The Role of Proprioceptive Deficits, Psychosocial Factors and Inflammation in Pregnancy-related Pelvic Girdle Pain

The presence of PPGP in the last month will be questioned. PPGP will be defined as: "self-reported pain in the lumbar area, between the twelfth rib and the gluteal fold, with or without pain between the posterior iliac crest and the gluteal fold, particularly in the vicinity of the sacroiliac joints that may radiate in the posterior thigh and could occur separately or in conjunction with pain in the symphysis pubis"

The presence of PPGP in the last two weeks will be questioned. PPGP will be defined as: "self-reported pain in the lumbar area, between the twelfth rib and the gluteal fold, with or without pain between the posterior iliac crest and the gluteal fold, particularly in the vicinity of the sacroiliac joints that may radiate in the posterior thigh and could occur separately or in conjunction with pain in the symphysis pubis"

The presence of PPGP in the last two weeks will be questioned. PPGP will be defined as: "self-reported pain in the lumbar area, between the twelfth rib and the gluteal fold, with or without pain between the posterior iliac crest and the gluteal fold, particularly in the vicinity of the sacroiliac joints that may radiate in the posterior thigh and could occur separately or in conjunction with pain in the symphysis pubis"

Upright standing balance control will be measured as center-of-pressure displacements with a force plate.

Upright standing balance control will be measured as center-of-pressure displacements with a force plate.

Upright standing balance control will be measured as center-of-pressure displacements with a force plate.

The MDQ quantifies the extent of functional limitation in daily life due to low back pain: 10 items, total score range 0 - 100. Higher scores indicate higher levels of disability.

The MDQ quantifies the extent of functional limitation in daily life due to low back pain: 10 items, total score range 0 - 100. Higher scores indicate higher levels of disability.

The QBPDS assesses disability in individuals with low back pain and PPGP: 20 items, total score range 0 - 100. Higher scores indicate higher levels of disability.

Pain intensity will be rated on the NPRS that ranges from 0 ("no pain") to 10 ("the worst pain imaginable").

Individuals with PPGP will indicate the pain locations on a body chart.

Current body weight will be measured (kg)

Current body weight will be measured (kg)

Current body composition will be measured with bioelectrical impedance analysis.

Center-of-pressure displacements in response to ankle muscle and lower back muscle vibration (60 Hz, 15s) during upright standing will be measured with a force plate.

Center-of-pressure displacements in response to ankle muscle and lower back muscle vibration (60 Hz, 15s) during upright standing will be measured with a force plate.

During the laterality recognition task, participants view 40 pictures of a model that has its lower back bent or rotated to the left or the right side. They will be asked to judge the direction of movement as quickly and accurately as possible. Average speed (in seconds) of response time and average accuracy of the answers (in %) will be recorded.

During the laterality recognition task, participants view 40 pictures of a model that has its lower back bent or rotated to the left or the right side. They will be asked to judge the direction of movement as quickly and accurately as possible. Average speed (in seconds) of response time and average accuracy of the answers (in %) will be recorded.

The FreBAQ assesses back-specific body perception: 9 items, total score range 0 - 45. Higher score indicate a more disturbed body perception.

The FreBAQ assesses back-specific body perception: 9 items, total score range 0 - 45. Higher score indicate a more disturbed body perception.

The TSK evaluates fear of movement and pain-related fear: 17 items, total score range 17 - 68. Higher scores indicate higher levels of pain-related fear of movement.

The TSK evaluates fear of movement and pain-related fear: 17 items, total score range 17 - 68. Higher scores indicate higher levels of pain-related fear of movement.

During the PhoDA-SEV, participants view 40 pictures of daily life activities. They will be asked to imagine themselves performing the depicted activity and to indicate to which extent they believe that the activity is harmful to their back on a scale from 0 ("not harmful at all") to 100 ("extremely harmful"): 40 items, total score range 0 - 100. Higher scores indicate a higher perceived harmfulness of physical activities.

During the PhoDA-SEV, participants view 40 pictures of daily life activities. They will be asked to imagine themselves performing the depicted activity and to indicate to which extent they believe that the activity is harmful to their back on a scale from 0 ("not harmful at all") to 100 ("extremely harmful"): 40 items, total score range 0 - 100. Higher scores indicate a higher perceived harmfulness of physical activities.

The FABQ consists of 16 statements for which the participant rates her agreement with the statement on a scale from 0 ("completely disagree") to 6 ("completely agree"): 16 items, total score range 0 - 96). Higher scores indicate that poorer fear avoidance beliefs are held.

The FABQ consists of 16 statements for which the participant rates her agreement with the statement on a scale from 0 ("completely disagree") to 6 ("completely agree"): 16 items, total score range 0 - 96). Higher scores indicate that poorer fear avoidance beliefs are held.

The PCS contains 13 statements on thoughts and emotions possibly related to the experience of pain, for which the participants rates her agreement: 13 items, total score range 0 - 52. Higher scores indicate higher levels of pain catastrophizing.

