This study will be conducted to assess the pelvic floor muscle (PFM) activity in primary dysmenorrhea (PD).

Dysmenorrhea, marked by painful menstrual cramps, often involves increased PFM tension, spasms, and inflammation, affecting females' quality of life and productivity. The traditional focus has been on investigating the abdominal region in women with PD. However, this new perspective considers that the hormonal changes experienced during the menstrual cycle in PD patients may lead to a heightened sensitivity of the PFM, not just the abdominal area. This suggests that the pain associated with PD may have a more widespread impact on the pelvic region rather than being localized to the abdomen. Pelvic floor myofascial trigger points (MTrPs) may also exacerbate menstrual pain through the neural pathway.

There is a critical gap in the literature regarding the nature of the association between dysmenorrhea and PFM activity in this population. Yet, it is unknown whether the pain is a cause or result of increased PFM tone, and the nature of the association between menstrual pain and PFM tone in women with PD is also unknown.

So, this study utilizes transabdominal ultrasound (TAU) to examine PFM activity in PD, aiming to clarify how PFM activity contributes to menstrual pain. Understanding these dynamics could lead to preventive strategies and educational efforts highlighting the role of pelvic floor interventions in managing dysmenorrhea, potentially improving treatment methods and overall women's health management.

Inclusion Criteria:

• They should be virgin, healthy female physiotherapy students with PD.
• They have regular menstruation (3-8 days in duration, with 21-35 days in between).
• Their ages will range from 18 to 25 years old.
• Their body mass index (BMI) will range from 18 to 24.9 kg/m2.
• Their waist-to-hip ratio will be less than 0.8.

Exclusion Criteria:

• Any urological or gynecological disorders in the previous 12 weeks (e.g., endometriosis, fibroids).
• Fibromyalgia.
• Severe psychiatric or psychological disorders.
• Those who had taken analgesics in the 12 hours before the assessment.
• Abdominal or pelvic surgery within the past six months.

Seventy-eight female physiotherapy students with PD will participate in this study. They will be selected randomly from the faculty of physical therapy at Cairo University.