Stress urinary incontinence is a condition where urine leaks out when a person coughs, sneezes, laughs, lifts up, walks or engages in physical exertion. One of the most common complaints in relation to the pelvic floor during pregnancy, and which can have a negative impact on personal hygiene, everyday life, sleep, emotional state, social life and quality of life. Although urinary leakage is a common symptom of pregnancy, many women do not

seek medical attention for it as they feel it is a normal part of pregnancy or embarrassed discussing it with their physicians (1-3).

The pelvic floor undergoes significant anatomic, hormonal, mechanical and functional changes during pregnancy. As the uterus grows, it puts more downward pressure on the bladder, the urethra, the pelvic fascia and the levator ani muscles. Hormonal changes can lead to loosening of connective tissues and less stiffness of the tissues that hold the urethra and bladder neck up. This causes the bladder outlet to lower too far and the tube (urethra) to twist during coughing or straining. In addition, enlargement of the levator hiatus, loss of perineal support and weak pelvic floor muscles can exacerbate urethral closure and urethral leakage (4-6).

The activity of the pelvic floor muscles plays a key role in maintaining urinary and faecal continence in situations of rapid rise in intra-abdominal pressure. These muscles, when contracted properly, help to support the bladder neck, squeeze the urethra and prevent any urine leakage. This protective response may be compromised by decreased muscle strength or decreased endurance. Factors such as maternal age, gestational age, BMI, multiparity, previous vaginal delivery, constipation, chronic cough and limited PFM exercises may also play a role in the risk. But sometimes, stress urinary incontinence is not solely due to a weak pelvic floor (7-9).

Posture, gait, spine, abdomen and pelvis are also affected during pregnancy. As the maternal body centre moves forward the anterior pelvic tilt and lumbar lordosis increases. This adaptation can affect the mechanics of the abdominal wall, diaphragm, hip muscles, pelvic floor, and lumbar stabilizers. The abdominal wall may become less effective due to diastasis recti and hip abductors and external rotators may be weak, which can affect pelvic stability. Therefore, pelvic girdle pain, dysfunction of the sacroiliac joint, low back pain and generalized joint hypermobility can exist with urinary symptoms and affect the severity (10, 11).

Stress urinary incontinence is generally assessed by obstetric history, pelvic floor muscle strength or quality of life based on the previous studies. There are fewer studies that have investigated the anatomy of the pelvic floor and the orthopedic factors simultaneously, especially in women who are pregnant. An integrated evaluation may give a more comprehensive answer as to why the urinary leakage is mild in some women, and moderate or severe in others. Also the recognition of modifiable musculoskeletal factors could help to develop targeted antenatal rehabilitation strategies (8, 12, 13).

The present study was therefore conducted to determine the association between pelvic floor muscle anatomy, orthopedic characteristics, and the severity of stress urinary incontinence among pregnant women attending Bannu Medical College, Bannu. The study specifically examined bladder neck descent, levator hiatus dimensions, urethral mobility, pelvic floor muscle strength and endurance, pelvic tilt, lumbar lordosis, diastasis recti, hip muscle strength, and related musculoskeletal conditions. It was expected that the findings would assist clinicians in recognizing women at increased risk and support the integration of pelvic floor and lumbopelvic assessment into antenatal care.

