Pelvic floor tenderness and pressure pain sensitivity with endometriosis

Testing for pelvic floor tenderness during routine pelvic exams for women with chronic pelvic pain or endometriosis may help identify women who have heightened overall pain sensitivity, according to a cross-sectional study in the European Journal of Obstetrics & Gynecology and Reproductive Biology.¹

“A substantial proportion of women with chronic pelvic pain and endometriosis do not respond to conventional treatments that are targeted at treating pain in the pelvic cavity or the peripheral nervous system, such as hormonal medications or surgery,” said first author Amy Shafrir, ScD, a research scientist at Boston Children’s Hospital in Massachusetts.

Amy Shafrir, ScD

Some patients who do not respond well to conventional treatments have central pain sensitization, according to Shafrir. “This means that treatments directed at relieving pain in the pelvic cavity will not be effective,” she said.

Shafrir told Contemporary OB/GYN® it is difficult in clinical practice to identify patients with chronic pelvic pain and endometriosis who also have central pain sensitization. “We wanted to have a better understanding of how pelvic floor and abdominal tenderness are possibly related to central pain sensitization through the use of pressure pain thresholds at a body site far from the pelvic area; in this case, the non-dominant thumbnail,” she said.

The study comprised 88 females, median age 31.3 years, with endometriosis and/or chronic pelvic pain, who were mostly recruited by the University of Michigan in Ann Arbor between June 2006 and April 2010.

Overall, 50% of participants reported high pelvic floor tenderness, followed by 58% with high uterine tenderness and 42% with high abdominal tenderness.

Pressure intensities needed to elicit 'faint' and 'mild' pain were significantly lower for participants with high versus low pelvic floor tenderness.

But no association was observed between pressure pain sensitivity and abdominal or uterine tenderness (P > 0.11).

On the other hand, women with endometriosis without pain were significantly less likely to have a high pelvic floor, abdominal, and uterine tenderness compared to those with endometriosis with pain: 22.2% vs. 63.0%, 11.1% vs. 50%, and 25.9% vs. 93.3%, respectively.

Participants with chronic pelvic pain also had higher tenderness rates: 60%, 73.3%, and 93.3%, respectively.

“We found it surprising that only pelvic floor tenderness was associated with pressure pain thresholds at the non-dominant thumbnail and not with abdominal tenderness,” said Shafrir, an instructor in pediatrics at Harvard Medical School. “Because endometriosis disease originates in the pelvic cavity, this finding may be akin to migraine patients who have been shown to have decreased pain thresholds and increased pain to brush and heat in body parts usually involving the head, but which may extend to other regions, suggesting a profound process occurring in the central nervous system.”

Women who have overall heightened pain sensitivity can be directed to more appropriate treatment options that target the central nervous system, such as integrated behavioral therapy, physical therapy, or medications.

Future research is also needed, especially prospective studies, to further investigate if pelvic floor tenderness in terms of number of tender areas and focal versus diffuse tenderness are useful measures to identify patients with chronic pelvic pain or endometriosis who will not experience pain symptom relief using standard treatments, according to Shafrir.

“The hope is that in the future we will be able to identify chronic pelvic pain and endometriosis patients with heightened overall pain sensitivity early in their treatment journey to avoid potentially unnecessary medications and surgical interventions,” she said.

Disclosure:

Shafrir reports no relevant financial disclosures.

Reference:

1. Shafrir AL, Martel E, Missmer SA, et al. Pelvic floor, abdominal and uterine tenderness in relation to pressure pain sensitivity among women with endometriosis and chronic pelvic pain. Eur J Obstet Gynecol Reprod Biol. 2021 Sep;264:247-253. doi:10.1016/j.ejogrb.2021.07.029