation? (A, Yes, right away; B. Yes, but I focus on him; C. Yes, but I need some time; D. No)".

The other 14 questions provided background sexual behaviour information. The seven questions considered pertinent to the current study and reported on here dealt with: experience of sexual intercourse; current frequency of intercourse; current frequency of masturbation; frequency of orgasm due to each of these two behaviours; frequency of multiple orgasms; frequency of multiple orgasms during intercourse.

Interview questionnaire used for follow-up with a sub-sample of participants

All participants were invited to complete a contact information attached sheet if they were interested in participating in a subsequent one-on-one online interview via instant messaging. The women were informed that the online interviews were of a sexual nature and that if they were uncomfortable speaking about their own sexuality, they should not participate. Moreover, the women were encouraged to create new e-mail addresses which would maintain their complete anonymity if they were concerned about revealing their identity. We expected that this form of interviewing would provide a greater sense of security and lessen any potential embarrassment given the personal nature of the questions being asked. The students who showed interest in participating (i.e., those who submitted their e-mail addresses) were contacted via e-mail.

The interview style was semi-structured, in that there were a set of questions each participant was asked (see Table 1) but there was also room for the students to question, clarify, or elaborate whenever they chose.

The 11 interview participants were also invited to add anything that they thought might be relevant to our understanding of their experience. The online interview took from 10-20 min; 8 women took less than 15 min. The interviewer engaged in the online interview from a computer station in the Psychology Computer Lab, all responses were saved in a password-protected file. None of the questions were left blank; if a woman did not know the answer or did not want to respond to the question she said so in every instance. The themes were constructed by a single researcher using a grounded theory approach.

Results

Post-orgasmic clitoral hypersensitivity

The sexual behaviour background questionnaire findings were analyzed using SPSS. Since the primary focus of study was to compare women who experienced post-orgasmic clitoral sensitivity to those who did not, we focus first on the question: "When you have an orgasm, does your clitoris become sensitive?" The vast majority of women, 96%, responded to the option "Yes, but not until after the orgasm." Not surprisingly, a chi-square test demonstrated that this option was selected significantly more often than the other two options, [chi square] (2, N = 174) = 114.69, p = .000. The other options were "Yes, at time of orgasm" (0%) and "No" (4.0%). Given the relatively few women (i.e., 7) who reported hOt experiencing post-orgasmic clitoral sensitivity, we were unable to perform any meaningful comparisons between groups on out other measures.

The responses to a related question that asked "After you have an orgasm do you wish to continue direct clitoral stimulation?" were "Yes, right away" (0.6%), "Yes, but I focus on him" (1.7%), "Yes but I need some time" (11.5%), and "No" (86.2%). Overall, 97.7% either did not want post-orgasmic clitoral stimulation or wanted to delay it. This findings suggests that the post-orgasmic clitoral hypersensitivity documented above was aversive.

Background sexual behaviour findings

The selected behaviours highlighted here are reported as percentage of participants answering each of the questions in a particular way. Missing responses were included in the % calculations and ranged from 0%-5.2% for the 7 questions addressed here (mean=3.0% ; 5 of 174 participants). With this proviso, percentages cited below include all participants.

Current sexual behaviour frequency and related orgasm frequency

Overall, 90.2% of participants had ever had sexual intercourse. In the total sample, 61.5% had intercourse daily, 3 times a week, or weekly (i.e., weekly or more often) and 30.5% of the total sample "had orgasms due to intercourse" weekly or more often. In the total sample, masturbation frequency was weekly or more often for 45.4% with 41.4% of the total sample reporting orgasm due to masturbation at that frequency. Overall, the frequency and source of orgasms among participants suggests that their reports of post-orgasmic clitoral hypersensitivity were informed by wide experience.

Multiple orgasms

When participant were asked "How often do you have multiple orgasms?", responses were every time (6.9%), only with masturbation (10.3%), only with intercourse (8.6%), occasionally (25.3%), rarely, (21.8%), and never (27.0%). With specific reference to intercourse experience, responses to the question "How many orgasms do you usually have during intercourse?" were none (29.9%), one (50.6%), more than one (13.8%).

