Clinical Guidelines

MENU

GUIDELINE UPDATES - This guideline was last updated 01/07/2022

Anxiety and distress

It is well documented that the finding of an abnormality on cervical screening has the potential to cause anxiety and distress.[1][2][3][4][5][6][7][8][9][10] The degree and duration of psychological distress experienced by women with abnormal cervical screening depends on their understanding of the meaning of the results.[4][10] As women are usually asymptomatic when a cervical abnormality is detected on routine screening, they may feel particularly vulnerable and distressed. Younger women and those who have never had children are at increased risk of high levels of anxiety.[3]

Women’s concerns may be centred around several themes:

  • perceived threat to life, frequently with an assumption that there will be inevitable progression to invasive cancer
  • worry about future fertility
  • concern about risk of transmission to an intimate partner
  • concerns about disclosing human papillomavirus (HPV) status to an intimate partner
  • guilt, shame and self-blame associated with past sexual behaviour
  • anger and mistrust of intimate partners; suspicion about infidelity.

As the trend in cervical screening shifts towards HPV testing, there is an emerging literature on the specific psychosocial and psychosexual issues associated with the psychological impact of positive HPV results and women’s understanding of the implications of this result.

Confirmation of a positive HPV result may carry with it an additional burden of psychological distress due to the direct association with exposure to a sexually transmitted infection.[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Anxiety, fears and confusion surrounding the uncertainty of the meaning of cervical pathology are compounded by issues of stigma and poor understanding about exposure to HPV. Psychosocial and psychosexual consequences may be significant and persistent, with the potential to result in clinical depression or an anxiety disorder requiring psychological interventions and treatment.

With increasing knowledge and understanding across the community that exposure to HPV infection is a pre-requisite for the development of cervical cancer, the general public understands the causal link between sexual behaviour and cancer more clearly than the implication of a cytological prediction of an intraepithelial lesion after a screening test.

Women who have not received vaccination, even though it was available to them, may feel distressed that they have failed to adequately protect themselves from infection. Those who have received the full course of HPV immunisation may feel distressed that the vaccine has 'failed'.

Anger about exposure to HPV may lead to suspicion about the fidelity of the intimate partner and have a negative effect on intimate relationships. Additionally, women may have fears about transmitting the virus to current or future sexual partners. Psychosexual function may be impaired with decreased libido and lower frequency of intercourse.[25]

Management of distress

Information needs to be delivered in a sensitive manner and should be tailored to individual patient characteristics: age, education level, health literacy, parity, cultural/religious beliefs, mental health concerns and language proficiency.

  • Information should be delivered compassionately, non-judgmentally and in plain language (not medical jargon).
  • Provision of printed information resources should supplement verbal communication. If possible, pamphlets, fact sheets or booklets should be available in community language translations for culturally and linguistically diverse populations.

Information provided to women could:

  • explain the natural history of HPV infection
  • normalise the incidence of HPV infection as a commonly acquired community infection
  • reinforce that HPV infections are usually transient and do not progress to invasive cancer
  • reinforce the benefits of having identified the infection through screening, enabling monitoring and intervention as appropriate to prevent cancer by treating pre-cursor lesions
  • convey the message that, although HPV infection is relatively common, cervical cancer is uncommon in screened populations
  • address concerns about transmitting the virus to intimate partners and discuss safe sex practices
  • provide reassurance to reduce the stigma associated with HPV infection, then directing the conversation towards addressing the necessary next steps in evaluation and investigation
  • explain the colposcopic procedure and possible outcomes.

Healthcare providers should be mindful that the emotional distress associated with receiving information about a positive HPV result may temporarily impair a woman’s capacity to process and understand the result. Prior to the end of the consultation, health-care providers should reiterate the information and the next steps to be taken, checking that the woman has clearly understood the information.