The PCS contains 13 statements on thoughts and emotions possibly related to the experience of pain, for which the participants rates her agreement: 13 items, total score range 0 - 52. Higher scores indicate higher levels of pain catastrophizing.

The EDS evaluates perinatal depression: 10 items, total score range 0 - 30. Higher scores indicate higher levels of pregnancy-related depression.

The PRAQ-R2 evaluates pregnancy-related anxiety: 10 items, total score range 10 - 50. Higher scores indicate higher levels of pregnancy-related anxiety.

The TPDS assesses pregnancy-related distress: 16 items, total score range 0 - 48). Higher scores indicate higher levels of pregnancy-related stress.

The DASS-21 evaluates depressive mood, anxiety and stress in general: 21 items, total score per subscale (Depression, Stress, Anxiety) range 0 - 21. Higher scores indicate higher levels of depressive mood (DASS-21-Depression), anxiety (DASS-21-Anxiety) and stress (DASS-21-Stress).

The DASS-21 evaluates depressive mood, anxiety and stress in general: 21 items, total score per subscale (Depression, Stress, Anxiety) range 0 - 21. Higher scores indicate higher levels of depressive mood (DASS-21-Depression), anxiety (DASS-21-Anxiety) and stress (DASS-21-Stress).

The LAPS comprehensively evaluates negative and positive affect, hedonic tone and independent variables (including cognitive and overall functioning, meaningful life and happiness): 16 items. It contains three subscores, which are calculated by adding the score on items 1-4 (Negative Affect), items 5-8 (Positive Affect) and items 9-12 (Hedonic Tone). Negative Affect subscale: 4 items, score range 0 - 40, higher scores indicate higher levels of negative affect. Positive Affect subscale: 4 items, score range 0 - 40, higher scores indicate higher levels of positive affect. Hedonic Tone subscale: 3 items, total score range 0 - 30, higher scores indicate higher levels of hedonic tone.

The LAPS comprehensively evaluates negative and positive affect, hedonic tone and independent variables (including cognitive and overall functioning, meaningful life and happiness): 16 items. It contains three subscores, which are calculated by adding the score on items 1-4 (Negative Affect), items 5-8 (Positive Affect) and items 9-12 (Hedonic Tone). Negative Affect subscale: 4 items, score range 0 - 40, higher scores indicate higher levels of negative affect. Positive Affect subscale: 4 items, score range 0 - 40, higher scores indicate higher levels of positive affect. Hedonic Tone subscale: 3 items, total score range 0 - 30, higher scores indicate higher levels of hedonic tone.

The GAD-7 evaluates generalized anxiety: 7 items, total score range 0 - 21.

The GAD-7 evaluates generalized anxiety: 7 items, total score range 0 - 21.

The MAAS evaluates the emotional bond between mother and child antenatally, while the MPAS assesses this bond postnatally: 19 items, total score range 0 - 95

The PCI evaluates whether one uses passive or active coping strategies: 34 items, total score range 0 - 100

The PCI evaluates whether one uses passive or active coping strategies: 34 items, total score range 0 - 100

The LOT-R contains 10 items: 3 evaluating optimism, 3 evaluating pessimism and 4 filler items, total score range on each subscale (optimism, pessimism) 0 - 12.

The LOT-R contains 10 items: 3 evaluating optimism, 3 evaluating pessimism and 4 filler items, total score range on each subscale (optimism, pessimism) 0 - 12.

The SOC-13 contains 13 items, total score ranges 0 - 91

The SOC-13 contains 13 items, total score ranges 0 - 91

Pain frequency will be assessed with the question: 'How often do you experience pain?' Response options will include: Some days (1), Most days (2), and Every day (3).

The SF-36 evaluates health-related quality of life, 8 scales: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health. Scores for the different scales are converted and pooled using a scoring key, for a total score ranging 0 - 100

The SF-36 evaluates health-related quality of life, 8 scales: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health. Scores for the different scales are converted and pooled using a scoring key, for a total score ranging 0 - 100

Serum concentrations of inflammatory mediators will be measured in a blood sample.

The following pain provocation tests for PPGP will be performed: thigh thrust and trendelenburg test. A score of 1 will be assigned to each test that provokes the participants' pain, a score of 0 will be assigned to each test that does not provoke the pain. All scores will be combined into one overall score.

The participant will perform the ASLR test in supine lying: she will be asked to lift one leg 20 cm off the bed, and a score between 0 and 5 will be assigned depending on the difficulty experienced (0= "not difficult at all, 1= minimally difficult, 2= somewhat difficult, 3 = fairly difficult, 4= very difficult, 5= unable to do).

The age of the participant will be noted (in years)

The age of the participant will be noted (in years)

Annual household income will be questioned (in Euro)

Annual household income will be questioned (in Euro)

Marital status be questioned (single, married/registered partnership)

Marital status be questioned (single, married/registered partnership)

The highest degree obtained will be recorded.