Follow-up interview findings specifically on post-orgasmic clitoral hypersensitivity

The interviews were designed to uncover common themes that women experienced. Only 11 women participated in the one-on-one online interviews. The interviews were strikingly similar. The majority of interview participants described a hypersensitivity, or extreme sensitivity of the clitoris (90.9%) and indicated that this occurred "shortly after orgasm" (90.9%). As well, 90.9% experienced this sensation in the whole clitoris and 63.6% went on to state that the tip of the clitoris was especially sensitive. Almost 73% of interview subjects reported that they did not like direct clitoral contact during the period of hypersensitivity. When asked if they noticed any differences between intercourse and masturbation pertaining to this sensitivity, 36.4% of the interviewees declined or did not have an answer to this questions, whereas 63.6% of those who did answer indicated that they experienced this sensation more acutely with intercourse than masturbation. These women suggested that this may have been due to the fact that their partner did not know when to stop (i.e., when the hypersensitivity begins). While 27.3% of interviewees said the hypersensitivity lasted a few seconds to a minute, 45.4% said it lasted 5-10 min. Almost 73% indicated that they did not like direct clitoral stimulation at this point. Over half of the women (54.5%) told their partners about the hypersensitivity so as to avoid direct clitoral contact after orgasm. Among those who told their partners, half did so by saying their clitoris was very sensitive and that they did not want direct stimulation while the others actually compared their clitoris to a penis and likened their experience to the post-orgasmic sensitivity of their partner's penis.

The following sampling of quotations, taken directly from interviews, are representative of the themes identified: "If I have an orgasm touch very lightly"; "It is not comfortable to apply direct pressure anymore"; "He knows that if he wants to give me another clitoral orgasm right away, he has to stop stimulating right away after orgasm"; "Its like men too I guess, after they have orgasmed the penis is sensitive too and requires a period of time to recover"; "My orgasms are pretty short, but just as it happens any pressure on the clitoris hurts"; "Yes the whole clitoris, but possibly the tip is the most sensitive"; "Well ... almost painful if the tip is touched"; "Maybe how sensitive my clitoris is after orgasm has a little bit to do with how much pressure is applied during stimulation"; "During masturbation, I can kind of control the pressure at my own discretion"; "I personally don't like direct stimulation at this point"; "not direct genital stimulation ... but kissing and rubbing the rest of my body yes"; "Its important to communicate about it"; "10-20 seconds"; "around 5-10 minutes"; "I put up with it until he orgasms and then sex is done."

Discussion

This exploratory study was prompted by the lack of research on the post-orgasmic experiences of women and by the apparent assumption in the literature that women either do not have a post-orgasmic refractory period characterized by genital hypersensivity and reduced arousability as in men or are they are less affected by it. The fact that 96% of the participants in our sample of orgasmically-experienced, mostly young adult women reported post-orgasmic clitoral hypersensivity (and particularly sensitivity of the clitoral glans) invites reconsideration of a refractory period in women. The previously reviewed literature on the homologous developmental origins of the clitoris and penis and the post-orgasmic rise in blood levels of prolactin in both sexes gives anatomical and neurobiological reasons to expect parallels between the refractory period in men and the post-orgasmic period of clitoral hypersensitivity reported by women in the present study.

Out study provides some support for this parallel, or for a refractory period characteristic for women, but some limitations should be noted as a basis for considering future research. Our sample consisted of relatively young university student volunteers who had been fully informed about the sexual nature of study. While the background data on their sexual behaviour suggested sufficient experience of orgasm to give us confidence in their reports of post-orgasmic clitoral hypersensitivity, further studies on a larger general population sample are needed to provide data on different age groups. Studies that allow comparisons based on sexual orientation are also needed.

Due to the small number of participants who did not experience post-orgasmic clitoral hypersensitivity, we could not assess possible differences between women who did and did not have this experience. The measure of post-orgasmic clitoral hypersensity we used also merits attention. For the purposes of this exploratory study, we employed a global measure of hypersensitivity but future research should refine the measure to focus on clitoral sensitivity at various points during sexual arousal as well as post-orgasmically. In this respect, it is of interest that none or out 174 participants reported clitoral hypersensitivity during orgasm. More precise data on the nature of the aversive state of post-orgasmic hypersensitivity, including measures of duration and intensity, will also help to differentiate this post-orgasmic experience from the sensitivity some women report to direct clitoral stimulation during sexual encounters (e.g., Masters & Johnson, 1966).