Providing adequate information in a supportive environment, offering opportunities to ask questions and seek clarification, and ensuring a plan for communicating the next steps or investigations will usually be sufficient to allay the distress of most women. For those who demonstrate persistent elevated anxiety and distress, referral to other services for counselling may be helpful. Available services vary according to location, but may include women’s health services, GPs (who can initiate a mental health care plan), or counselling services within the local health facility.

Effective counselling strategies may be beneficial in alleviating distress for most women.[26][27][28][29][30]

Counselling techniques and interventions with evidence of effectiveness may include:[31]

  • psycho-education
  • brief emotional support
  • supportive-expressive therapy
  • cognitive behavioural therapy (CBT)
  • problem-solving approaches
  • relaxation, meditation or mindfulness skills.

Ideally, counselling should be offered as a face-to-face (where possible) discussion, rather than by phone or letter. Formal referral to a suitably qualified counsellor (such as a clinical psychologist, social worker, sexual health counsellor or women’s health counsellor) should be considered for women who experience persistent emotional distress. Australian guidelines for screening, assessment and management of anxiety and depression in adult cancer patients provide a useful resource.[31]

Back to top

Women with special needs

Some women with pre-existing psychosocial comorbidities may require referral to specialist services for expert assessment and intervention. Such women may be under-screened and therefore at higher risk of HPV infection.[32][33] Factors to consider as special circumstances include:

  • a history of trauma (including torture) – women may experience 'triggering' of trauma responses when informed about a positive HPV test. They should be offered immediate mental health assessment and counselling.[32][34]
  • known prior sexual abuse (childhood or adult)[35][36]
  • current or past history of intimate partner violence[37][38]
  • disabilities (physical and intellectual)[39]
  • history of substance misuse
  • significant mental health history
  • a history of female genital mutilation and/or surgical revision procedures.

Women from culturally and linguistically diverse backgrounds need to be given information in their first language, via health care interpreters or printed information resources. This is especially important for women from countries where there is no population-based cervical screening.

Women without stable accommodation and those who are socially marginalised may be non-compliant with necessary investigations following a positive oncogenic HPV test result. They may be difficult to locate or lost to follow up, frequently only re-emerging when symptomatic.[40]

For some women the first disclosure of sexual abuse may occur at the time of first speculum examination or in the context of receiving a positive HPV test result. Clinicians need to be aware of, and consider referral to, specialist state-based sexual assault counselling services for women with an identified background of sexual abuse.

For all women with additional psychosocial risk factors health professionals have a duty of care to be aware of the range of specialist treatment services within their jurisdictions, and to refer appropriately following consultation and consent from the woman.

Back to top

Education and information

It is important to educate women about the need for cervical screening and to differentiate HPV testing from other sexually transmitted infection testing. For vulnerable women who may not be well connected to mainstream health services, attendance for cervical screening affords health professionals an additional opportunity to provide education about screening for other sexually transmitted infections and safe sex practices such as condom use, pregnancy counselling and emergency contraception.[41][42][43][44][45][4][46][47][48][49][50][51][52][53][10]

Association of cervical screening with HPV testing may deter some women from participating in screening programs.[10] Attitudes and behaviours may include:

  • perceptions by women that they are not at risk of HPV infection due to their personal behaviours.
  • deeming HPV screening as unnecessary if they have received HPV vaccination.[54]
  • avoidance due to fear of a positive result and what that may mean for intimate relationships.

Women with psychosocial risk factors may be difficult to engage in screening programs.[55][56][57] For those who do undertake screening, elevated psychological distress following a positive HPV result may impede their ability to continue with recommended investigations and to adhere to cervical screening guideline recommendations.[58]

Education is required to counter the potential for distress that may be experienced by some women as the changes to cervical screening policy are implemented. The change to primary HPV testing, the later recommended age to commence screening and the longer screening interval may be perceived by some women as a cost-driven reduction in surveillance, thus exposing them to an increased risk of developing invasive cancer.

Effective education and information may assist women in decision-making, at the same time assisting their psychological adjustment, treatment compliance and satisfaction with care.

