The genitourinary syndrome of menopause (GSM) is caused by the decrease in estrogen and other sex steroids, which lead to changes in estrogen-sensitive tissues, i.e. the labias, clitoris, introitus, vagina, urethra and bladder. One of these changes is the reduction of blood flow in the tissues, causing a reduction of vaginal discharge and vaginal lubrication.   

It is well known that aging and chronic hormonal depletion cause changes in the skeletal arteries in postmenopausal women, such as a reduction of their size and elasticity, which leads to a reduction in the blood flow. In this population, a muscle training program was shown to improve the blood flow in specifically trained skeletal muscles [1,2]. Since the arteries irrigating the pelvic floor muscles (PFM) also supply the vulvo-vaginal tissues, PFM training could improve vulvo-vaginal blood flow. The positive effect of a PFM training program on GSM symptoms was observed in a previous case study [3]. However, the impact of such a program on the vulvo-vaginal blood flow has not been investigated to date.  

The internal pudendal artery (IPA) is one of the main vessels irrigating both the vulvo-vaginal tissues and the PFM. Assessment of its blood flow with color Doppler ultrasound has been described before, proximally at the level of the ischial spine and, more distally, at the level of its terminal branch, the dorsal clitoral artery. Moreover, repeatability of these measurements has been demonstrated previously by our research team in young women and in women with GSM. Assessing IPA blood flow and the clitoral blood flow before and after a PFM training program could yield information about the impact of this intervention on vulvo-vaginal blood flow. 

The purpose of this study, therefore, was to assess the impact of a PFM training program on the IPA and the dorsal clitoral artery blood flow in postmenopausal women with GSM.

This prospective interventional cohort study included postmenopausal women aged 55 or over with GSM. The diagnosis of GSM was confirmed by a collaborating gynecologist. Exclusion criteria were pathology, previous treatment or medication likely to interfere with blood flow measurements such as dermatological diseases of the vulva, previous radiotherapy for gynecological cancer and antiestrogenic medication. The dosage of hormonal therapy or arterial hypertension medication had to be stable for at least six months before participation in this study to ensure perineal blood flow stability. Each woman participated in two pre-intervention evaluations (PRE1 and PRE2), a 12-week PFM training program and a post-intervention evaluation (POST). PRE2 was conducted two weeks after PRE1 to document stability of blood flow measurements among the participants. All blood flow evaluations were performed by the same observer. Caffeine and tobacco intake, sexual activity, physical activity as well as use of creams or other product applications in the vulvar and gluteal areas were controlled for a period of 24 hours before the assessment as these have been shown to influence IPA and dorsal clitoral artery blood flow parameters. 

For the IPA blood flow measurements, participants were asked to rest in the prone position for 15 minutes to ensure standardized conditions. Using a clinical ultrasound system (Voluson E8, GE healthcare), three measurements of the IPA blood flow were taken with a 2-7 MHz curved-array probe at the level of the ischial spine on the participant’s right gluteal area. Participants then had to rest for an additional 15 minutes in the supine position for assessment of the clitoral blood flow. With a 4-13 MHz linear probe on the clitoris, measurements were taken again three times. Each time, the peak systolic velocity, time-averaged maximum velocity and pulsatility index were collected. The clearest waveform in a pulsed-wave Doppler recording was selected for analysis. 

The 12-week training program included a weekly one-hour PFM training intervention with an experienced physiotherapist and daily home-based progressive PFM exercises.

Paired-samples t-tests were used to assess 1) blood flow stability between PRE1 and PRE2 and 2) blood flow differences between pre-intervention measurements (mean of PRE1 and PRE2) and post-intervention measurements (POST).

Thirty-one women with a mean age of 68.0 ± 6.6 and mean parity of 1.8 ± 1.1 were recruited. Among the participants, 20 were sexually active (with intercourse), 12 were taking local hormonal therapy and two were taking systemic hormonal therapy. No change of dosage or use of HT during the study was reported. Three participants dropped out of the study for personal reasons (time constraint). 

Pre-intervention measurements stability:
There was no significant difference between PRE1 and PRE2 for all parameter measurements for both arteries (IPA and dorsal clitoral artery) (p> 0.05). 

Impact of intervention on blood flow measurements:
For the IPA blood flow, the peak systolic velocity parameter increased (p=0.031) after the 12-week PFM training program. There was no significant difference for the time-averaged maximum velocity and pulsatility index parameters.

For the dorsal clitoral artery blood flow, the peak systolic velocity parameter also increased (p=0.040) after the 12-week PFM training program. There was no statistically significant change in the time-averaged maximum velocity and pulsatility index parameters.

To our knowledge, this is the first study to assess the impact of a PFM training program on the IPA and the dorsal clitoral artery blood flow. In women with GSM, an improvement in the peak systolic velocity of the blood flow in both arteries was found after the PFM training intervention. Those encouraging results suggest an improvement in IPA vascularization, up to its terminal branches (the clitoral artery), potentially affecting the capillary density in the tissues irrigated by the IPA, which include the PFM, the vagina, the labias and the clitoris. 

Similar to our study findings, other studies in postmenopausal women have shown blood flow improvement after a muscle training program. These improvements were found locally, in the velocity parameter of the femoral artery blood flow [1] and more distally, in the capillary density of the quadriceps [2].

Our research findings are original as they suggest that a PFM training program improves IPA blood flow and clitoral blood flow in women with GSM. Further studies are needed to confirm these results in an RCT.

Nyberg, M., Egelund, J., Mandrup, C. M., Andersen, C. B., Hansen, K. M. B. E., Hergel, I.-M. F., Valbak-Andersen, N., Frikke-Schmidt, R., Stallknecht, B., Bangsbo, J. and Hellsten, Y. (2017), Leg vascular and skeletal muscle mitochondrial adaptations to aerobic high-intensity exercise training are enhanced in the early postmenopausal phase. J Physiol, 595: 2969–2983. doi:10.1113/JP273871
Gavin, T.P., et al., Aging and the Skeletal Muscle Angiogenic Response to Exercise in Women. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 2015. 70(10): p. 1189-1197.
Mercier, J., et al., Pelvic floor muscles training to reduce symptoms and signs of vulvovaginal atrophy: a case study. Menopause (New York, NY), 2016