The highest degree obtained will be recorded.

The current profession will be recorded, as well as the type of work (sedentary work, manual work, heavy work)

The current profession will be recorded, as well as the type of work (sedentary work, manual work, heavy work)

The number of previous pregnancies will be recorded.

The number of previous child deliveries will be recorded.

The number of stillbirths and live births will be recorded.

The number of previous miscarriages will be recorded.

Job status will be recorded (i.e., working full-time, working part-time, in sick leave)

In case of sick leave, we will ask whether this is pregnancy-related or not, and the total number of sick leave days will be noted.

Job status will be recorded (i.e., working full-time, working part-time, in sick leave)

In case of sick leave, we will ask whether this is pregnancy-related or not, and the total number of sick leave days will be noted.

Smoking habits will be questioned by using the following categories: every day smoker (smokes now and smokes every day), someday smoker (smokes now, but not every day), former smoker (has quit smoking), never smoker

Smoking habits will be questioned by using the following categories: every day smoker (smokes now and smokes every day), someday smoker (smokes now, but not every day), former smoker (has quit smoking), never smoker

Alcohol use will be questioned by using the following categories: every day drinker (drinks now and drinks every day), someday drinker (drinks now, but not everyday), former drinker (has quit drinking now), never drinker.

Alcohol use will be questioned by using the following categories: every day drinker (drinks now and drinks every day), someday drinker (drinks now, but not everyday), former drinker (has quit drinking now), never drinker.

Habitual physical activity will be questioned using the following categories: no physical activity, physical activity, but less than recommended (<150min moderate intensity/week), physical activity, as recommended.

Habitual physical activity will be questioned using the following categories: no physical activity, physical activity but less than recommended (<150min moderate intensity/week), physical activity as recommended.

The PSQI assesses sleep quality over the past month: 19 items, global sleep quality scores range 0 - 21

The PSQI assesses sleep quality over the past month: 19 items, global sleep quality scores range 0 - 21

Height will be measured and reported in cm.

Height will be measured and reported in cm.

Pre-pregnancy body weight will be questioned and reported in kg.

The number of falls experienced during previous pregnancies will be noted. The following question will be asked: "During your previous pregnancies, did you experience any loss of balance, resulting in a fall where some part of your body--other than your feet--touched the ground?"

If the participant experienced a fall during a previous pregnancy, the gestational week during which the fall(s) occurred will be noted.

If the participant experienced a fall during a previous pregnancy, the situation during which the falls occurred will be noted, by using the following categories: trip, slip, during stair ascent, during stair descent, during athletic activity.

If the participant experienced a fall during a previous pregnancy, the injury severity associated with the falls will be noted by using the following categories: no injury, mild injury requiring home treatment, major injury requiring medical attention

The presence of urinary incontinence during previous pregnancies (yes/no), and the recovery of urinary incontinence postpartum (full, partial, no recovery) will be questioned.

The presence of incontinence for stool and gas during previous pregnancies (yes/no), and the recovery of incontinence for stool and gas postpartum (full, partial, no recovery) will be questioned.

We will ask whether the previous children date of delivery

We will ask whether the previous deliveries were vaginal deliveries of caesarean sections.

Information on presence of episiotomy (yes/no) and occurrence of vaginal tear (yes/no) in previous deliveries will be collected.

We will ask whether an instrument was used during the delivery: forceps, vacuum cup,...

We will ask whether the women are pregnant through assisted reproductive treatment

The number of falls experienced during the current pregnancy or postpartum period will be noted. The following question will be asked: "Did you experience any loss of balance, resulting in a fall where some part of your body--other than your feet--touched the ground?"

If the participant experienced a fall during or after the current pregnancy, the timepoint during which this fall occurred wil be noted.

If the participant experienced a fall during or after the current pregnancy, the situation during which the falls occurred will be noted, by using the following categories: trip, slip, during stair ascent, during stair descent, during athletic activity.

If the participant experienced a fall during or after the current pregnancy, the injury severity associated with the falls will be noted by using the following categories: no injury, mild injury requiring home treatment, major injury requiring medical attention

Urinary incontinence will be evaluated with the Pelvic Floor Distress Inventory (PFDI-20). The PFDI-20 contains 20 items, total score range 0 - 300

We will ask whether the women are pregnant through assisted reproductive treatment

We will ask whether the women experience morning sickness during their current pregnancy.

We will ask the date of delivery.

Information on presence of episiotomy (yes/no) and occurrence of vaginal tear (yes/no) will be collected

We will ask whether an instrument was used during the delivery: forceps, vacuum cup,...

Fear of falling during postural control measurements will be rated after each measurement on the NRS that ranges from 0 ("no fear") to 10 ("the worst fear imaginable").

Fear of falling during postural control measurements will be rated after each measurement on the NRS that ranges from 0 ("no fear") to 10 ("the worst fear imaginable").