Back to top

Psychosocial resources

Although the overwhelming majority of women who have a positive HPV test will not go on to develop cervical cancer, psychosocial guidelines that have been developed for addressing issues of anxiety and psychological distress in the context of cancer are useful for all health professionals.

The most comprehensive evidence-based guideline on psychosocial care is the 2003 Clinical practice guidelines for the psychosocial care of adults with cancer published by the National Breast Cancer Centre (now Cancer Australia).

This resource has been supplemented by:

Psychosocial Care Referral Checklist (2008)

Clinical Guidance for Responding to Suffering in Adults with Cancer (2014)

All of these resources can be accessed from Cancer Australia

For information and resources about sexual health see Health Direct Australia or refer to specialist sexual health services in your local jurisdiction.

Back to top

Author(s):

References

  1. Sharp L, Cotton S, Cruickshank M, Gray NM, Harrild K, Smart L, et al. The unintended consequences of cervical screening: distress in women undergoing cytologic surveillance. J Low Genit Tract Dis 2014 Apr;18(2):142-50 Available from: http://www.ncbi.nlm.nih.gov/pubmed/24270192.
  2. Vesco KK, Whitlock EP, Eder M, Lin J, Burda BU, Senger CA, et al. 2011 May Available from: http://www.ncbi.nlm.nih.gov/pubmed/22132428.
  3. Gray NM, Sharp L, Cotton SC, Masson LF, Little J, Walker LG, et al. Psychological effects of a low-grade abnormal cervical smear test result: anxiety and associated factors. Br J Cancer 2006 May 8;94(9):1253-62 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16622462.
  4. Juraskova I, Butow P, Sharpe L, Campion M. 'What does it mean?' Uncertainty, trust and communication following treatment for pre-cancerous cervical abnormalities. Psychooncology 2007 Jun;16(6):525-33 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16988948.
  5. Lagro-Janssen T, Schijf C. What do women think about abnormal smear test results? A qualitative interview study. J Psychosom Obstet Gynaecol 2005 Jun;26(2):141-5 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16050540.
  6. Laubmeier KK; Zakowski SG. The role of objective versus perceived life threat in the psychological adjustment to cancer. Psychol Health 2004;19:425-437.
  7. Rogstad KE. The psychological impact of abnormal cytology and colposcopy. BJOG 2002 Apr;109(4):364-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12013155.
  8. Baileff A. Cervical screening: patients' negative attitudes and experiences. Nurs Stand 2000 Jul;14(44):35-7 Available from: http://www.ncbi.nlm.nih.gov/pubmed/11975277.
  9. Bennetts A, Irwig L, Oldenburg B, Simpson JM, Mock P, Boyes A, et al. PEAPS-Q: a questionnaire to measure the psychosocial effects of having an abnormal pap smear. Psychosocial Effects of Abnormal Pap Smears Questionnaire. J Clin Epidemiol 1995 Oct;48(10):1235-43 Available from: http://www.ncbi.nlm.nih.gov/pubmed/7561985.
  10. Kavanagh AM, Broom DH. Women's understanding of abnormal cervical smear test results: a qualitative interview study. BMJ 1997 May 10;314(7091):1388-91 Available from: http://www.ncbi.nlm.nih.gov/pubmed/9161314.
  11. McCaffery KJ, Irwig L, Turner R, Chan SF, Macaskill P, Lewicka M, et al. Psychosocial outcomes of three triage methods for the management of borderline abnormal cervical smears: an open randomised trial. BMJ 2010 Feb 23;340:b4491 Available from: http://www.ncbi.nlm.nih.gov/pubmed/20179125.
  12. Graziottin A, Serafini A. HPV infection in women: psychosexual impact of genital warts and intraepithelial lesions. J Sex Med 2009 Mar;6(3):633-45 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19170869.
  13. Marlow LA, Waller J, Wardle J. The impact of human papillomavirus information on perceived risk of cervical cancer. Cancer Epidemiol Biomarkers Prev 2009 Feb;18(2):373-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19190156.
