Paul Yong

Associate Professor

Relevant Degree Programs

Affiliations to Research Centres, Institutes & Clusters



Endometriosis affects one in ten women, and is a common cause of pelvic pain and infertility. It is a condition where tissue from inside the womb, grows outside the womb, typically elsewhere inside the abdomen. In particular, endometriosis causes pelvic pain with intercourse (deep dyspareunia), which can have a devastating impact on women’s quality-of-life and relationships.

The focus of my research is on how endometriosis causes deep dyspareunia. I am investigating the genetic, cellular, nervous system, and psychological factors that lead to pain with intercourse in endometriosis. The goal is to identify the ideal treatments to reduce pain and improve sexual function in endometriosis.

Great Supervisor Week Mentions

Each year graduate students are encouraged to give kudos to their supervisors through social media and our website as part of #GreatSupervisorWeek. Below are students who mentioned this supervisor since the initiative was started in 2017.


Even before being my supervisor he was an exceptional role model in work ethics and research methods. Most importantly, he was very supportive and enthusiastic about my progress academically and professionally. He made sure that I'm being supported through each step of the way and to regain my self worth and confidence. He is truly a remarkable supervisor.

Najla Alsowayan (2019)


I am grateful for Dr. Yong endless support. Big thanks and much appreciation. He always makes time in his busy schedule for his students.

Fahad Alotaibi (2019)


So grateful to have such a brilliant, supportive, and encouraging mentor/supervisor! Thank you, Dr. Paul Yong for your patience and guidance over the last couple years. I am looking forward to learning more from you during my PhD. #GreatSupervisor #UBC @PelvicPainEndo


I'm so lucky to be supervised by two amazing researchers - Happy Supervisor Appreciation Week to Dr. Susan Cox and Dr. Paul Yong @ubcspph @womensresearch @PelvicPainEndo #GreatSupervisor #UBC


Graduate Student Supervision

Doctoral Student Supervision (Jan 2008 - Nov 2020)
Interleukin 1-beta, plasminogen activator system, and nerve growth factor in endometriosis associated deep dyspareunia (2020)

No abstract available.

Master's Student Supervision (2010 - 2018)
Central sensitization in endometriosis-associated deep dyspareunia (2018)

Endometriosis affects 10% of reproductive-aged women and is the presence of ectopic endometrial glands and stroma. It is associated with different types of pain, such as dysmenorrhea, dyschezia, and deep dyspareunia. Deep dyspareunia affects approximately 50% of women with endometriosis. Previous research has suggested that, in addition to disease-specific factors (e.g., Stage), other factors such as comorbid conditions or central sensitization may also play a role in the etiology of deep dyspareunia. The thesis objective is to provide evidence for the role of these other factors in the etiology of deep dyspareunia in endometriosis. I propose that bladder/pelvic floor tenderness and painful bladder syndrome (PBS) are associated with an increased severity of deep dyspareunia in women with endometriosis, and that these factors may be related to central sensitization. In Aim 1, using data from a prospective registry, I found that bladder/pelvic floor tenderness (assess by physical exam) and PBS (diagnosed using established criteria) were independently associated with severity of deep dyspareunia in women with both Stage I/II endometriosis (AOR=1.94, 95% CI 1.11-3.38, p=0.019; AOR=1.99, 95% CI 1.15-3.44, p=0.013; respectively) and Stage III/IV (AOR=2.51, 95% CI 1.25-5.02, p=0.01; AOR=1.90, 95% CI 1.01-3.57, p=0.048; respectively). In Aim 2, by prospectively recruiting patients and measuring their pain-pressure thresholds (PPT), I determined that PPT at extra-pelvic sites were significantly associated with bladder/pelvic floor tenderness in women with endometriosis (t=2.9, p=0.007; t=2.3, p=0.029; respectively). In contrast, there was no association between PPT and PBS.In conclusion, I found that bladder/pelvic floor tenderness and PBS were associated with greater severity of deep dyspareunia, regardless of endometriosis stage. I also found evidence that bladder/pelvic floor tenderness is associated with lower PPT in women with endometriosis, which may indicate the presence of central sensitization. In contrast, PBS was not associated with changes in PPT, and thus may arise in endometriosis through mechanisms other than central sensitization. My findings point to a role for central sensitization, manifesting as bladder/pelvic floor tenderness, in some women with endometriosis-associated deep dyspareunia. Further research is needed to confirm these findings, and to incorporate measures of central sensitization into the clinical management of endometriosis.

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Plasminogen Activator Inhibitor-1 in Endometriosis (2017)

Endometriosis is a disease that affects almost 10% of reproductive-age women, where 50 % of these women have pelvic pain with sexual intercourse. Deep endometriosis is defined as an endometriotic lesion penetrating to a depth of 5 mm or more, and is characterized by both fibrosis (forming nodules) and invasion (into structures such as the colon). Other groups have found that increased plasminogen activator inhibitor-1 (PAI-1) or (SERPINE1) expression was associated with fibrosis and tumor invasion. In addition, a previous study found that the SERPINE1 4G allele (and thus increased gene expression) was associated with increased pain in women with endometriosis, and other work suggested that SERPINE1 may be implicated in local neurogenesis. The objective of this thesis is to determine whether PAI-1 expression is associated with a) deep infiltrating endometriosis; and b) deep dyspareunia. We propose that increased PAI-1 expression will be associated with deep infiltrating endometriosis, and increased pain in endometriosis via an increase in local nerve fibers. We utilized immunohistochemical analysis using a validated PAI-1 antibody. In the first cohort, we examined PAI-1 expression in deep infiltrating endometriosis and compared to endometrioma, superficial endometriosis, and eutopic endometrium. In the second cohort, we examined PAI-1 expression in cul-de-sac endometriosis from women with or without deep dyspareunia. We found higher expression of PAI-1 in deep infiltrating endometriosis (n = 10) compared to superficial endometriosis (n = 10) (p = 0.031) and eutopic endometrium (n = 10) (p = 0.002). In the second cohort, we found lower expression of PAI-1 in women with more severe deep dyspareunia (r = - 0.352, n =35, p = 0.038). However, there was no association between PAI-1 expression and local nerve bundle density. In conclusion, we observed higher PAI-1 expression in deep infiltrating endometriosis, but lower PAI-1 expression in endometriosis from women with deep dyspareunia. Further research is needed to clarify the complexities of PAI-1 expression in endometriosis.

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