This analytical cross-sectional study was conducted at Bannu Medical College, Bannu, from February 2025 to July 2025. The study aimed to determine the association between pelvic floor muscle anatomy, orthopedic factors, and the severity of stress urinary incontinence among pregnant women. A total of 77 pregnant women attending the obstetrics and antenatal clinics during the study period were enrolled. Participants were recruited through non-probability consecutive sampling until the required sample size was achieved. Ethical approval was obtained from the institutional ethical review committee before starting the study, and written informed consent was secured from every participant after explaining the study objectives, assessment procedures, potential benefits, and confidentiality measures. Eligible for inclusion were women of reproductive age (18-40 years), with a singleton pregnancy, and a minimum gestational age of 20 weeks. Women who reported leakage of urine when they cough, sneeze, laugh, lift, walk, or do any action that brings up pressure in the abdomen were evaluated for stress urinary incontinence. Patients excluded were women who had a history of urinary tract infection, any previous neurological condition, congenital pelvic abnormalities, a previous pelvic reconstructive surgery, urinary urgency without stress, or any medical condition that made physical examination difficult. Women who were unable to understand the assessment procedure or did not provide consent were also excluded. Data about the mother's age, the gestational age, her BMI, gravidity, parity, previous mode of delivery, instrumental delivery, constipation, chronic cough, pelvic girdle pain, low back pain, and previous pelvic floor exercises were collected on a structured data collection sheet. ICIQ-UI SF was used to determine the presence and severity of stress urinary incontinence. The questionnaire assessed the frequency of leakage, estimated amount of urine loss and impact of symptoms on daily activities. Stress urinary incontinence was classified as mild, moderate or severe based on the total score and clinical findings. On the other hand, participants were also asked what activities they typically find to be triggers and how often they leak per day/week and whether they use protective pads. Standardized clinical and ultrasound-based methods were used to evaluate the pelvic floor anatomy and muscle function. Transperineal sonography was conducted in the semi-reclined postures on a full bladder. The levator hiatus area at rest and during the Valsalva was measured, bladder neck position, bladder neck descent, urethral rotation angle and perineal body length were measured. The strength of the pelvic floor muscle was assessed by digital examination (modified Oxford grading) which ranged from 0 (no muscle contraction) to 5 (strong muscle contraction). Muscle endurance was assessed as the duration of time (in seconds) in which a voluntary contraction of the pelvic floor muscles could be sustained. All assessments were conducted using the same protocol and a trained examiner to minimise variation in measurements and were preceded by consistent instructions to the participant prior to each measurement. The orthopedic and musculoskeletal evaluation included anterior pelvic tilt, lumbar lordosis, diastasis recti width, hip abductor strength, hip external rotator strength, sacroiliac joint dysfunction, generalized joint hypermobility, low back pain and pelvic girdle pain. The pelvis and lumbar spine were evaluated by measuring pelvic tilt and lumbar lordosis with a standard inclinometer and diastasis recti was measured on a controlled abdominal contraction at the level of the umbilicus. The strength of hip muscles was assessed by handheld dynamometer and joint hypermobility was assessed by the Beighton score system. All information were processed and analysed with IBM SPSS Statistics. Data for continuous variables were presented as mean ± standard deviation and for categorical variables were presented as frequencies and percentages. Continuous variables were compared among the three incontinence groups by one-way analysis of variance, and categorical variables were compared among the three groups by the chi-square test. Pearson or Spearman correlation was used depending on the distribution of the data. Using binary logistic regression, independent predictors of moderate to severe stress urinary incontinence were determined after adjustment for age, body mass index, gestational age, parity and previous vaginal delivery. The p-value of < 0.05 was regarded as statistically significant.

Overall, 77 pregnant women were studied. The mean age was 28.7 ± 4.6 years for their mean gestation age of 30.8 ± 5.1 weeks. The mean body mass index was 28.4 ± 3.7 kg/m². The majority of the participants had multiple pregnancies and almost half had had at least one previous vaginal delivery. Of the women who were stressed urinary incontinence 35 had mild, 27 had moderate and 15 had severe.

Table 1. Demographic and obstetric characteristics of the participants

Of those participating, 35 had mild (45.5%), 27 had moderate (35.1%) and 15 had severe (19.5%) urinary incontinence. The most frequently mentioned symptoms were leakage during coughing, sneezing, laughing and lifting heavy objects. About a third of the women said they used protective pads due to urine leakage.

Table 2. Clinical characteristics and severity of stress urinary incontinence

There were significant differences in the pelvic floor anatomical measurements among grades of stress urinary incontinence. The levator hiatus area measured during Valsalva manoeuvre was larger in women with severe incontinence when compared to those with mild symptoms, as was also bladder neck descent and urethral rotation angle. As urinary incontinence worsened, there was a progressive decrease in pelvic floor muscle strength and endurance.

Table 3. Pelvic floor muscle characteristics according to incontinence severity

Relationships were also observed between orthopedic and musculoskeletal issues and the severity of stress urinary incontinence. Anterior pelvic tilt and lumbar lordosis and diastasis recti were more apparent and hip abductor weakness was more pronounced in women with severe symptoms. Other findings included that the severe incontinence group had a higher prevalence of pelvic girdle pain and generalized joint hypermobility.

Table 4. Orthopedic factors according to severity of stress urinary incontinence

Stress urinary incontinence severity had a significant positive correlation with bladder neck descent, levator hiatus area during Valsalva and urethral rotation angle on correlation analysis. There were moderate positive correlations with anterior pelvic tilt, lumbar lordosis and diastasis recti width. Pelvic floor muscle strength, pelvic floor endurance and hip abductor strength, however, were negatively associated with symptom severity.

Table 5. Correlation of anatomical and orthopedic factors with stress urinary incontinence severity

A binary logistic regression analysis of the associations among the factors was conducted to determine those factors associated with moderate-to-severe stress urinary incontinence independently. Bladder neck descent was also significantly greater after adjustment for age, body mass index, gestational age, parity and previous vaginal delivery, as was the area of the levator hiatus during Valsalva.The strength of the pelvic floor muscles and the degree of anterior pelvic tilt were also significant after controlling for age, BMI, gestational age, parity and previous vaginal delivery. Increased body mass index and multiparity was also independently associated with increased severity.

Table 6. Predictors of moderate-to-severe stress urinary incontinence

Overall, the findings demonstrated that greater pelvic floor anatomical changes and unfavorable orthopedic alignment were associated with more severe stress urinary incontinence. Bladder neck descent, enlargement of the levator hiatus, reduced pelvic floor muscle strength and increased anterior pelvic tilt appeared to be the most important factors influencing symptom severity among pregnant women.