  14. Pirotta M, Ung L, Stein A, Conway EL, Mast TC, Fairley CK, et al. The psychosocial burden of human papillomavirus related disease and screening interventions. Sex Transm Infect 2009 Dec;85(7):508-13 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19703844.
  15. Kitchener HC, Fletcher I, Roberts C, Wheeler P, Almonte M, Maguire P. The psychosocial impact of human papillomavirus testing in primary cervical screening-a study within a randomized trial. Int J Gynecol Cancer 2008 Jul;18(4):743-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17944916.
  16. Brown L, Ritvo P, Howlett R, Cotterchio M, Matthew A, Rosen B, et al. Attitudes toward HPV testing: interview findings from a random sample of women in Ontario, Canada. Health Care Women Int 2007 Oct;28(9):782-98 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17907007.
  17. Kahn JA, Slap GB, Bernstein DI, Tissot AM, Kollar LM, Hillard PA, et al. Personal meaning of human papillomavirus and Pap test results in adolescent and young adult women. Health Psychol 2007 Mar;26(2):192-200 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17385971.
  18. Maggino T, Casadei D, Panontin E, Fadda E, Zampieri MC, Donà MA, et al. Impact of an HPV diagnosis on the quality of life in young women. Gynecol Oncol 2007 Oct;107(1 Suppl 1):S175-9 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17825395.
  19. Waller J, McCaffery K, Kitchener H, Nazroo J, Wardle J. Women's experiences of repeated HPV testing in the context of cervical cancer screening: a qualitative study. Psychooncology 2007 Mar;16(3):196-204 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16858719.
  20. McCaffery K, Waller J, Nazroo J, Wardle J. Social and psychological impact of HPV testing in cervical screening: a qualitative study. Sex Transm Infect 2006 Apr;82(2):169-74 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16581749.
  21. Perrin KK, Daley EM, Naoom SF, Packing-Ebuen JL, Rayko HL, McFarlane M, et al. Women's reactions to HPV diagnosis: insights from in-depth interviews. Women Health 2006;43(2):93-110 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17000613.
  22. Maissi E, Marteau TM, Hankins M, Moss S, Legood R, Gray A. The psychological impact of human papillomavirus testing in women with borderline or mildly dyskaryotic cervical smear test results: 6-month follow-up. Br J Cancer 2005 Mar 28;92(6):990-4 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15785734.
  23. McCaffery K, Waller J, Forrest S, Cadman L, Szarewski A, Wardle J. Testing positive for human papillomavirus in routine cervical screening: examination of psychosocial impact. BJOG 2004 Dec;111(12):1437-43 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15663132.
  24. Conaglen HM, Hughes R, Conaglen JV, Morgan J. A prospective study of the psychological impact on patients of first diagnosis of human papillomavirus. Int J STD AIDS 2001 Oct;12(10):651-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/11564332.
  25. Campion MJ, Brown JR, McCance DJ, Atia W, Edwards R, Cuzick J, et al. Psychosexual trauma of an abnormal cervical smear. Br J Obstet Gynaecol 1988 Feb;95(2):175-81 Available from: http://www.ncbi.nlm.nih.gov/pubmed/2831933.
  26. Diaz ML. Counseling the patient with HPV disease. Obstet Gynecol Clin North Am 2013 Jun;40(2):391-402 Available from: http://www.ncbi.nlm.nih.gov/pubmed/23732038.
  27. Galaal K, Bryant A, Deane KH, Al-Khaduri M, Lopes AD. Interventions for reducing anxiety in women undergoing colposcopy. Cochrane Database Syst Rev 2011 Dec 7;(12):CD006013 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22161395.
  28. Irwin K, Montaño D, Kasprzyk D, Carlin L, Freeman C, Barnes R, et al. Cervical cancer screening, abnormal cytology management, and counseling practices in the United States. Obstet Gynecol 2006 Aug;108(2):397-409 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16880312.
