Hypoxia as a potential cause of dyspareunia

Dyspareunia is genital pain before, during or after penile-vaginal sexual intercourse. The prevalence of dyspareunia ranges from 8 to 22%. Sexual intercourse concomitant with a pelvic organic lesion is likely to cause pain in most cases. However, in these cases, the pain depends not only on sexual intercourse. In its basic definition, dyspareunia in women is considered an idiopathic affection without a typical organic constitution. It is only present with penile-vaginal penetration. Long-term hypoxia in perineal muscles can cause muscle and perimuscular changes, leading to chronic pain not sufficiently responding to standard therapy. During the entrance examination to our previous study on dyspareunia, we noted significantly lower pulse oximetry levels in the perineal area of affected women. We aimed to compare pulse oximetry oxygen saturation (SpO2) of dyspareunia-affected women to healthy, pain-free women. A retrospective study was performed. The study participants were women who had participated in our previously published study on dyspareunia. This retrospective study was approved by the Ethical Committee. The study included 62 women: 31 dyspareunia-affected women in the treatment group and 31 healthy women in the control group.

During their examinations, women in the dyspareunia and control groups were measured for SpO2. The procedure was performed in the vulvo-perineal rear region, involving the commissure and the bulbospongiosus muscle. Median and mean SpO2 were compared between the treatment and control groups. Testing for sample size accuracy was performed retroactively.

There were 31 participants in each group. The SpO2 data were skewed and did not follow a Gaussian distribution. The Mann-Whitney U test was run to determine differences in perineum oximetry between the treatment group and controls. The median SpO2 was 91 in the treatment group and 92 in the control group. This difference was statistically significant, p = 0.002. Sample size accuracy was assured by post hoc calculation.

Idiopathic dyspareunia is inherent in cohabitation muscle pain that standard therapy could not explain nor treat. We detected clinically meaningfully decreased levels of SpO2 in affected patients. We compared pelvic oximetry between dyspareunia-affected women in the treatment and control groups. This comparison showed significant hypoxia in the perineal muscle area (p = 0.002). Our results may help us understand the source of this pain and guide treatment accordingly.