Figure 1. Distribution of stress urinary incontinence severity among pregnant women (n = 77).

Mild stress urinary incontinence was observed in 35 (45.5%) women, moderate in 27 (35.1%), and severe in 15 (19.5%).

The present study demonstrated that the severity of stress urinary incontinence among pregnant women was closely associated with both pelvic floor muscle characteristics and orthopedic factors. Women with severe symptoms showed greater bladder neck descent, larger levator hiatus dimensions, wider urethral rotation angles, and reduced pelvic floor muscle strength and endurance. These findings indicate that pregnancy-related changes in pelvic support structures may reduce urethral stability during increases in intra-abdominal pressure. As pregnancy advances, hormonal influences, uterine enlargement, maternal weight gain, and increasing pressure on the pelvic floor may collectively weaken the continence mechanism. The higher proportion of women with mild and moderate symptoms also suggests that stress urinary incontinence often develops gradually and may become more noticeable as pelvic floor support deteriorates (14, 15). The strongest anatomical factors to be correlated with severity of symptoms were bladder neck descent and enlargement of the levator hiatus. Increased movement of the bladder neck with straining may be due to decreased support from the pelvic fascia and pelvic floor muscles. In like manner, an enlarged levator hiatus during Valsalva's manoeuvre can also be indicative of hyperdistensibility or hypofunction of the levator ani complex. Such anatomical changes may cause a decrease in the pressure the urethra can withstand and result in leakage of urine when coughing, sneezing, laughing, lifting, or exercising. The urethral rotation angle was greater for women with severe stress urinary incontinence, which further indicates the role of urethral mobility in the development of symptoms. A shorter perineal body length and an asymmetric levator muscle shape may also be a factor in having poor pelvic support and incontinence (16, 17). The strength and endurance of the pelvic floor muscles decreased as SUI was increased from mild to severe. This finding further underscores the importance of having a functioning pelvic floor during pregnancy. Powerful contraction of the pelvic floor muscles helps to support the bladder neck and urethra, and can resist rapid rises in abdominal pressure. During coughing and/or stressful activities, women who have weak muscles may not be able to keep the urethra closed as well. There can also be a lack of muscle endurance which can make it difficult to keep the bladder closed for extended periods of time when standing, walking or doing repetitive tasks. The results are in favour of the importance of early assessment of pelvic floor muscle function during antenatal assessment, especially with women who had previously had vaginal delivery, multiparity, high BMI, constipation, or chronic cough (18, 19). Other orthopedic and musculoskeletal factors were also significantly associated with the severity of urinary incontinence due to stress. Those with severe symptoms exhibited higher anterior pelvic tilt, increased lumbar lordosis, wider diastasis recti, and a lower hip abductor and external rotator strength. The altered lumbopelvic alignment can alter the direction of forces that are applied to the pelvic floor, and can alter coordination between the abdominal wall, diaphragm, spinal stabilizers and pelvic floor muscles. This may cause further stresses to the pelvis, and diastasis recti may alter the ability to control abdominal pressure. Hip stabilising muscle weakness can also further de-stabilise the pelvis and limit functional support for standing and movement. Severe women have a higher prevalence of pelvic girdle pain and sacroiliac joint dysfunction and generalized joint hypermobility, suggesting that SUI may be part of a larger pattern of lumbopelvic instability (20). Bladder neck descent, enlarged levator hiatus, diminished strength of the pelvic floor muscles, anterior pelvic tilt, diastasis recti, higher body mass index and multiparity were all independently associated with moderate to severe SUI in the regression analysis. These findings indicate that urinary symptoms should not be the sole criteria for assessment and that anatomical, muscular and orthopedic factors should also be taken into account. Antenatal screening programs could be enhanced by being supplemented with pelvic floor muscle testing, and a basic musculoskeletal examination, using questionnaires about incontinence. The results should be interpreted with some consideration of limitations, however. The cross-sectional design does not allow the determination of the cause-effect relationship and the relatively small sample was selected from a single institution. In addition, some clinical measures may be affected by the technique used by the examiner. Future longitudinal studies with larger multicentre samples should examine if the correction of pelvic alignment, strengthening of hip and abdominal muscle strength and structured pelvic floor muscle training can decrease progression of symptoms throughout pregnancy and following childbirth.

Stress urinary incontinence in pregnant women was significantly associated with pelvic floor anatomical changes and unfavorable orthopedic characteristics. Greater bladder neck descent, enlargement of the levator hiatus, increased urethral mobility, reduced pelvic floor muscle strength, excessive anterior pelvic tilt, increased lumbar lordosis, diastasis recti, and weak hip muscles were linked with more severe symptoms. These findings emphasize the need for comprehensive antenatal assessment that includes both pelvic floor and musculoskeletal evaluation. Early identification of high-risk women and the introduction of targeted pelvic floor and lumbopelvic rehabilitation may help reduce the severity of urinary leakage and improve maternal quality of life.