  29. Bastani R, Yabroff KR, Myers RE, Glenn B. Interventions to improve follow-up of abnormal findings in cancer screening. Cancer 2004 Sep 1;101(5 Suppl):1188-200 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15316914.
  30. Karasz A, McKee MD, Roybal K. Women's experiences of abnormal cervical cytology: illness representations, care processes, and outcomes. Ann Fam Med 2003 Nov;1(4):196-202 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15055408.
  31. Butow P, Price MA, Shaw JM, Turner J, Clayton JM, Grimison P, et al. Clinical pathway for the screening, assessment and management of anxiety and depression in adult cancer patients: Australian guidelines. Psychooncology 2015 Sep;24(9):987-1001 Available from: http://www.ncbi.nlm.nih.gov/pubmed/26268799.
  32. Ackerson K. A history of interpersonal trauma and the gynecological exam. Qual Health Res 2012 May;22(5):679-88 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22068042.
  33. Olesen SC, Butterworth P, Jacomb P, Tait RJ. Personal factors influence use of cervical cancer screening services: epidemiological survey and linked administrative data address the limitations of previous research. BMC Health Serv Res 2012 Feb 14;12:34 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22333392.
  34. Farley M, Golding JM, Minkoff JR. Is a history of trauma associated with a reduced likelihood of cervical cancer screening? J Fam Pract 2002 Oct;51(10):827-31 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12401150.
  35. Weitlauf JC, Frayne SM, Finney JW, Moos RH, Jones S, Hu K, et al. Sexual violence, posttraumatic stress disorder, and the pelvic examination: how do beliefs about the safety, necessity, and utility of the examination influence patient experiences? J Womens Health (Larchmt) 2010 Jul;19(7):1271-80 Available from: http://www.ncbi.nlm.nih.gov/pubmed/20509787.
  36. Cadman L, Waller J, Ashdown-Barr L, Szarewski A. Barriers to cervical screening in women who have experienced sexual abuse: an exploratory study. J Fam Plann Reprod Health Care 2012 Oct;38(4):214-20 Available from: http://www.ncbi.nlm.nih.gov/pubmed/23027982.
  37. Gandhi S, Rovi S, Vega M, Johnson MS, Ferrante J, Chen PH. Intimate partner violence and cancer screening among urban minority women. J Am Board Fam Med 2010 May;23(3):343-53 Available from: http://www.ncbi.nlm.nih.gov/pubmed/20453180.
  38. Loxton D, Powers J, Schofield M, Hussain R, Hosking S. Inadequate cervical cancer screening among mid-aged Australian women who have experienced partner violence. Prev Med 2009 Feb;48(2):184-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19026675.
  39. Iezzoni LI, McCarthy EP, Davis RB, Harris-David L, O'Day B. Use of screening and preventive services among women with disabilities. Am J Med Qual 2001 Jul;16(4):135-44 Available from: http://www.ncbi.nlm.nih.gov/pubmed/11477958.
  40. Ackerson K, Gretebeck K. Factors influencing cancer screening practices of underserved women. J Am Acad Nurse Pract 2007 Nov;19(11):591-601 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17970859.
  41. Monsonego J, Cortes J, da Silva DP, Jorge AF, Klein P. Psychological impact, support and information needs for women with an abnormal Pap smear: comparative results of a questionnaire in three European countries. BMC Womens Health 2011 May 25;11:18 Available from: http://www.ncbi.nlm.nih.gov/pubmed/21612599.
  42. Ackerson K, Preston SD. A decision theory perspective on why women do or do not decide to have cancer screening: systematic review. J Adv Nurs 2009 Jun;65(6):1130-40 Available from: http://www.ncbi.nlm.nih.gov/pubmed/19374678.