Since we anticipate other similarities in male and female refractory periods beyond clitoral/penile post-orgasmic hypersensitivity, further studies of post-orgasmic proctolin release and function in women will be informative. If, as we expect, prolactin release is central to post-orgasmic clitoral hypersensitivity in women, it would of interest to know whether pregnant and breast-feeding women have increased sensitivity given the role of prolactin during these physiological states (Friesen & Huang, 1973). Similarly, individual differences in endogenous levels of prolactin may correlate with clitoral sensitivity. Studies on post-orgasmic levels of proctolin in women who do not experience post-orgasmic clitoral hypersensitivity would also be informative.

The refractory period in men is characterized by detumescence and lack of subsequent arousability in addition to hypersensitivity of the glans. The present study addressed the question of post-orgasmic arousability in women only indirectly by asking participants whether they wished to continue direct clitoral stimulation after they had an orgasm.

In this respect, 86.2% said "no" and 11.5% said "yes, but need more time". One inference is that their immediate arousability would be impeded because of post-orgasmic clitoral hypersensitivity (and perhaps secondarily because of their usual reliance on clitoral stimulation for arousal). Apart from any central effects, this pattern would appear to parallel the refractory period in men.

In men, the detumescence of the penis in the refractory period is associated with greater difficulty in having a subsequent erection. The clitoris undergoes similar detumescence post-orgasmically although many women continue sexual activity after orgasm. However, in the case of intercourse, clitoral engorgement is not necessary for intercourse and it is possible to continue to stimulate a woman's genitalia without applying direct pressure to her clitoris. For men, erection is usually required for intercourse. Further study of post-orgasmic detumescence and arousability in women will provide insight into refractory period similarities and differences between men and women in these respects. For example, in term of vasocongestion women may have a shorter recovery period, possibly due to the size differences of the spongiosum tissue.

The capacity for multiple orgasm in women and the effect of orgasm-induced prolactin release is also of interest. The participants in the present study showed considerable diversity in frequency of this multiple. Studies of prolactin and neurotransmitter levels in the participants who experienced multiple orgasm all the time (6.9%), occasionally (25.3%), and never (27.0%) might well have provide insights into refractory period-related phenomena in women and men.

Overall, the present study questioned the widely accepted premise that only men experience a post-orgasmic refractory period. Our contention was not that this phenomenon is identical in women and men but rather that the study of post-orgasmic clitoral hypersensitivity and related refractory period factors in women has been neglected. We hope the present findings will stimulate further research on this and related aspects of women's sexual response.

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Aliisa K. Hurnphries (1) and Jan Cioe (1)

(1) Psychology Department, University of British Columbia Okanagan, Kelowna, BC

Correspondence concerning this article should be addressed to Jan Cioe, Ph.D., R.Psych., Psychology Department, University of British Columbia Okanagan, Kelowna, B.C., VIV 1V7. E-mail: jan.cioe@ubc.ca
Table 1 Follow-up interview questions

(a) Do you notice any change in sensation in your
    clitoris when you have an orgasm?

(b) How exactly would you describe these
    sensations, in your own words?

(c) When exactly does this change occur?

(d) Where exactly does this change occur?

(e) Do you like to continue sexual activity at this
    point?

(f) Is direct clitoral stimulation at this point
    uncomfortable?
(g) How long does this sensation last?

(h) Does it happen every time you have an orgasm?

(i) Do you have multiple orgasms?

(j) Is there a window of time when this sensitivity
    prevents multiple orgasms?

(k) Do you make your sexual partners aware of this
    sensation?
(1) If so, how do you tell them?

(m) What do you wish your partner to know about
    this clitoral hypersensitivity?

(n) Is there any difference between sex with a
    partner and masturbation concerning this
    hypersensitivity?
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