  43. Bertram CC, Magnussen L. Informational needs and the experiences of women with abnormal Papanicolaou smears. J Am Acad Nurse Pract 2008 Sep;20(9):455-62 Available from: http://www.ncbi.nlm.nih.gov/pubmed/18786022.
  44. Goldsmith MR, Austoker J, Marsh G, Kehoe ST, Bankhead CR. Cervical screening result communication: a focus-group investigation of English women's experiences and needs. Qual Saf Health Care 2008 Oct;17(5):334-8 Available from: http://www.ncbi.nlm.nih.gov/pubmed/18842971.
  45. Garland SM; Quinn MA. How to manage and communicate with patients about HPV? Int J Gynecol Obstet 2006;94(Suppl 1):S106-112.
  46. Gray NM, Sharp L, Cotton SC, Avis M, Philips Z, Russell I, et al. Developing a questionnaire to measure the psychosocial impact of an abnormal cervical smear result and its subsequent management: the TOMBOLA (Trial of Management of Borderline and Other Low-grade Abnormal Smears) trial. Qual Life Res 2005 Aug;14(6):1553-62 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16110935.
  47. McCaffery K, Irwig L. Australian women's needs and preferences for information about human papillomavirus in cervical screening. J Med Screen 2005;12(3):134-41 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16156944.
  48. Waller J, McCaffery K, Nazroo J, Wardle J. Making sense of information about HPV in cervical screening: a qualitative study. Br J Cancer 2005 Jan 31;92(2):265-70 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15655553.
  49. Anhang R, Goodman A, Goldie SJ. HPV communication: review of existing research and recommendations for patient education. CA Cancer J Clin 2004 Sep;54(5):248-59 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15371283.
  50. Anhang R, Wright TC Jr, Smock L, Goldie SJ. Women's desired information about human papillomavirus. Cancer 2004 Jan 15;100(2):315-20 Available from: http://www.ncbi.nlm.nih.gov/pubmed/14716766.
  51. Onyeka BA, Martin-Hirsch P. Information leaflets, verbal information and women's knowledge of abnormal cervical smears and colposcopy. J Obstet Gynaecol 2003 Mar;23(2):174-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12745564.
  52. Philips Z, Johnson S, Avis M, Whynes DK. Communicating mild and borderline abnormal cervical smear results: how and what are women told? Cytopathology 2002 Dec;13(6):355-63 Available from: http://www.ncbi.nlm.nih.gov/pubmed/12485171.
  53. Khanna N, Phillips MD. Adherence to care plan in women with abnormal Papanicolaou smears: a review of barriers and interventions. J Am Board Fam Pract 2001 Mar;14(2):123-30 Available from: http://www.ncbi.nlm.nih.gov/pubmed/11314919.
  54. Mather T, McCaffery K, Juraskova I. Does HPV vaccination affect women's attitudes to cervical cancer screening and safe sexual behaviour? Vaccine 2012 May 2;30(21):3196-201 Available from: http://www.ncbi.nlm.nih.gov/pubmed/22425789.
  55. Burger EA, Nygård M, Gyrd-Hansen D, Moger TA, Kristiansen IS. Does the primary screening test influence women's anxiety and intention to screen for cervical cancer? A randomized survey of Norwegian women. BMC Public Health 2014 Apr 15;14:360 Available from: http://www.ncbi.nlm.nih.gov/pubmed/24735469.
  56. Walsh JC. The impact of knowledge, perceived barriers and perceptions of risk on attendance for a routine cervical smear. Eur J Contracept Reprod Health Care 2006 Dec;11(4):291-6 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17484195.
  57. Behbakht K, Lynch A, Teal S, Degeest K, Massad S. Social and cultural barriers to Papanicolaou test screening in an urban population. Obstet Gynecol 2004 Dec;104(6):1355-61 Available from: http://www.ncbi.nlm.nih.gov/pubmed/15572502.
  58. Philips Z, Avis M, Whynes DK. Introducing HPV triage into the English cervical cancer screening program: consequences for participation. Women Health 2006;43(2):17-34 Available from: http://www.ncbi.nlm.nih.gov/pubmed/17000609.

Back to top

WEBSITE UPDATES - This website was last updated 01/07/2022